Description:A HARMONIC FREQUENCY-MODULATED CONTINUOUS WAVE (FMCW) RADAR SYSTEM AND A METHOD THEREOF
FIELD OF INVENTION
The present subject matter generally relates to radar systems, and more particularly relates to a harmonic frequency-modulated continuous wave (FMCW) radar system, and a method thereof.
BACKGROUND
A harmonic radar system may use one or more harmonic frequencies to track objects. In traditional harmonic radar systems, a single frequency may be transmitted, and a return signal may be analyzed to determine presence and location of such objects. Each year, many people lose their lives buried in avalanches around the world. The problem has aggravated due to global climate change which has resulted in sudden and frequent triggering of avalanches. A key factor influencing the chance of survival is the burial time. If victims are not rescued within the first 15 – 30 minutes, their chance of survival drops rapidly.
FIG. 1A is a block diagram of a conventional harmonic radar system 100, in accordance with prior art. The harmonic radar system 100 includes a transmitter 102, a receiver 104, and a transponder 106 (also known as a tag 106). The transmitter 102 is configured to generate and transmit radio wave signals or microwave signals towards a target. The transmitter 102 comprises an antenna 102-1, a transmission matching network 102-2, a power amplifier 102-3, an oscillator and amplitude modulator 102-4, and an audio signal 102-5. The receiver 104 is configured to process reflected waves received from a transponder 106 in response to the transmitted radio wave signals. The receiver 104 comprises an oscillator 104-1, a mixer 104-2, an amplifier 104-3, a receiver matching network 104-4, an antenna 104-5, an audio amplifier 104-6, and a loudspeaker 104-7. The transponder 106 receives and responds to an incoming signal (such as the transmitted radio wave signals) by emitting the reflected signal in response to a specific interrogation or a stimulus. The transponder 106 comprises a receiving antenna 106-1, a matching network 106-2, a non-linearity, typically implemented as a Schottky diode 106-3, a matching network 106-4, and a transmitting antenna 106-5.
The radar transmitter 102 generates a frequency f0, which is impinged upon the transponder 106 worn by the victim (also referred herein as target) (for example, buried under snow, or any other surface). The tag 106 uses a non-linearity, typically generated by a Schottky diode 106-3, to generate a second (or higher) harmonic frequency N*f0, with typically N=2 corresponding to a second harmonic. The said frequency N*f0 is transmitted back to the receiver 104 which is tuned to N*f0. All other objects in the vicinity, also known as clutter, which reflect the radar signal at f0, are excluded, if the radar receiver 104 is tuned to the harmonic frequency N*f0 generated by the tag 106.
As shown in FIG. 1A, a specific harmonic radar 100 with N=2, has the transmitter 102 tuned at frequency f0, while the corresponding receiver 104 is tuned to 2*f0. In some implementations, the transmitter 102 output is modulated with an audio tone and during demodulation, the receiver 104 extracts this tone to provide an audio indication. A major drawback of the conventional harmonic radar system 100, which are continuous wave (CW) radars, include their inability to determine a distance to the target, if a victim is buried under tens of feet of surface, such as snow. In addition, since the transceiver consisting of the transmitter 102 and receiver 104 has both the fundamental (f0) and harmonic frequency (N*f0), it is very difficult to implement this method inside a compact semiconductor chip, where the harmonics may interact through coupling. There are other drawbacks which include, the transmitted and received frequencies are widely separated causing significant attenuation through snow as only the transmitted or the received frequency may be optimally chosen while the other may be attenuated more due to propagation or antenna loss. Further, the received signal at N*f0 is still absorbed and scattered by various objects in the avalanche debris field (such as rocks, trees etc.) and in a CW radar, which is unable to extract distance separately, this makes it difficult to estimate a depth of the buried victim under the snow.
Further, the need to determine the depth of a buried victim accurately while removing the impact of clutter in a debris field, has generated recent interest in frequency modulated continuous wave (FMCW) radars. FIG. 1B is a block diagram of a conventional FMCW radar system 150, in accordance with prior art. The FMCW radar system 150 includes essential elements of the radar integrated inside an integrated circuit (semiconductor chip). The continuous wave FMCW radar system 150 comprises a microprocessor 108 including a controller 108-1, a signal processing unit 108-2, and an analog to digital converter 108-3. The microprocessor 108 maybe coupled to a radar on chip 110. The radar on chip 110 may include a temperature-compensated crystal oscillator (TCXO) 112, a synthesizer core 114, a Serial Peripheral Interface (SPI) 116, baseband/IF amplifiers 118-1, 118-2, a power amplifier 120, a power splitter 122, a Receive Local Oscillator (Rx LO) 124, a mixer 126, a low-noise amplifier (LNA) 128, and a set of antennas 130-1, 130-2.The FMCW radar system 150 may require to be specifically enabled to support harmonic radar operation.
Some recent FMCW based harmonic radars as depicted in FIG. 1C continue to mix the fundamental frequency (f0) 138, and a second harmonic (N*f0) 136 and intermodulation frequency products 140 in a way that significantly limits their implementation in a semiconductor chip due to signal coupling.
Hence, there is a need for an improved harmonic frequency-modulated continuous wave (FMCW) radar system, and a method thereof in order to address the aforementioned issues.

SUMMARY
In accordance with an embodiment of the present disclosure, a radar is disclosed. The system may include a control unit configured to generate a first set of control signals for a chirp signal to be transmitted based on a set of radar parameters. Further, the control unit is configured to generate a second set of control signals for controlling a frequency of operation based on a set of signal parameters. Furthermore, the control unit is configured to transmit the generated first set of control signals to a radar-on-chip subsystem and transmit the generated second set of control signals to a front-end subsystem. Further, the radar on chip subsystem is communicatively coupled to the control unit comprises a local oscillator configured to operate at a base frequency of operation required for transmission of the chirp signal based on the first set of control signals. The base frequency of operation ranges between a first frequency and a second frequency based on the first set of control signals.
Moreover, the system may include a front-end subsystem communicatively coupled to the radar on chip subsystem and the control unit. The front-end subsystem comprises a front-end module configured to generate at least one output offset frequency based on the base frequency of operation and the generated second set of control signals. The at least one output offset frequency comprises a third frequency value and a fourth frequency value. The first frequency and the second frequency are shifted to the third frequency value and the fourth frequency value. A frequency divider module is configured to divide the generated at least one output offset frequency. A transmitter subsystem communicatively coupled to the frequency divider module. The transmitter subsystem is configured to transmit the divided output offset frequency as a transmit signal to at least one target via a transmit antenna. A receiver subsystem is configured to receive the at least one input offset frequency as a received signal from the at least one target via a receive antenna. The received at least one input offset frequency comprises the third frequency value and the fourth frequency value. Further, transmit the received at least one input offset frequency to a receiver port of the front-end module as an input signal. The front-end module is configured to generate a first frequency of operation based on the received at least one input offset frequency from the receiver subsystem and the generated second set of control signals. The first frequency of operation ranges between the first frequency and the second frequency, and where the third frequency value and the fourth frequency value are shifted to the first frequency and the second frequency.
In accordance with another embodiment, a method for operating a radar is disclosed. The method includes generating, by a processor, a first set of control signals for a chirp signal to be transmitted based on a set of radar parameters. Further, the method includes generating, by the processor, a second set of control signals for controlling a frequency of operation based on a set of signal parameters. Furthermore, the method includes operating, by the radar on chip subsystem, at a base frequency of operation required for transmission of the chirp signal based on the first set of control signals, wherein the base frequency of operation ranges between a first frequency and a second frequency based on the first set of control signals.
The method further includes generating, by a front-end subsystem, at least one output offset frequency based on the base frequency of operation and the generated second set of control signals, wherein the at least one output offset frequency comprises a third frequency value and a fourth frequency value. The first frequency and the second frequency are shifted to the third frequency value and the fourth frequency value. Furthermore, the method includes dividing, by a frequency divider module coupled to the processor, the generated at least one output offset frequency. The method includes transmitting, by the front-end subsystem, the divided output offset frequency as a transmit signal to at least one target via a transmit antenna. Additionally, the method includes receiving, by the front-end subsystem, the at least one input offset frequency as a received signal from the at least one target via a receive antenna, wherein the received at least one input offset frequency comprises the third frequency value and the fourth frequency value. The method includes generating, by the front-end subsystem, a first frequency of operation based on the received at least one input offset frequency and the generated second set of control signals. The first frequency of operation ranges between the first frequency and the second frequency, and where the third frequency value and the fourth frequency value are shifted to the first frequency and the second frequency.
To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the disclosure and are therefore not to be considered limiting in scope. The disclosure will be described and explained with additional specificity and detail with the appended figures.
BRIEF DESCRIPTION OF DRAWINGS
The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which:
FIG. 1A is a block diagram of a conventional harmonic radar system 100, in accordance with prior art;
FIG. 1B is a block diagram of a conventional Frequency-Modulated Continuous Wave (FMCW) radar system, in accordance with prior art;
FIG. 1C is a block diagram of a conventional FMCW based harmonic radar, in accordance with prior art;
FIG. 2A-2B are block diagrams of an exemplary harmonic FMCW radar system, in accordance with an embodiment of the present disclosure;
FIG. 3A-3B are block diagrams of an exemplary front-end subsystem, such as those shown in FIG. 2A-2B, in accordance with an embodiment of the present disclosure;
FIG. 4 is a block diagram of an exemplary transponder, in accordance with an embodiment of the present disclosure;
FIG. 5 is a block diagram illustrating an exemplary apparatus for a harmonic frequency-modulated continuous wave (FMCW) radar, in accordance with an embodiment of the present disclosure;
FIG. 6 is a flow diagram illustrating an exemplary method for operating a harmonic FMCW radar, in accordance with embodiment of the present disclosure;
FIG. 7 is a flow diagram illustrating an exemplary method for operating a harmonic FMCW radar, in accordance with another embodiment of the present disclosure; and
FIG. 8 is a graphical representation of attenuation characteristics of radar or radio signals through snow quantified by the penetration depth, in accordance with another embodiment of the present disclosure.
Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.

DETAILED DESCRIPTION OF THE DISCLOSURE
For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as would normally occur to those skilled in the art are to be construed as being within the scope of the present disclosure. It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the disclosure and are not intended to be restrictive thereof.
In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
The terms "comprise", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that one or more devices or sub-systems or elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other devices, sub-systems, additional sub-modules. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.
Accordingly, the term “module” or “subsystem” should be understood to encompass a tangible entity, be that an entity that is physically constructed permanently configured (hardwired) or temporarily configured (programmed) to operate in a certain manner and/or to perform certain operations described herein.
Referring now to the drawings, and more particularly to FIG. 2A through FIG. 8, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments, and these embodiments are described in the context of the following exemplary system and/or method.
FIG.s 2A-2B are block diagrams illustrating an exemplary radar system 200, in accordance with an embodiment of the present disclosure. In an exemplary embodiment, the radar system 200 may be one of, for example, but not limited to a harmonic FMCW radar system or a frequency-modulated continuous wave (FMCW) radar system or a continuous wave (CW) radar system. In FIGs. 2A-2B, the harmonic FMCW radar system 200 comprises a control unit 202 including a controller 202-1, a signal processing unit 202-2, and an analog to digital converter 202-3. The control unit 202 may be coupled to a radar on chip subsystem 204 (also referred as radar system 204, herein). In one example embodiment, the radar on chip subsystem 204 may be, for example, the FMCW radar on chip subsystem or a CW radar on chip subsystem. In a preferred embodiment, a harmonic FMCW radar system 200 with a FMCW radar-on-chip subsystem 204 is considered. However, a person skilled in the art may apply the same description in case the CW radar subsystem may be used in addition to or in place of the FMCW radar sub-system. The radar system 204 may include, for example, but not limited to, a synthesizer core 208, a Serial Peripheral Interface (SPI) 210, a baseband/IF amplifier 212-1, 212-2, a power amplifier 214, a power splitter 216, a mixer 218, and a low-noise amplifier (LNA) 220. The synthesizer core 206 may further include, but not limited to, a temperature-compensated crystal oscillator (TCXO) 206, and a local oscillator 206. The radar system 204 is further communicatively coupled to a front-end subsystem 222. In the mixer circuit 218, a part of the frequency-modulated transmitted signal is mixed with the received signal, producing a new signal, which may be used to determine the distance (d) and/or velocity of the moving target 132. The frequency of the new signal is the difference between the frequency of the transmitted and received (reflected) signal.
The front-end subsystem 222 may include front-end module (FEM) 222-1, a frequency divider 224, a Bandpass Filter (BPF) 226, a transmitter subsystem 228, a receiver subsystem 230, transmitter antenna for RF out 232-1, and a receiver antenna for RF in 232-2. The harmonic FMCW radar system 200 may further include target 132 comprising a tag 106. The control unit 202 is configured for generating a first set of control signals for a chirp signal to be transmitted based on a set of radar parameters.
FIG. 2B is a block diagram illustrating an exemplary FMCW radar system 200b, in accordance with an embodiment of the present disclosure. Further, the control unit 202 may be configured to generate a second set of control signals for controlling a frequency of operation based on a set of signal parameters. Furthermore, the control unit 202 transmits the generated first set of control signals to a FMCW radar-on-chip subsystem 204. The control unit 202 may be configured to transmit the generated second set of control signals to a front-end subsystem 222.
The FMCW radar on chip subsystem 204 comprises a local oscillator 206 configured to operate at a base frequency of operation required for transmission of the chirp signal based on the first set of control signals. The base frequency of operation ranges between a first frequency and a second frequency based on the first set of control signals. The front-end subsystem 222 may be communicatively coupled to the FMCW radar on chip subsystem 204 and the control unit 202. The front-end subsystem 222 comprises a front-end module 222-1 configured to generate at least one output offset frequency based on the base frequency of operation and the generated second set of control signals. The at least one output offset frequency comprises a third frequency value and a fourth frequency value. The first frequency and the second frequency are shifted to the third frequency value and the fourth frequency value. The front-end subsystem 222 further comprises the frequency divider module 224 configured to divide the generated at least one output offset frequency. In case the radar on chip subsystem 204 is a CW radar subsystem, then the first frequency of operation may be equal to the base frequency of operation and the fourth frequency of operation may be equal to the third frequency of operation, wherein this system 200 can also support the continuous wave (CW) mode of operation in addition to the FMCW mode of operation.
The transmitter subsystem 228 is communicatively coupled to the frequency divider module 224 and configured to transmit the divided output offset frequency as a transmit signal to at least one target 132 via a transmit antenna 232-1. The receiver subsystem 230 may be configured to receive the at least one input offset frequency as a received signal from the at least one target 132 via a receive antenna 232-2. The received at least one input offset frequency comprises the third frequency value and the fourth frequency value.
Further, the receiver subsystem 230 may be configured to transmit the received at least one input offset frequency to a receiver port of the front-end module 222-1 as an input signal. The front-end module 222-1 may be configured to generate a first frequency of operation based on the received at least one input offset frequency from the receiver subsystem 230 and the generated second set of control signals. The first frequency of operation ranges between the first frequency and the second frequency, and the third frequency value and the fourth frequency value are shifted to the first frequency and the second frequency. In case the radar on chip subsystem 204 is a CW radar subsystem, then the second frequency may be equal to the first frequency and the fourth frequency may be equal to the third frequency, wherein this system can also support the continuous wave (CW) mode of operation in addition to the FMCW mode of operation.
In an exemplary embodiment, during the transmission phase, the base frequency of operation may include f1’ to f2’, where first frequency may be f1’ and a second frequency may be f2’. The output offset frequency may be f1 to f2, where f1 may be third frequency and f2 may be fourth frequency. The divided output offset frequency may be f1/2 to f2/2.
Similarly, during the reception phase, the at least one input offset frequency may be f1 to f2, and the first frequency of operation may include f1’ to f2’, where first frequency may be f1’ and a second frequency may be f2’.
In an exemplary embodiment, in case the radar subsystem 204 corresponds to the CW radar subsystem, the first frequency may be equal to the second frequency and the fourth frequency may be equal to the third frequency.
The control unit 202 is configured to receive a baseband signal corresponding to the generated first frequency of operation from the FMCW radar on chip subsystem 204. The control unit 202 is configured to evaluate signal strength of the received baseband signal strength using one or more signal processing techniques. The one or more signal processing techniques may include, for example, but not limited to: a Pulse Compression, a Moving Target Indication (MTI), a Clutter Rejection, a Synthetic Aperture Radar (SAR), and the like.
Further, the control unit 202 is configured to detect the at least one target 132 based on received baseband signal and the evaluated signal strength. The control unit 202 is configured to determine whether a signal quality of the baseband signal meets a pre-defined signal quality criteria based on the detected at least one target and using at least one of a data driven model and predefined rules. In an example embodiment, the data driven model may be any artificial intelligence based or machine learning based model. The pre-defined signal criteria may include, for example, but not limited to, at least one of validating number of targets detected, validating a type of targets detected and validating environmental requirements. The control unit 202 may be configured with a pre-defined criteria for the minimum and maximum number of targets expected to be detected in a given scenario. Thus, helps in verifying that the radar 200 in detecting the expected number of targets and may alert operators, if there are any discrepancies.
The control unit 202 detects specific types of targets based on their radar cross-section (RCS), size, speed, and other characteristics. A pre-defined criteria may be used to validate that the detected targets match the expected types based on these characteristics. Further, performance may be affected by various environmental factors such as weather conditions, terrain, and electromagnetic interference. The pre-defined criteria may be used to validate that the control unit 202 which meets the required performance specifications under different environmental conditions.
The control unit 202 is configured to determine an updated set of frequency of operation for operating the FMCW radar on chip subsystem 204, if the determined signal quality does not meet the pre-defined signal quality criteria. Further, the control unit 202 is configured to generate an updated first set of control signals for the chirp signal to be transmitted based on determined updated set of frequency of operation. Furthermore, generate an updated second set of control signals for controlling the updated set of frequency of operation. The control unit 202 is further configured to tune the FMCW radar on chip subsystem 204 and the front-end subsystem 222 to the updated set of frequency of operation using the corresponding generated updated first set of control signals and the updated second set of control signals.
Further, the control unit 202 is configured to transmit the generated plurality of control signals to the radar subsystem 204.
In an embodiment, the radar subsystem 204 is communicatively coupled to the control unit 202 via a communication network (not shown). The communication network may be wired or wireless network. The radar subsystem 204 is tuned to operate in the frequency range of f1’ to f2’ and does not generate any undesirable harmonics. Thus, such harmonic FMCW radar systems 200 may be suitable for a semiconductor chip implementation, where multiple harmonics do not circulate and interact with each other inside the chip, degrading performance. The input frequency range of f1’ to f2’ is applied at the radar-on-chip side 204, and the FEM 222-1 may be configured to shift the frequency range to f1 to f2. The input frequencies applied to the receiver end are in the range of f1 to f2 and shifted to f1’ to f2’. The output frequency of the FEM 222-1, existing between f1 and f2 may be next divided by the frequency divider 224 (for example, but not limited to, a regenerative divider, and the like).
In another embodiment, the frequency divider 224 may be integrated within the radar subsystem 204. The divided signal in the frequency range of f1/2 to f2/2 also known as “RF out”, is transmitted using the transmitter subsystem 228, and the transmission antenna 232-1 with some implementations requiring additional power amplification. The signal impinges upon the tag 106 worn by the target 132. The tag 106 generates the second harmonic and transmits it back to the harmonic FMCW radar system 200. The new frequency range, due to multiplication, is from f1 to f2.
In an embodiment, when this signal “RF in” is received by the receiving antenna 232-2 along with the receiving subsystem 230, it may be filtered (optionally) using the bandpass filter 226. Further, the FEM 222-1 may be configured to shift the received signal from f1-f2 to f1’-f2’. Any mixing products, as shown in FIG. 2A, are rejected due to the tuned nature of the FMCW radar-on-chip 204.The front-end module 222-1 may be configured for processing incoming radar signals.
The FEM 222-1 may use, for example, artificial intelligence (AI) algorithms to perform tasks such as signal preprocessing, target detection, and the like. In signal preprocessing, the frontend module 222-1 may apply techniques which include, but not limited to: noise reduction, clutter suppression, signal enhancement, and the like to improve the quality of the radar signals. Thus, facilitates extracting information from the received signals and reduces the impact of environmental factors or interference. For target detection, AI algorithms may be used to identify potential targets in the radar data. This may involve detecting peaks in the signal that indicate the presence of a target or using machine learning algorithms to classify radar returns as either targets or clutter.
In an embodiment, the ability to tune the frequency of operation using fTXLO and fRXLO as offsets in the FEM 222-1, allows the radar system 204 to operate at a suitable frequency where the propagation due to a type of snow (dry vs. wet) and debris is optimal. The determination is made by the control unit 202, which evaluates the signal quality (after digitization by the ADC) and tunes the radar system 204 operational frequency to an optimal value using the FMCW radar on the chip 204 and the Frequency control instruction given to the FEM module 222-1.
The transmit subsystem 228 comprises a transmit antenna configured to transmit the divided output offset frequency as a transmit signal to at least one target via a transmit antenna 232-1. The receiver subsystem 230 may receive the at least one input offset frequency as a received signal from the at least one target via a receive antenna 232-2. The received at least one input offset frequency comprises the third frequency value and the fourth frequency value. The output offset frequency may be f1 to f2, where f1 may be third frequency and f2 may be fourth frequency. The divided output offset frequency may be f1/2 to f2/2.
Further, the receiver subsystem 230 may transmit the received at least one input offset frequency to a receiver port of the front-end module 222-1 as an input signal to generate a first frequency of operation based on the received at least one input offset frequency from the receiver subsystem 230 and the generated second set of control signal. The first frequency of operation ranges between the first frequency and the second frequency, and where the third frequency value and the fourth frequency value are shifted to the first frequency and the second frequency. In case the radar on chip subsystem 204 is a CW radar subsystem, then the second frequency may be equal to the first frequency and the fourth frequency may be equal to the third frequency, wherein this system can also support the continuous wave (CW) mode of operation in addition to the FMCW mode of operation.
FIG. 3A-3B is a block diagram of an exemplary front-end subsystem 222, in accordance with an embodiment of the present disclosure. The harmonic FMCW radar system 300 comprises a control unit 202 (similar to those shown in FIG.2). At the transmitter side, the front-end subsystem 222 comprises a first transmit signal 302-1 received from the radar subsystem 204 as an input signal, a first filter 304-1, a first intermediate frequency (IF) amplifier 306-1, a transmitter side mixer module 308-1, a power amplifier 310-1, a second filter 312-1, and a transmit antenna 314-1. At the receiver side, the front-end subsystem 222 comprises a first receive output signal 302-2, a third filter 304-2, a second intermediate frequency (IF) amplifier 306-2, a receiver side mixer module 308-2, a low-noise amplifier (LNA) 310-2, a fourth filter 312-2, and a receive antenna 314-2.
The front-end module 222-1 further comprises a frequency generation module 316 configured to generate a transmit frequency control signal (TXLO) and a receive frequency control signal (RXLO) based on the generated second set of control signals. The transmitter side mixer module 308-1 is configured to generate the at least one output offset frequency by mixing the generated transmit frequency control signal (TXLO) with the base frequency of operation. The receiver side mixer module 308-2 is configured to generate the first frequency of operation by mixing the receive frequency control signal (RXLO) with the received at least one input offset frequency.
In one embodiment, the transmitter side mixer module 308-1 multiplies a signal TXLO with the input signals (f1’ to f2’) to generate the offset output (f1 to f2).
Specifically, f1 = f1’ +fTXLO -------- Equation (1), and
f2=f2’+fTXLO -------- Equation (2)
Where, fTXLO is the frequency of the signal TXLO. Since several additional frequency components may be produced during multiplication, the amplifiers and filters shown in FIG. 3A, may help in selecting the desired signals from f1 to f2. Similarly, the receiver side mixer module 308-2, which uses fRXLO to shift the frequency of the received input signal (f1-f2) to a new frequency (f1’-f2’) and cleans up the spectrum using amplifiers and filters. Both TXLO and RXLO signals are generated using the frequency generation module 316 such as for example, but not limited to, a phase locked loop (PLL) which obtains the frequency control instruction from the control unit 202.
In another embodiment, the FEM 222-1, or parts of the front-end subsystem 222, may be implemented inside the FMCW radar-on-chip 204 without impacting coupling between signals as it will be an interface (peripheral) block which may be segregated from the rest of the chip.
FIG. 4 is a circuit diagram of an exemplary transponder 400, in accordance with embodiment of the present disclosure. The transponder 400 may be associated with the at least one target 132. The transponder 400 may be configured to generate the at least one input offset frequency in response to the divided output offset frequency received from the transmit subsystem 228.
The transponder 400 is similar to the transponder 106 shown in FIG. 1A. The transponder 400 comprises a receive transponder subsystem 404 configured to receive the divided output offset frequency from the transmit subsystem 228 via a receive antenna 402. The receive antenna 402 may be tuned to the divided output offset frequency. The transponder 400 is further configured to transmit the divided output offset frequency to a diode bridge 406, where the diode bridge may be configured to generate a full wave rectified signal as an output corresponding to the divided output offset frequency.
The transponder 400 further comprises a signal splitter 408 configured to split the generated full wave rectified signal into at least two paths. One path comprises a low pass filter (not shown in FIG. 4) to generate a filtered signal for harvesting a DC voltage, (VDD-408-1) and the second path comprises a second harmonic extractor array 408-2 configured to extract a second harmonic frequency from the generated full wave rectified signal.
The transponder 400 comprises a radio frequency (RF) amplifier 414 communicatively coupled to the second harmonic extractor array 408-2 and is configured to generate the at least one input offset frequency based on the extracted second harmonic data. The RF amplifier 414 is powered by the DC voltage (VDD) 408-1. Further, a transmit transponder subsystem 416 of the transponder 400 is configured to transmit the generated at least one input offset frequency to the receiver subsystem 230 via a transmit antenna 418. The transmit antenna 418 is tuned to the first frequency of operation.
The transponder 400 comprises a reserve battery 412 for back up operation if the energy harvested is determined to be insufficient. The transponder 400 comprises a power supply control unit 410 configured to determine an optimal power source to be used for generating the filtered signal based on a status of the reserve battery 412. The optimal power source is selected between one of the reserve battery 412 and an incident RF energy source corresponding to the received divided output offset frequency.
In an embodiment, the transponder 400 consists of the receiving antenna 402 coupled to the receive transponder subsystem 404 and a transmitting antenna 418 coupled to the transmitting transponder subsystem 416 tuned between f1/2-f2/2 and f1-f2, respectively. When the incident energy is received, which is full wave rectified with a diode bridge circuit 406. The bridge’s output is split into two paths, with one path low pass filtered to harvest a DC voltage, VDD 408-1. The other path extracts the second harmonic, using a harmonic extractor 408-2 (a resonant circuit in one embodiment) and applies it to the input of the RF amplifier 414, powered by VDD 408-1. Thus, allowing the transponder 400 to generate a strong return signal which is picked up by the harmonic FMCW radar 200.
FIG. 5 is a block diagram illustrating an exemplary apparatus for a harmonic frequency-modulated continuous wave (FMCW) radar, in accordance with an embodiment of the present disclosure. In an example embodiment, the apparatus 500 may be one of a control unit 202, or a radar subsystem 204 or a front-end subsystem 222 or a combination of the control unit 202, the radar subsystem 204 and the front-end subsystem 222. The apparatus 500 comprises one or more hardware processors 502, a memory 504 and a storage unit 506. The one or more hardware processors 502, the memory 504 and the storage unit 506 are communicatively coupled through a system bus 508 or any similar mechanism. The memory 504 comprises the plurality of modules 510 in the form of programmable instructions executable by the one or more hardware processors 502.
The one or more hardware processors 502, as used herein, means any type of computational circuit, such as, but not limited to, a microprocessor unit, microcontroller, complex instruction set computing microprocessor unit, reduced instruction set computing microprocessor unit, very long instruction word microprocessor unit, explicitly parallel instruction computing microprocessor unit, graphics processing unit, digital signal processing unit, or any other type of processing circuit. The one or more hardware processors 502 may also include embedded controllers, such as generic or programmable logic devices or arrays, application specific integrated circuits, single-chip computers, and the like.
The memory 504 may be non-transitory volatile memory and non-volatile memory. The memory 504 may be coupled for communication with the one or more hardware processors 502, such as being a computer-readable storage medium. The one or more hardware processors 502 may execute machine-readable instructions and/or source code stored in the memory 504. A variety of machine-readable instructions may be stored in and accessed from the memory 504. The memory 504 may include any suitable elements for storing data and machine-readable instructions, such as read only memory, random access memory, erasable programmable read only memory, electrically erasable programmable read only memory, a hard drive, a removable media drive for handling compact disks, digital video disks, diskettes, magnetic tape cartridges, memory cards, and the like. In the present embodiment, the memory 504 includes the plurality of modules 510 stored in the form of machine-readable instructions on any of the above-mentioned storage media and may be in communication with and executed by the one or more hardware processors 502.
The storage unit 506 may be a cloud storage or a local file directory within a remote server. The storage unit 506 may store the set of radar parameters, the first set of control signals, the second set of control signals, a chirp signal, the output offset frequency, the base frequency and the like.
In an example embodiment, the control unit 202 is configured to determine a set of radar parameters corresponding to a chirp signal to be transmitted through a user interface where the user selects such parameters to determine specific characteristics of the target 132 such as range and velocity to a certain accuracy and resolution. In some embodiments, the set of radar parameters may be automatically determined by the control unit 202. The set of radar parameters may include at least one of the start frequency (fstart) and stop frequency (fstop) of the chirp signal, a ramp rate of the chirp signal, bandwidth information of the chirp signal and the like. In an embodiment, the start frequency (fstart) of the chirp signal corresponds to initial frequency of the chirp signal at the beginning of the transmission. This parameter determines starting point of the "chirp." The bandwidth information of the chirp signal specifies a total range of frequencies covered by the chirp. A wider bandwidth allows the harmonic FMCW radar system 200 to detect the one or more targets 132 with a better resolution of speeds and distances.
Further, the processor 502 is configured to generate a first set of control signals for a chirp signal to be transmitted based on a set of radar parameters. Furthermore, the processor 502 is configured to generate a second set of control signals for controlling a frequency of operation based on a set of signal parameters. The processor 502 is further configured to transmit the generated first set of control signals to a FMCW radar-on-chip subsystem 204. Further, processor 502 is configured to transmit the generated second set of control signals to a front-end subsystem 222. The FMCW radar 204 on chip subsystem, communicatively coupled to the control unit 202, comprises a local oscillator 206 configured to operate at a base frequency of operation required for transmission of the chirp signal based on the first set of control signals. The base frequency of operation ranges between a first frequency and a second frequency. The base frequency of operation is set based on the first set of control signals.
Further, the front-end subsystem 222 communicatively coupled to the FMCW radar on chip subsystem 204 and the control unit 202. The front-end subsystem 222 comprises a front-end module 222-1 configured to generate at least one output offset frequency based on the base frequency of operation and the generated second set of control signals. The at least one output offset frequency comprises a third frequency value and a fourth frequency value, and where the first frequency and the second frequency are shifted to the third frequency value and the fourth frequency value.
The front-end subsystem 222 includes a frequency divider module 224 configured to divide the generated at least one output offset frequency. At a transmitter subsystem 228 the processor 502 is configured to communicatively coupled to the frequency divider module 224, where the processor 502 is configured to transmit the divided output offset frequency as a transmit signal to at least one target via a transmit antenna 232-1. At a receiver subsystem 230, the processor 502 is configured to receive the at least one input offset frequency as a received signal from the at least one target via a receive antenna 232-2. Further, the received at least one input offset frequency comprises the third frequency value and the fourth frequency value. The receiver subsystem 230 transmits the received at least one input offset frequency to a receiver port of the front-end module 222-1 as an input signal.
The front-end module 222-1 is configured to generate a first frequency of operation based on the received at least one input offset frequency from the receiver subsystem 230 and the generated second set of control signals. The first frequency of operation ranges between the first frequency and the second frequency, and where the third frequency value and the fourth frequency value are shifted to the first frequency and the second frequency.
FIG. 6 is a flow diagram illustrating an exemplary method 600 for operating a harmonic FMCW radar 200, in accordance with embodiment of the present disclosure. At step 602, the method 600 includes generating, by a processor 502, a first set of control signals for a chirp signal to be transmitted based on a set of radar parameters. At step 604, the method 600 includes generating, by the processor 502, a second set of control signals for controlling a frequency of operation based on a set of signal parameters. At step 606, the method 600 includes operating, by the FMCW radar on chip subsystem 204, at a base frequency of operation required for transmission of the chirp signal based on the first set of control signals. The base frequency of operation ranges between a first frequency and a second frequency based on the first set of control signals.
At step 608, the method 600 includes generating, by a front-end subsystem 222, at least one output offset frequency based on the base frequency of operation and the generated second set of control signals. The at least one output offset frequency comprises a third frequency value and a fourth frequency value. The first frequency and the second frequency are shifted to the third frequency value and the fourth frequency value.
At step 610, the method 600 includes dividing, by a frequency divider module 224, the generated at least one output offset frequency. At step 612, the method 600 includes transmitting, by the front-end subsystem 222, the divided output offset frequency as a transmit signal to at least one target via a transmit antenna 232-1. At step 614, the method 600 includes receiving, by the front-end subsystem 222, the at least one input offset frequency as a received signal from the at least one target via a receive antenna. The received at least one input offset frequency comprises the third frequency value and the fourth frequency value. At step 616, the method 600 includes generating, by the front-end subsystem 222, a first frequency of operation based on the received at least one input offset frequency and the generated second set of control signals. The first frequency of operation ranges between the first frequency and the second frequency, and where the third frequency value and the fourth frequency value are shifted to the first frequency and the second frequency.
FIG. 7 is a flow diagram illustrating an exemplary method 700 for operating a harmonic FMCW radar 200, in accordance with embodiment of the present disclosure. At, step 704, setting, by the processor 502, the frequency of operation (f1’ to f2’) and the first set of radar parameters and translating, by the processor 502, the operational frequency range to f1-f2. At step 706, transmitting, by the processor 502, a FMCW radar signal. At step 708, evaluating, by the processor 502, a signal strength of the received baseband signal strength using one or more signal processing techniques. At step 710, detecting, by the processor 502, the at least one target based on received baseband signal and the evaluated signal strength. At step 712, determining, by the processor 502, whether a signal quality of the baseband signal meets a pre-defined signal quality criteria based on the detected at least one target and using at least one of a data driven model and predefined rules. The pre-defined signal criteria comprise at least one of validating number of targets detected, validating a type of targets detected and validating environmental requirements.
At step 716, determining, by the processor 502, whether the received baseband signal has low signal to noise ratio and hence, low signal quality caused by attenuation due to propagation, interference or deliberate jamming from other radio frequency sources. Further, determining, by the processor 502, an updated set of frequency of operation for operating the FMCW radar on chip subsystem 204, if the determined signal quality does not meet the pre-defined signal quality criteria.
At step 718, generating, by the processor 502, an updated first set of control signals for the chirp signal to be transmitted based on determined updated set of frequency of operation. Further, generating, by the processor 502, an updated second set of control signals for controlling the updated set of frequency of operation. Finally, tuning, by the processor 502, the FMCW radar on chip subsystem 204 and the front-end subsystem 222 to the updated set of frequency of operation using the corresponding generated updated first set of control signals and the updated second set of control signals.
The FMCW radar 204 of the present invention provides better range resolution by using frequency modulation to encode the transmitted signal, allowing for more precise distance measurements. The FMCW radar 204 of the present invention may achieve better interference rejection compared to other radar systems, by using frequency modulation the FMCW radar 204 may distinguish between signals reflected from the target and those from other sources, such as clutter or noise.
FIG. 8 is an exemplary graphical representation of attenuation characteristics of radio or radar signals through snow quantified by the penetration depth in, accordance with an embodiment of the present disclosure.
As shown in FIG. 8, the penetration depth of radar signals under snow, which is critical to the rescue of a trapped person, is a strong function of frequency and the type of snow (dry or wet). In general, higher frequencies and wetter snow, both reduce the penetration depth. In an avalanche debris field, the presence of rocks and trees makes it more difficult to clearly predict the propagation characteristics, adding an unknown element to signal propagation.
Thus, penetration depth of radar signals under snow depends on several factors, including the frequency of the radar signal, the type of snow, and the properties of the underlying material (such as soil or ice). For example, in dry snow conditions, radar signals with frequencies in the range of 100 MHz to 1 GHz may penetrate several meters or more. However, in wet snow or near the melting point, the penetration depth may be significantly reduced.
The radars implementing FMCW radar technology along with harmonics are used in such a way that the harmonics may be segregated inside a semiconductor chip, inhibiting signal coupling. Additionally, a method to enable optimal propagation through snow under varying conditions of weather, snow type (dry or wet) and the composition of debris (rocks, snow and the like.) is disclosed.
The radar signals may penetrate deeper into dense materials such as ice or compacted or dry snow compared to loose, dry or wet snow. Additionally, the presence of air gaps, ice layers, or water pockets within the snowpack may affect the penetration depth. The radar system 200 is used to estimate the thickness and density of the snowpack based on the penetration depth of the radar signals.
The embodiments herein may comprise hardware and software elements. The embodiments that are implemented in software include but are not limited to, firmware, resident software, microcode, a. The functions performed by various modules described herein may be implemented in other modules or combinations of other modules. For the purposes of this description, a computer-usable or computer readable medium may be any apparatus that may comprise, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that ongoing technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries may be defined so long as the specified functions and relationships thereof are appropriately performed. Alternatives (including equivalents, extensions, variations, deviations, and the like, of those described herein) will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Such alternatives fall within the scope and spirit of the disclosed embodiments. Also, the words “comprising,” “having,” “containing,” and “including,” and other similar forms are intended to be equivalent in meaning and be open-ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present invention are intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

, Claims:We claim:
1. A radar (200, 300) comprising:
a control unit (202) configured to:
generate a first set of control signals for a chirp signal to be transmitted based on a set of radar parameters;
generate a second set of control signals for controlling a frequency of operation based on a set of signal parameters;
transmit the generated first set of control signals to a radar-on-chip subsystem (204); and
transmit the generated second set of control signals to a front-end subsystem (222);
the radar on chip subsystem (204), communicatively coupled to the control unit (202), comprises:
a local oscillator (206) configured to:
operate at a base frequency of operation required for transmission of the chirp signal based on the first set of control signals, wherein the base frequency of operation ranges between a first frequency and a second frequency based on the first set of control signals;
the front-end subsystem (222) communicatively coupled to the radar on chip subsystem (204) and the control unit (202), wherein the front-end subsystem (222) comprises:
a front-end module (222-1) configured to generate at least one output offset frequency based on the base frequency of operation and the generated second set of control signals, wherein the at least one output offset frequency comprises a third frequency value and a fourth frequency value, and wherein the first frequency and the second frequency are shifted to the third frequency value and the fourth frequency value;
a frequency divider module (222-4) communicatively coupled to the radar on chip subsystem (204), a configured to divide the generated at least one output offset frequency;
a transmitter subsystem (228) communicatively coupled to the frequency divider module (224), wherein the transmitter subsystem (228) is configured to transmit the divided output offset frequency as a transmit signal to at least one target via a transmit antenna (232-1); and
a receiver subsystem (230) configured to:
receive the at least one input offset frequency as a received signal from the at least one target via a receive antenna (232-2), wherein the received at least one input offset frequency comprises the third frequency value and the fourth frequency value; and
transmit the received at least one input offset frequency to a receiver port of the front-end module (222-1) as an input signal; and
wherein the front-end module (222-1) is configured to generate a first frequency of operation based on the received at least one input offset frequency from the receiver subsystem (230) and the generated second set of control signals, and wherein the first frequency of operation ranges between the first frequency and the second frequency, and wherein the third frequency value and the fourth frequency value are shifted to the first frequency and the second frequency.

2. The radar (200,300) as claimed in claim 1, wherein the control unit (202) is further configured to:
receive a baseband signal corresponding to the generated first frequency of operation from the radar on chip subsystem (204);
evaluate signal strength of the received baseband signal strength using one or more signal processing techniques;
detecting the at least one target based on received baseband signal and the evaluated signal strength;
determining whether a signal quality of the baseband signal meets a pre-defined signal quality criteria based on the detected at least one target and using at least one of a data driven model and predefined rules, wherein the pre-defined signal criteria comprise at least one of validating number of targets detected, validating a type of targets detected and validating environmental requirements;
determining an updated set of frequency of operation for operating the radar on chip subsystem (204) if the determined signal quality does not meet the pre-defined signal quality criteria;
generate an updated first set of control signals for the chirp signal to be transmitted based on determined updated set of frequency of operation;
generate an updated second set of control signals for controlling the updated set of frequency of operation; and
tuning the FMCW radar on chip subsystem (204) and the front-end subsystem (222) to the updated set of frequency of operation using the corresponding generated updated first set of control signals and the updated second set of control signals.

3. The radar (200,300) as claimed in claim 1, wherein the control unit (202) is further configured to generate an alarm signal corresponding to the detected at least one target.

4. The radar (200,300) as claimed in claim 1, wherein the front-end module (222-1) comprises:
a frequency generation module (316) configured to generate a transmit frequency control signal (TXLO) and a receive frequency control signal (RXLO) based on the generated second set of control signals;
a transmitter side mixer module (308-1) configured to generate the at least one output offset frequency by mixing the generated transmit frequency control signal (TXLO) with the base frequency of operation; and
a receiver side mixer module (308-2) configured to generate the first frequency of operation by mixing the receive frequency control signal (RXLO) with the received at least one input offset frequency.

5. The radar (200,300) as claimed in claim 1, further comprises:
a transponder (400) associated with the at least one target (132), wherein the transponder (400) is configured to generate the at least one input offset frequency in response to the divided output offset frequency received from the transmit subsystem.

6. The radar (200,300) as claimed in claim 4, wherein the transponder (400) comprises:
a receive transponder subsystem (404) configured to receive the divided output offset frequency from the transmit subsystem (228) via a receive antenna (402), wherein the receive antenna is tuned to the divided output offset frequency; and
transmit the divided output offset frequency to a diode bridge (406);
the diode bridge (406) configured to generate a full wave rectified signal as an output corresponding to the divided output offset frequency;
a signal splitter (408) configured to split the generated full wave rectified signal into at least two paths, wherein one path comprises a low pass filter (408-1) to generate a filtered signal for harvesting a DC voltage, (VDD) and the second path comprises a second harmonic extractor array (408-2) configured to extract a second harmonic frequency from the generated full wave rectified signal;
a radio-frequency (RF) amplifier (414) communicatively coupled to the second harmonic extractor array (408-2), wherein the RF amplifier (414) is configured to generate the at least one input offset frequency based on the extracted second harmonic data, wherein the RF amplifier (414) is powered by the DC voltage (VDD); and
a transmit transponder subsystem (416) configured to transmit the generated at least one input offset frequency to the receiver subsystem (230) via a transmit antenna (418), wherein the transmit antenna (418) is tuned to the first frequency of operation.

7. The radar (200, 300) as claimed in claim 6, wherein the transponder (400) comprises a reserve battery (412) for back up operation if the energy harvested is determined to be insufficient.

8. The radar (200, 300) as claimed in claim 6, wherein the power supply control network (410) is further configured to:
determine an optimal power source to be used for generating the filtered signal based on a status of the reserve battery (412), wherein the optimal power source is selected between one of the reserve battery (412) and an incident RF energy source corresponding to the received divided output offset frequency.

9. The radar (200, 300) as claimed in claim 1, wherein the radar on chip subsystem (204) corresponds to one of a frequency-modulated continuous wave (FMCW) radar subsystem and a continuous wave (CW) radar subsystem, and wherein if radar on chip subsystem (204) corresponds to the CW radar subsystem, then the second frequency may be equal to the first frequency and the fourth frequency may be equal to the third frequency.

10. A method (600) for operating a radar, the method (600) comprising:
generating, by a processor (502), a first set of control signals for a chirp signal to be transmitted based on a set of radar parameters;
generating, by the processor (502), a second set of control signals for controlling a frequency of operation based on a set of signal parameters;
operating, by the radar on chip subsystem (204), at a base frequency of operation required for transmission of the chirp signal based on the first set of control signals, wherein the base frequency of operation ranges between a first frequency and a second frequency based on the first set of control signals;
generating, by a front-end subsystem (222), at least one output offset frequency based on the base frequency of operation and the generated second set of control signals, wherein the at least one output offset frequency comprises a third frequency value and a fourth frequency value, and wherein the first frequency and the second frequency are shifted to the third frequency value and the fourth frequency value;
dividing, by a frequency divider module (224) coupled to the processor (502), the generated at least one output offset frequency;
transmitting, by the front-end subsystem (222), the divided output offset frequency as a transmit signal to at least one target (132) via a transmit antenna (232-1);
receiving, by the front-end subsystem (222), the at least one input offset frequency as a received signal from the at least one target (132) via a receive antenna (232-2), wherein the received at least one input offset frequency comprises the third frequency value and the fourth frequency value; and
generating, by the front-end subsystem (502), a first frequency of operation based on the received at least one input offset frequency and the generated second set of control signals, and wherein the first frequency of operation ranges between the first frequency and the second frequency, and wherein the third frequency value and the fourth frequency value are shifted to the first frequency and the second frequency.

11. The method (600) as claimed in claim 10, further comprising:
receiving, by the processor (502), a baseband signal corresponding to the generated first frequency of operation from the radar on chip subsystem (204);
evaluating, by the processor (502), a signal strength of the received baseband signal strength using one or more signal processing techniques;
detecting, by the processor (502), the at least one target based on received baseband signal and the evaluated signal strength;
determining, by the processor (502), whether a signal quality of the baseband signal meets a pre-defined signal quality criteria based on the detected at least one target and using at least one of a data driven model and predefined rules, wherein the pre-defined signal criteria comprise at least one of validating number of targets detected, validating a type of targets detected and validating environmental requirements;
determining, by the processor (502), whether the received baseband signal has low signal to noise ratio and hence, low signal quality caused by attenuation due to propagation, interference or deliberate jamming from other radio frequency sources;
determining, by the processor (502), an updated set of frequency of operation for operating the radar on chip subsystem (204) if the determined signal quality does not meet the pre-defined signal quality criteria;
generating, by the processor (502), an updated first set of control signals for the chirp signal to be transmitted based on determined updated set of frequency of operation;
generating, by the processor (502), an updated second set of control signals for controlling the updated set of frequency of operation; and
tuning, by the processor (502), the radar on chip subsystem (204) and the front-end subsystem (222) to the updated set of frequency of operation using the corresponding generated updated first set of control signals and the updated second set of control signals.

12. The method (600) as claimed in claim 10, further comprising:
generating, by the processor (502), an alarm signal corresponding to the detected at least one target.

13. The method (600) as claimed in claim 10, further comprising:
generating, by the front-end subsystem (222), a transmit frequency control signal (TXLO) and a receive frequency control signal (RXLO) based on the generated second set of control signals;
generating, by the front-end subsystem (222), the at least one output offset frequency by mixing the generated transmit frequency control signal (TXLO) with the base frequency of operation; and
generating, by the front-end subsystem (222), the first frequency of operation by mixing the receive frequency control signal (RXLO) with the received at least one input offset frequency.

14. The method (600) as claimed in claim 10, further comprises:
generating, by a transponder (400), the at least one input offset frequency in response to the divided output offset frequency.

15. The method (600) as claimed in claim 14, wherein generating the at least one input offset frequency in response to the divided output offset frequency comprises:
receiving, by the transponder (400), the divided output offset frequency from a transmit subsystem via a receive antenna, wherein the receive antenna is tuned to the divided output offset frequency;
generating, by the transponder (400), a full wave rectified signal as an output corresponding to the divided output offset frequency;
splitting, by the transponder (400), the generated full wave rectified signal into at least two paths, wherein one path generates a filtered signal for harvesting a DC voltage, (VDD) and the second path extracts a second harmonic data from the generated full wave rectified signal;
generating, by the transponder (400), the at least one input offset frequency based on the extracted second harmonic data; and
transmitting, by the transponder (400), the generated at least one input offset frequency to a receiver subsystem via a transmit antenna.

16. The method (600) as claimed in claim 15, further comprises:
determining, by the transponder (400), an optimal power source to be used for generating the filtered signal based on a status of harvested energy from the incident RF energy source and the reserve battery, wherein the optimal power source is selected between one of the reserve battery and an incident RF energy source corresponding to the received divided output offset frequency.

Dated this 5th day of April 2024

Name: Sanath MV
Patent Agent No.5004
PrasaIP