TECHNICAL FIELD The present invention generally relates to electronics circuits. The invention, more particularly, relates to radio frequency circuit design.
BACKGROUND Low loss and low noise figure receivers are always required for communication purposes or sensing purposes. Especially for jamming purposes, a broadband receiver is required for sensing the signal to be jammed. Instead of broadband sensing, multiband sensing is a good choice because in multiband sensing parallel receivers can be implemented to improve intercept time.
When a new band comes into the picture for communication and if it is required to be jammed, PA designers can easily supply Power Amplifier for that band in less time. Multiband sensing can be done by a broadband receiver bypassing the RF signal first through a power divider and then subsequently through the Bandpass filters.
There are many conventional solutions exist, for example, one of a conventional solution is proposed U9660691 titled "Antenna Interface circuit with Quadplexer" discloses a technique for supporting data transmission on multiple bands for carrier aggregation. The prior art main focus is on carrier aggregation technique for improvement of data rate in the communication system. Image 110 of the prior art deals with band separation as Low, mid and high for carrier aggregation.
Another conventional solution is proposed in CN205621822 titled "High isolation low pass band pass Triplexer" discloses a high isolation low pass band -pass triplexer, including low pass filter (5), two band pass filter (6, 7) and transmission line (8), wherein two minor matters

of opening a way in low pass filter (5) produce the transmission zero that two frequencies are band pass filter (6,7) central frequency respectively, and it is short -circuit state to make its central frequency signal at two band pass filter at the input department of low pass filter (5), be equipped with setpoint p1 on transmission line (8), P2, P3, P1 to p3 distance wherein, P2 corresponds band pass filter central frequency's quarter wavelength respectively to the p3 distance, invert according to the quarter wavelength impedance, band pass filter (6, 7). The central frequency signal at p1, P2 is the open -circuit condition respectively, convenient each low pass band pass filter that independently designs of this triplexer, make it each other not influence, the design cycle can be shortened and design efficiency is improved, and this structure can obtain high isolation.
[0006] In another conventional solution proposed in CN204375881
titled “Plane lower passband leads to triplexer” discloses a kind of plane lower passband and leads to triplexer, comprise low pass filter (11), two band pass filters (12), (13) and transmission lines (14), two minor matters wherein in low pass filter (11) load resonator and produce the transmission zero that two frequencies are respectively band pass filter (12) and (13) centre frequency, make it be short-circuit condition in the center frequency signal of input end two band pass filters of low pass filter (11); Transmission line (14) is provided with anchor point p1, p2, p3, the wherein quarter-wave of p1 to p3 distance, the corresponding band pass filter centre frequency of p2 to p3 distance difference, be inverted according to quarter-wave impedance, band pass filter (12) is respectively open-circuit condition with the center frequency signal of (13) at p1, p2, this triplexer facilitates each lower passband bandpass filter of independent design, make it be independent of each other, the design cycle can be shortened and improve design efficiency.

[0007] In another conventional solution proposed in US2016365889
titled “Antenna Interface circuit with Quadplexer” is based on interfacing to the antenna for communication for which prior art only used diplexer, Triplexer or Quadplexer.
[0008] In another conventional solution proposed in US7376440B2
titled “N-plexer system and method for use in a wireless communication device” disclose a wireless communication device that comprises an N-plexer, that is, a multi-band device, connected to a single antenna for receiving multiple communication bands on the single antenna. It can be separated in two part of the invention. In one part prior art focuses on the improvement of the wireless communication system by using N-plexer and other part focuses on design and fabrication of N number of high isolation and high Q FBAR band pass filters so the inventor claimed on FBAR filter design and fabrication not on design.
[0009] In another conventional solution proposed in CN104836618
(A) titled “Bidirectional Pentaplexer system and method” discloses a bidirectional pentaplex system is connected to a machine room. The prior art deals with optical signals for receiving and transmitting. The prior art Pentaplexer system is based on a reflection of light for their multiplexing purpose.
[0010] However, none of the conventionally available systems are
providing a solution that prevents a loss during a Multiband sensing. Thus, there is a need for an architecture to reduce the loss during Multiband sensing.

SUMMARY OF INVENTION
[0011] This summary is provided to disclose a method and N-
plexer based receiver for spectrum sensing for LTE jammer application that works simultaneously in multiple bands having low N.F, low insertion loss, and low insertion low interference between multiple frequency bands. This summary is neither intended to identify essential features of the present invention nor is it intended for use in determining or limiting the scope of the present invention.
[0012] In an embodiment, the present invention describes a method
for N-plexer based receiver architecture for spectrum sensing. The method comprising steps of receiving, by a signal conditioning circuit block, a broadband radio frequency (RF signal) transmitted from a transmitter. The method further includes splitting, by a splitter block the received broadband RF signals into N-sub-band RF signals with disjoint frequency characteristics. The splitting criteria of the received broadband RF signals are based on the value of the required stages. The number of stages required is calculated. Calculation of the stages depends on the number of bands used for the communication purpose, for jamming applications. Further, all the N bands are sensed and then jammed.
[0013] In another embodiment, the present invention describes an
N-plexer based receiver architecture for spectrum sensing comprising a signal conditioning circuit block configured to receive a broadband radio frequency (RF signal) transmitted from a transmitter. The system further includes a splitter block configured to split the received broadband RF signals into N-sub-band RF signals with disjoint frequency characteristics. The disjoint frequency characteristics means multiple band that are non-

overlapping in frequency. The splitting criteria of the received broadband RF signals are based on the value of the required stages.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0014] The detailed description is described with reference to the
accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and modules.
[0015] Fig. 1 illustrates a block diagram depicting an N-plexer
(Pentaplexer) chain with a signal conditioning block, according to an embodiment of the present invention.
[0016] Fig. 2 illustrates a block diagram depicting a receiver chain,
according to an exemplary implementation of the present invention.
[0017] Fig. 3 illustrates a schematic diagram depicting an N-plexer
(Pentaplexer) describing Quadplexer and Diplexer network, according to an exemplary implementation of the present invention.
[0018] Fig. 4 illustrates a schematic diagram depicting a stage
calculation and N-plexer splitting criterion, according to an exemplary implementation of the present invention.
[0019] Fig. 5 illustrates a schematic diagram depicting a Band
splitting criterion using the described parameters.
[0020] Fig. 6 illustrates a schematic diagram depicting a unit cell of
an N-plexer, according to an embodiment of the present invention.

[0021] Fig. 7 illustrates a schematic diagram depicting an RF
network of the unit cell, according to an embodiment of the present invention.
[0022] Fig. 8 illustrates a block diagram depicting a connection of
unit cell to design an N-plexer, according to an embodiment of the present invention.
[0023] Fig. 9 illustrates a block diagram depicting an N-plexer for
multi-band receiving purpose, according to an embodiment of the present invention.
[0024] Fig. 10 illustrates a block diagram depicting an N-plexer for
transmitting a combined multiband signal, according to an embodiment of the present invention.
[0025] Fig. 11 illustrates a block diagram for the process involved in
designing an N-plexer, according to an exemplary implementation of the present invention.
[0026] Fig. 12 illustrates a method for N-plexer based receiver
architecture for spectrum sensing, according to an exemplary implementation of the present invention.
[0027] It should be appreciated by those skilled in the art that any
block diagrams herein represent conceptual views of illustrative methods embodying the principles of the present invention. Similarly, it will be appreciated that any flow charts, flow diagrams, and the like represent various processes which may be substantially represented in computer-readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

DETAILED DESCRIPTION
[0028] The various embodiments of the present invention describe a
method and an N-plexer based receiver architecture for spectrum sensing.
[0029] In the following description, for purpose of explanation,
specific details are set forth in order to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of systems.
[0030] However, the systems and methods are not limited to the
specific embodiments described herein. Further, structures and devices shown in the figures are illustrative of exemplary embodiments of the presently invention and are meant to avoid obscuring of the present invention.
[0031] It should be noted that the description merely illustrates the
principles of the present invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present invention. Furthermore, all examples recited herein are principally intended expressly to be only for explanatory purposes to help the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.

[0032] The detailed description set forth below is intended as a
description of exemplary designs of the present invention and is not intended to represent the only designs in which the present invention can be practiced. The term “exemplary” issued herein to mean serving as an example, instance, or illustration. Any design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other designs. The detailed description includes specific details for the purpose of providing a thorough understanding of the exemplary designs of the present invention. It will be apparent to those skilled in the art that the exemplary designs described herein may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the novelty of the exemplary designs presented herein.
[0033] In one of the embodiments, the present invention discloses
an RF multiplexing technique. This novel analytical RF multiplexing technique is introduced, and a corresponding circuit is implemented. For the broadband jamming purpose, instead of opting for a broadband configuration, an N plexer based architecture is implemented.
[0034] An advantage over the power divided configuration
frequently used in such a module is that the total power can be utilized all at once instead of losing the corresponding power in the divider circuit. Such a structure is highly reconfigurable in the sense that with the advent of new spectrum over the advancement of wireless standards, minimal modifications have to be done in the circuit to accommodate the new frequency bands. The implemented circuit works for LTE bands 1,3,5,40,41 with noise figure ≤ 2.6 dB and return loss ≤ -10 dB for the entire band of operation.

[0035] In another embodiment, the present invention discloses an
N-plexer based receiver architecture that can work as a spectrum sensing instrument for LTE jammer application which works simultaneously in multiple bands having low N.F, low insertion loss, and low interference between multiple frequency bands. The N-plexer based receiver architecture is sufficient to fulfill all these requirements. Especially for jamming sensing purposes, the broadband receiver is required. Instead of broadband sensing, multiband sensing is done. In multiband sensing, a particular communication band is sensed, instead of the whole band that facilitate parallel receivers implementation to improve intercept time. When a new band comes into the picture for communication and if it is required to be jammed, a sensing arm can be easily attached in very less time.
[0036] In another embodiment, the present invention discloses
about multiband sensing that can be done by a broadband receiver by passing the RF signal first through a power divider and then subsequently through the bandpass filters. During this process, a loss is realized. This loss can be reduced by frequency splitting without using power divider. Technically this type of frequency splitter is termed as Diplexer, Triplexer or the N-plexer depending on the number of output ports it has where different band signals are received at a dedicated port of the receiver with low loss. In a power divider based band separator, {(10logN) dB + Filter loss} gives the insertion loss but we save almost (10 logN) dB loss by using the N-plexer. A diplexer, Triplexer, Quadplexer, etc. is a subset of N-plexer.
[0037] In another embodiment, the N-plexer comprising an RF
circuit is provided. The designed RF circuit can give an N-Band output with disjoint frequency characteristics by splitting the single broadband

low power received input RF signal or it can give a single broadband low power Transmit Signal combining the N-Band input with the disjoint frequency characteristics.
[0038] In an exemplary implementation, the present invention
describes a method for N-plexer based receiver architecture for spectrum sensing comprising steps of receiving, by a signal conditioning circuit block, a broadband radio frequency (RF signal) transmitted from a transmitter; and suppressing, by a splitter block, the received broadband RF signals into independent N-sub-band RF signals with disjoint frequency characteristics; wherein the splitting criteria of the received broadband RF signals are based on the value of required stages.
[0039] In another exemplary implementation, the present invention
describes the method steps of creating, by an SPDT (single pole double throw) switch (Block-3), high isolation between transmission and reception path, wherein the transmission and the reception path is between the transmitter and the receiver; reducing, by a low noise amplifier (LNA) (Block-5), a filter loss ;limiting, by a limiter 1 (Block-4), the receiving power signals so that the receiving power signals are not so high as to drive the LNA into saturation; and protecting, by a limiter 2 (block 6), an analog to digital converter from unwanted spikes of the signals.
[0040] In another embodiment, the present invention discloses an
N-plexer based receiver architecture. The N-plexer based architecture includes a signal conditioning circuit block configured to receive a broadband radio frequency (RF signal) transmitted from a transmitter. The N-plexer based architecture further includes a splitter block configured to split the received broadband RF signals into independent N-sub-band RF

signals with disjoint frequency characteristics. The splitting criteria of the received broadband RF signals are based on the value of the required stages.
[0041] In another embodiment, the present invention discloses a
signal conditioning circuit block. The signal conditioning circuit block comprising, an SPDT (single pole double throw) switch (Block-3) configured to create high isolation between transmission and reception path, wherein the transmission and the reception path is between the transmitter and the receiver. The signal conditioning circuit block further includes a low noise amplifier (LNA) (Block-5) configured to reduce the filter loss. The signal conditioning circuit block further includes a limiter 1 (Block-4) configured to limit the receiving power signals so that the receiving power signals are not so high as to drive the LNA into saturation. The signal conditioning circuit further includes a limiter 2 (block 6) configured to limit an analog to digital converter from unwanted spikes of the signals.
[0042] In another embodiment of the present invention, the number
of the required stages depends upon the number of the bands required for the receiver design is disclosed.
[0043] In another embodiment of the present invention, the
frequency splitter block as a Diplexer, Triplexer, or a Quadplexer may be used is described.
[0044] In one another embodiment of the present invention, the
frequency splitter block is designed by connecting a plurality of unit cells of the individual split frequency N-sub-bands sequentially is disclosed.

[0045] In one another embodiment of the present invention, the
plurality of the unit cell comprises a plurality of RF network and bandpass filters are disclosed. The bandpass filter separates the received broadband signal under consideration from the other bands of the received broadband signal with a low insertion loss and high isolation.
[0046] In another embodiment, the present invention discloses a
unit cell that can be a combination of a plurality of RF networks and a plurality of stubs.
[0047] In another embodiment of the present invention, ‘1 to N’
band splitter circuit, suitable for any specific frequency range, that may be designed for any system impedance is disclosed.
[0048] In another embodiment of the present invention, the band is
separated in four-sub bands to prevent design turn-around time is disclosed.
[0049] In an exemplary embodiment, the present invention
discloses the advantages. The most important advantage of the N-plexer is low power loss. Physically N paths are designed in the RF circuit configuration, but one path is dedicated for particular sub-band in N-plexer and that signal does not enter any of the other paths. The N-plexer based circuits make transceivers superior to duplexer and switch-based transceivers in terms of simultaneously working of transmitter and receiver at a particular instance of time. Utilizing the same advantage, a multi-band transmission and multi-band reception of RF signals is achieved.

[0050] In the prior art, a switch is used for multiplexing, so at a
time, only one band is transmitted/received, but in the present invention all desired bands work simultaneously.
[0051] In the prior art, a filter for the design and PCB is claimed but
in the present invention, band-specific filters have taken and focus on the placement of filters with proper circuits.
[0052] The prior art discloses that interfacing with the antenna for
communication, the Diplexer, the Triplexer, or the Quadplexer is used. But the present invention focuses on the Diplexer, the Triplexer, the Quadplexer, or the N-plexer design.
[0053] The prior art part focuses on design and fabrication of N
number of high isolation and high Q FBAR bandpass filters so the inventor claimed on FBAR filter design and fabrication not on the design of the N-plexer but in the present invention, any band-specific filters have been selected and design the N-plexer with the filters by proper arrangement and placement of the filter.
[0054] In the prior art the Pentaplexer system is based on a
reflection of light for their multiplexing purpose but as present invention deals with RF signal so proper impedance matching is the main criterion.
[0055] The prior art claims only on the Triplexer while the present
invention is based on N-plexer. λ/4 wavelength impedance inversion technique is used for the Triplexer design but in the present invention, T.L and stub that is used may be or may not be a λ/4 line. In the prior art, the inventor designed a filter for their design and claiming their design and PCB but in the present invention band, specific filters have taken and focus on the placement of filters with proper circuits.

[0056] Fig. 1 illustrates a basic block diagram (100) depicting an N-
plexer (Pentaplexer) chain with a signal conditioning block.
[0057] The design capability is not restricted only to a Triplexer,
Quadplexer, or a Pentaplexer. The receiver design can be extended to the N-plexer design. The N-plexer as a multiband receiver architecture is designed by using a plurality of the Diplexer, the Triplexer, or the Quadplexer.
[0058] For the N-plexer receiver architecture design the number of
the required stages has to be fixed. The number of stages depends on the number of bands required in the design. Once the number of the stages is fixed, by using the formula, the required stages are calculated. If the number of bands is N, then
Number of Stages = 1 + [log4 N] ; if N =£ 4A where A E I -, and where I is a positive integer.
Number of Stages = [log4 N] ; if N = 4A
where A e I ; and where I is a positive integer.
[ ] = greatest integer function
[0059] Here for the Pentaplexer value of N= 5 is taken. Further, the
required stages are calculated by the formula using the value of N. The required number the stages for the Pentaplexer is 2.
[0060] The N-plexer (Pentaplexer) based receiver architecture
includes the signal conditioning circuit Block-1 (102) and a frequency splitter block Block-2 (104).

[0061] The signal conditioning circuit block (102) receives a
broadband radio frequency (RF signal) transmitted from a transmitter (not shown in Fig.). The received broadband radio frequency signals are transmitted towards the frequency splitter Block 2 (104). The frequency splitter Block 2 (104) split them into an independent N-sub-band RF signals with high isolation and having disjoint frequency characteristics.
[0062] Because this is the case of Pentaplexer, so the received
broadband RF signals are split into 5 LTE independent bands with high isolation i.e. band 5, band 1, band 3, band 40, band 41. For the Pentaplexer design, a Diplexer followed by a bandpass filter of band 5 and a Quadplexer is required and is explained further in detail through Fig. 3 of the present invention.
[0063] Fig. 2 illustrates a block diagram (200) depicting a receiver
chain, according to an exemplary implementation of the present invention.
[0064] The block diagram (200) is a descriptive part of the Block 1,
the signal conditioning circuit (102). Since, Fig.2 is the single conditioning circuit (102), the basic receiver criterion is taken care of such as LOW noise figure, RF protection circuits, and isolation of Rx from Tx. The signal conditioning circuit (102) comprises four blocks namely Block-3, Block-4, Block-5, and Block-6.
[0065] The Block-3 contains an SPDT (single pole double throw)
switch (202). The SPDT (single pole double throw) switch (2020 is configured to create high isolation between transmission and reception path. The transmission and the reception path is between the transmitter and the N-plexer based receiver.

[0066] Further, Block-5 contains a low noise amplifier (LNA) (204).
The low noise amplifier (LNA) (204) is configured to reduce the filter loss.
[0067] Further, Block 4 contains a limiter 1 (206). The limiter 1 (206)
is configured to limit the receiving power signals so that the receiving power signals are not so high as to drive the LNA (204) into saturation. LNA (204) helps to reduce overall N.F., it compensates filter loss.
[0068] Further, Block 6 contains a Limiter 2 (208). The broadband
spectrum is monitored on the screen through an analog to digital converter. The limiter 2 (208) is configured to limit an analog to digital converter from unwanted spikes of the signals.
[0069] Fig. 3 illustrates a schematic diagram (300) depicting an N-
plexer (Pentaplexer) describing the Quadplexer and the Diplexer network, according to an exemplary implementation of the present invention. For the Pentaplexer design, the Diplexer followed by the bandpass filter of Band 5 and the Quadplexer is needed. The N-plexer is designed to fulfill the multiband sensing, multichannel carrier aggregation like other multiband applications. The N-plexer is a bi-directional circuit that splits the broadband RF signals that may be sensed by an antenna into N-band RF signals. Due to Bi-directional property, the present invention is also used for carrier aggregation and signal combining circuit (104) at the PA input.
[0070] A Network-A of the present invention is the Diplexer circuit
(302) and Network-B is the Quadplexer circuit (104). The Diplexer circuit (302) receives the RF broadband signals as RF IN signals. The received broadband signals are split. One of the split broadband signals i.e. band 5 is the output of the bandpass filter. Subsequently, the other split band

signals are sent towards the Network B i.e. the Quadplexer circuit (104). The received signals are further subdivided into band 1, band 3, band 40, and band 41.
[0071] Fig. 4 illustrates a schematic diagram (400) depicting a stage
calculation and N-plexer splitting criterion, according to an exemplary implementation of the present invention. Fig. 4 describes the N-plexer stages and basic architecture.
[0072] By using the formula, the minimum number of the stages
required for a given number of the bands is calculated:
Number of Stages = 1 + [log4 N] ; if N =£ 4A where A E I ; and where I is a positive integer.
Number of Stages - [log4 N] ; if N — 4A
where A 6 I ; and where I is a positive integer.
[] = greatest integer function Below are some examples for calculating the number of stages:
1) Suppose N=5 7) Suppose N=64=43
Stages = 1 + [log4 JV] Stages = [log* N]
= 1 + [1.16] = [log464]
=_?_ =3
2) Suppose N=3 fy Suppose N=S5
Stages = 1 +■ [log4 N] Stages = 1 + [log4 N]
= 1 + [0.79] = 1+ [3.012]
=_J =_4
3) Suppose N=4 =4' 9) Suppose N=12S
Stages = [log, N] Stages = 1 + [log,, JV]
= [log44] = 1+[3.012]
=J = 4
4) Suppose N =29 10) Suppose N=12B
Stages = 14- [log4 JV] Stages = 1 + [log4 JV]
= 1+[2.428] = 1+[3.5]
=_J =_A
5) Suppose N =$3 11) Suppose N=255
Stages = 1 + [log4 JV] Stages = 1 + [log, JV]
= 1 +[2.961 = 1+[3S9]
= 3 =4
B) Suppose N=129 12) Suppose N=256=4"
Stages = 14- [logiW] Suges = [log4 N]
= 1 + [3.511 =[log42E6]
-_4 1 =_*

[0073] The design capability need not be restricted to only Triplexer,
Quadplexer or Pentaplexer. It can be extended to an N-Plexer design. An N-plexer is an innovative part that makes this design novel. For Pentaplexer design, the diplexer followed by a band pass filter of band 5 and a Quadplexer is required. An N-plexer can be designed to fulfill multiband sensing, multi-channel carrier aggregation like other multi-band applications. N-plexer is a bi-directional circuit that splits a broadband RF signal that may be sensed by the antenna into N-band RF signals. Due to Bi¬directional property, the invention can be also used for carrier aggregation and signal combining circuit at the PA input.
[0074] Fig. 2 illustrates a block diagram (011) depicting a receiver
chain. The received broadband RF signals are passed through the signal conditioning circuit (102). The received broadband is split into four different bands A1 (404), A2 (406), A3 (408), and A4 (410) respectively by the frequency splitter block (104). The different stages i.e. stage-A, stage-B, stage-C, and stage-Kth.
From the initial stage to the end-stage every band is split into four bands by the Quadplexer. Splitting of the bands makes the invention superior to prior inventions. For example, a band is to be incorporated in exiting N-plexer design. (N+1)-plexer design can be done by redesigning the N-plexer with the least modification. This can be understood by following the example of frequency splitting by the diplexer circuit of the present invention using Fig. 5.
[0075] Fig. 5 illustrates a block diagram (500) depicting a Band
splitting criterion. In Fig. 5, the Pentaplexer (N=5) based receiver architecture is taken. The diplexer circuit (104) splits the received broadband RF signals into band Bx and By. Subsequently, a circuit A (502)

splits the received band signals Bx into sub-bands signal Bx1, Bx2, Bx3,
Bx4. Also, from a Circuit B (502), By1 is a bandpass filtered output.
Suppose in future By2 band also comes into interest, that happens to be a subset of By. Due to this additional band, the receiver circuit needs to be redesigned, that is the Circuit B has to be changed.
[0076] Fig. 6 illustrates a schematic diagram (600) depicting a unit
cell of N-plexer.
[0077] In Fig. 6, the Quadplexer used in the N-plexer is made from
the unit cells. The unit cell is designed using the band-specific filter as shown in Fig 6. The unit cell consists of section-1(602) and section-2 (604). The section (602) is the RF network and the section-2 (604) is the bandpass filter which separates the band under consideration from other bands with low insertion loss and high isolation.
[0078] The Unit Cell designed in the present invention, which in
turn comprises the RF network(602) and the suitable bandpass filter meeting the band definition of output branch (604), and also which has low insertion loss in a particular band and high rejection in other bands.
[0079] Fig. 7 illustrates a schematic diagram (700) depicting an RF
network of the unit cell.
[0080] Fig. 7, shows the RF network part of the unit cell. The RF
network of the unit cell consists of section-3 (702), section-4 (704), and section-5 (706). The section-3 (702) and section-4 (704) are transmission lines, and section-5 (706) is a stub. Section-3 (702), section-4 (704), and section-5 (706) make sure that specific band pertaining to the unit cell passes on and at the same time, other bands are reflected back simultaneously.

[0081] Fig. 8 illustrates a block diagram (800) depicting a connection
of unit cell to design N-plexer.
[0082] In Fig. 8, altogether N-unit cells are to be made for realizing
the N-plexer, where the N-unit cells for all required bands are used for the construction of the Quadplexes, the Triplexers, the Diplexers, and the bandpass filters. For making one Quadplexer the Unit cells are to be combined sequentially as shown in Fig. 8.
[0083] The block (800) of the present invention consists of different
unit cells namely unit cell 802, unit cell (804), and unit cell 806. These unit cell 802, unit cell 804, the unit cell 806, and the unit cell 808 are used in the construction of the Quadplexer circuit. The Quadplexer circuit of the N-plexer based receiver architecture is designed by connecting the unit cells of individual frequency bands sequentially.
[0084] Fig. 9 illustrates a block diagram (900) depicting an N-plexer
for multi-band receiving purpose.
[0085] In Fig. 9, the N-plexer based receiver architecture comprising
Block-A (RF circuit) (902) is disclosed. The N-plexer comprising the RF circuit (902) wherein the so designed RF circuit (902, can give an N-Band output with the disjoint frequency characteristics by splitting the single broadband low power received input RF signals or can give a single broadband low power Transmit Signals combining an N-Band input with disjoint frequency characteristics.
[0086] Fig. 10 illustrates a block diagram (1000) depicting an N-
plexer for transmitting the combined multi-band signal. The split N-band disjoint signal is further transmitted towards the transmitter (not shown in Fig.) through Block-B.

[0087] Fig. 11 illustrates a block diagram (1100) for the process
involved in designing an N-plexer, according to an exemplary implementation of the present invention.
[0088] In Fig. 11, as per the requirement the number of split bands
required for the system is designated as N. From N, the number of stages is calculated using the given following equations.
For example, if the number of bands is N, then,
�������������� = � + [�����]; if � ≠ �� where � ∈ � ; ���������������������������. ������������� � = [�����]; if � = �� where � ∈ � ; ��� ����� � �� � �������� ������� .
[ ] = greatest integer function .
[0089] As per the band specifications of each output bandpass
filters are either selected or designed. The main parameter to be kept in mind is the pass-band insertion loss. The stopband rejection is not very specific since the unit cell design takes care of it. With the selected band pass filters the unit cell is designed keeping in mind the stopband requirements of its other 3 companion unit cells. This is an iterative process which is a core RF design activity. Once the unit cell components are finalized the 4-unit cells are joined using transmission lines of the receiver characteristic impedance. The same procedure is repeated for any number of 4-unit cell branches that are present in the receiver. The complete splitting or combining network is finally completed using transmission lines of receiver impedance.

[0090] Fig. 12 illustrates a method for an N-plexer based receiver
architecture for spectrum sensing, according to an exemplary implementation of the present invention.
[0091] Referring now to Fig. 12 which illustrates a flowchart (1200)
the method for the N-plexer based receiver architecture for spectrum sensing, according to an exemplary implementation of the present invention. The flow chart (1200) of Fig. 12 is explained below with reference to Fig.1 as described above.
[0092] At step 1202, receiving, by a signal conditioning circuit block
(102), a broadband radio frequency (RF signal) signals transmitted from a transmitter.
[0093] At step 1204, splitting, by a frequency splitter block (104) the
received broadband RF signals into independent N-sub-band RF signals with disjoint frequency characteristics, and
[0094] At step 1206, the splitting criteria of the received broadband
RF signals are based on the value of required stages is calculated.
[0095] The foregoing description of the invention has been set
merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the invention.

We Claim:
1. A method for N-plexer based receiver architecture for spectrum sensing comprising:
receiving, by a signal conditioning circuit block (102), a broadband radio frequency (RF signal) signals transmitted from a transmitter; and
splitting, by a frequency splitter block (104) the received broadband RF signals into independent N-sub-band RF signals with disjoint frequency characteristics;
wherein the splitting criteria of the received broadband RF signals are based on the value of required stages. 2. The method as claimed in claim 1 further comprising:
creating, by an SPDT (single pole double throw) switch (Block-3) (202), high isolation between transmission and reception path, wherein the transmission and the reception path is between the transmitter and the N-plexer based receiver;
reducing, by a low noise amplifier (LNA) (Block-5) (206), a filter loss;
limiting, by a limiter 1 (Block-4) (204), the receiving RF power signals so that the receiving RF power signals are not so high as to drive the LNA (206) into saturation; and
protecting, by a limiter 2 (Block 6) (208), an analog to digital converter from unwanted spikes of the signals.

3. An N-plexer based receiver architecture for spectrum sensing
comprising:
a signal conditioning circuit block (102) configured to receive a broadband radio frequency (RF signal) transmitted from a transmitter; and
a frequency splitter block (104) configured to split the received broadband RF signals into independent N-sub-band RF signals with disjoint frequency characteristics;
wherein the splitting criteria of the received broadband RF signals are based on the value of required stages.
4. The N-plexer based receiver architecture as claimed in claim 1,
wherein the signal conditioning circuit block (102) comprising:
an SPDT (single pole double throw) switch (Block-3) (202) configured to create high isolation between transmission and reception path, wherein the transmission and the reception path is between the transmitter and the N-plexer based receiver;
a low noise amplifier (LNA) (Block-5) (206) configured to reduce the filter loss;
a limiter 1 (Block-4) (204) configured to limit the receiving RF power signals so that the receiving RF power signals are not so high as to drive the LNA (206) into saturation; and

a limiter 2 (block 6) (208) configured to limit an analog to digital converter from unwanted spikes of the signals.
5. The N-plexer based receiver architecture as claimed in claim 3, wherein the number of the required stages depends upon the number of the bands required for the N-plexer based architecture receiver design.
6. The N-plexer based receiver architecture as claimed in claim 3, wherein the N-plexer based receiver architecture is designed by using a plurality of Diplexer (104), Triplexer, or a Quadplexer.
7. The N-plexer based receiver architecture as claimed in claim 1, wherein the frequency splitter block (104) is designed by connecting a plurality of unit cells of the individual split frequency N-sub-bands sequentially.
8. The N-plexer based receiver architecture as claimed in claim 7, wherein the plurality of the unit cell comprises a plurality of a RF networks and bandpass filters, wherein the bandpass filter separates the received broadband signals under consideration from the other bands of the received broadband signals with a low insertion loss and high isolation.
9. The N-plexer based receiver architecture as claimed in claim 8, wherein the plurality of the RF networks consists of a plurality of transmission lines and a plurality of stubs.

10. The N-plexer based receiver architecture as claimed in claim 3, wherein the N-plexer receiver may be designed for any specific range for any system impedance. Dated this 27th day of March, 2020