Claims:1. A radio frequency selection matrix (100) comprising:
a stack comprising a housing (102) having a width and adapted to hold one or more printed circuit boards, the one or more printed circuit boards comprises a RF module (104), said RF module comprising:
a plurality of input channels (110-1, 110-2); and
a plurality of output channels (112-1 to 112-4), wherein the incoming frequency signals of a predefined range received by the plurality of input channels and are power divided and routed to the plurality of output channels using one or more non-reflective single pole double throw switches (208-1 to 208-3, 222).
2. The radio frequency selection matrix as claimed in claim 1, wherein the one or more non-reflective single pole double throw switches facilitate very high isolation among the plurality of input channels (110-1, 110-2) and the plurality of output channels (112-1 to 112-4).
3. The radio frequency selection matrix as claimed in claim 1, wherein the plurality of input channels (110-1, 110-2) comprises low noise amplifiers (204, 218) at front end, which facilitate low noise figure, and RF chain of the RF module comprises signal selection devices (202, 214, 216) providing very low spurious at the plurality of output channels over wide frequency band.
4. The radio frequency selection matrix as claimed in claim 1, wherein the one or more PCBs comprises power supply module (400), digital module (500) and BIT module (300).
5. The radio frequency selection matrix as claimed in claim 1, wherein the plurality of input channels comprises a first input channel (110-1) and a second input channel (110-2), wherein the first input channel, the BIT module, the power supply module, the digital module and AC-DC converter located on bottom side of the housing, wherein the second input channel and the plurality of output channels located on top side of the housing.
6. The radio frequency selection matrix as claimed in claim 5, wherein the BIT module configured to generate frequency signals, wherein the BIT module comprises a programmable frequency generating device (308) that generates frequency signals from VHF to C-band using integrated stable reference.
7. The radio frequency selection matrix as claimed in claim 5, wherein the digital module (500) comprises a programming device (510) that interprets high speed serial interface signals and generates required digital controls.
8. The radio frequency selection matrix as claimed in claim 5, wherein the power supply module (400) comprises one or more ultra-low noise linear regulators (404-1 to 404-3) to generate DC voltages for the BIT module, the RF module and the digital module respectively, wherein low equivalent series resistance (ESR) capacitances are employed at the DC regulated output to effect spurious rejection for digital clock frequencies used for programming device and harmonics.
9. The radio frequency selection matrix as claimed in claim 1, wherein the RF signals of predefined range and BIT signals are routed to the top side from the bottom side of the one or more PCBs through vertical microstrip-coax-microstrip transition (114) facilitating compact integration.
10. The radio frequency selection matrix as claimed in claim 1, wherein the power supply signals and digital control signals are routed to the top side from the bottom side of the one or more PCBs using blind mated, spring loaded compression-based connector (116).
, Description:TECHNICAL FIELD
[0001] The present disclosure relates, in general, to switching matrix circuits, and more specifically, relates to a wideband multichannel radio frequency selection matrix.

BACKGROUND
[0002] Currently, multiple antenna systems are a very common approach used in a number of different applications like electronic warfare (EW) front end receivers, monitoring and analysis receivers. The system may be configured with multiple antennas operating in multiple frequency bands over a wide frequency range. Hence in such a system, it is desirable to switch to different radio channels, which comprises broadband power dividers and high isolation switches to avoid leakage among various input/output paths.
[0003] An existing scalable NxM switching matrix architecture is characterized by a readily calculable number of crossover locations and comprises one or more single-pole, N throw (SPNT) switches and, for each such switch, an N state impedance converter/amplitude compensation network. Another existing system fabricates a broadband switching matrix box with the low-noise figure, flat gain characteristics, and reliability by applying the chip-and-wire process using a bare-type MMIC device. To compensate for the mismatch among many components, the limiter, switch, amplifier, and power divider, which are suitable for sub-band frequency characteristics, are designed and applied to the matrix box. Yet another existing power combiner circuit for RF signals includes a multi-path network for conveying a plurality of RF signals over a selected path or paths, to a common node. However, these existing approaches are limited in application and frequency and cannot work over very large bandwidths for a number of reasons.
[0004] Therefore, it is desired to develop a simple and cost-effective means that operates over a broad frequency spectrum.

OBJECTS OF THE PRESENT DISCLOSURE
[0005] An object of the present disclosure relates, in general, to switching circuits, and more specifically, relates to a wideband multichannel radio frequency selection matrix.
[0006] Another object of the present disclosure is to provide a device that operates over a broad frequency spectrum from VHF band to C band.
[0007] Another object of the present disclosure is to provide a lightweight and compact device including multiple wideband vertical RF transitions and a blind mated connector for routing various power supply and control signals.
[0008] Another object of the present disclosure is to provide a device that provides extremely low spurious at outputs over a wide frequency band.
[0009] Another object of the present disclosure is to provide a device that achieves a low noise figure.
[0010] Another object of the present disclosure is to provide a device that enables very high isolation among the input channels and output channels over the entire frequency band.
[0011] Another object of the present disclosure is to provide a device that provides flat gain response over frequency and temperature.
[0012] Another object of the present disclosure is to provide a device that provides integrated fast switching built-in test (BIT) capability.
[0013] Another object of the present disclosure is to provide a device that is capable to function at 25000 feet of altitude and under continuous rain like environmental conditions
[0014] Yet another object of the present disclosure is to provide a device with low power consumption.

SUMMARY
[0015] The present disclosure relates, in general, to switching circuits, and more specifically, relates to a wideband multichannel radio frequency selection matrix.
[0016] In an aspect, the present disclosure relates to a device includes a stack comprising a housing having a width and adapted to hold one or more printed circuit boards, the one or more printed circuit boards comprises a RF module, the RF module comprising a plurality of input channels, and a plurality of output channels, wherein the incoming frequency signals of a predefined range received by the plurality of input channels and are power divided and routed to the plurality of output channels using one or more non-reflective single pole double throw switches.
[0017] According to an embodiment, the one or more non-reflective single pole double throw switches facilitate very high isolation among the plurality of input channels and the plurality of output channels.
[0018] According to an embodiment, the plurality of input channels comprises low noise amplifiers at front end which facilitate low noise figure, and RF chains of the RF module comprises of signal selection devices providing very low spurious at the plurality of output channels over wide frequency band.
[0019] According to an embodiment, the one or more PCBs comprises of power supply module, digital module and BIT module.
[0020] According to an embodiment, the plurality of input channels comprises a first RF input channel and a second RF input channel, wherein the first RF input channel, the BIT module, the power supply module, the digital module and AC-DC converter 108 located on bottom side of the housing, wherein the second RF input channel and the plurality of output channels located on top side of the housing.
[0021] According to an embodiment, the BIT module configured to generate frequency signals, wherein the BIT module comprises a programmable frequency generating device that generates frequency signals from VHF to C-band using integrated stable reference.
[0022] According to an embodiment, the digital module comprises a programming device that interprets high speed serial interface signals and generates required digital control signals.
[0023] According to an embodiment, the power supply module comprises AC-DC converter, one or more ultra-low noise linear regulators to generate DC voltages for the BIT module, the RF module and the digital module respectively, wherein low equivalent series resistance (ESR) capacitances are employed at the DC regulated output to effect spurious rejection for digital clock frequencies used for programming device and harmonics.
[0024] According to an embodiment, the RF signals of predefined range and BIT signals are routed to the top side from the bottom side of the PCBs through vertical microstrip-coax-microstrip transition facilitating compact integration.
[0025] According to an embodiment, the power supply signals and digital control signals are routed to the top side from the bottom side of the PCBs using blind mated, spring-loaded compression-based connector.
[0026] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The following drawings form part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.
[0028] FIG. 1A illustrates an exemplary view of wideband multichannel radio frequency selection matrix (WMRSM), in accordance with an embodiment of the present disclosure.
[0029] FIG. 1B illustrates cross-sectional view of RF transitions, in accordance with an embodiment of the present disclosure.
[0030] FIG. 1C illustrates cross-sectional view of power supply and digital control transitions, in accordance with an embodiment of the present disclosure.
[0031] FIG. 2A illustrates schematic view of second RF input channel of radio frequency module, in accordance with an embodiment of the present disclosure.
[0032] FIG. 2B illustrates schematic view of first RF channel of radio frequency module, in accordance with an embodiment of the present disclosure.
[0033] FIG. 3 illustrates a schematic view of the BIT module, in accordance with an embodiment of the present disclosure.
[0034] FIG. 4 illustrates a schematic view of the power supply module, in accordance with an embodiment of the present disclosure.
[0035] FIG. 5 illustrates a schematic view of the digital module, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0036] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0037] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0038] The present disclosure relates, in general, to switching circuits, and more specifically, relates to a wideband multichannel radio frequency selection matrix. The device of the present disclosure enables to overcome the limitations of the prior art by providing wideband multichannel radio frequency selection matrix (WMRSM), which is an ultra-wideband front end RF selection unit, for processing multi-octave (> 7 octaves) frequency signals, ranging from VHF to C band. The compact integration and lightweight design of the WMRSM can be achieved using vertical coax based microstrip-coax-microstrip transitions and board-to-board connectors. The WMRSM provides proper channelling in the PCBs and mechanical housing to ensure high isolation among input and output channels.
[0039] The proposed device achieves very low spurious in the output signal. WMRSM accepts high-speed serial interface commands for digital controls required for RF switches and frequency selection. The present disclosure can be described in enabling detail in the following examples, which may represent more than one embodiment of the present disclosure. The description of terms and features related to the present disclosure shall be clear from the embodiments that are illustrated and described; however, the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents of the embodiments are possible within the scope of the present disclosure. Additionally, the invention can include other embodiments that are within the scope of the claims but are not described in detail with respect to the following description.
[0040] FIG. 1A illustrates an exemplary view of wideband multichannel radio frequency selection matrix (WMRSM), in accordance with an embodiment of the present disclosure.
[0041] Referring to FIG. 1A, the wideband multichannel radio frequency (RF) selection matrix (WMRSM) 100 (also referred to as device 100 herein) is an ultra-wideband front-end RF selection unit, which finds application in communication systems and front-end receivers. The device 100 can be configured for processing multi-octave e.g., greater than 7 octaves frequency signals, ranging from very high frequency (VHF) to C band. The device 100 can include three sub-modules, where the first module can include radio frequency (RF) module 104 shown in FIG. 2A, a second module 106 can include power supply module 400, digital module 500, built-in test (BIT) generation module 300 shown in FIG. 3 to FIG. 5 respectively and third module can include AC-DC conversion module 108. The device 100 can be employed in various communication systems, front end receivers, electronic support systems, laboratory tests and evaluation purposes.
[0042] In an embodiment, the device 100 includes a stack that can include the housing 102 having a width and adapted to hold the printed circuit boards, the printed circuit boards can include the RF module 104, BIT module 300 shown in FIG. 3, power supply module 400 shown in FIG. 4, digital module 500 shown in FIG. 5 respectively. The RF module 104 can include one or more input channels (110-1, 110-2) and one or more output channels (112-1 to 112-4). In an exemplary embodiment, one or more input channels (110-1, 110-2) can be dual RF input channels and one or more output channels (112-1 to 112-4) can be four output channels. The dual RF input channel can include a first RF input channel 110-1 and a second RF input channel 110-2. The second RF input channel 110-2 and one or more RF output channels (112-1 to 112-4) are located on one side of the RF module 104 i.e., top side of housing and the first RF input channel 110-1, BIT module 300, power supply module 400, digital module 500 and AC-DC converter 108 located on the other side of the RF module 104 i.e., bottom side of housing.
[0043] In another exemplary embodiment, the device 100 can be realized as the stack of two PCBs on either side of the mechanical housing 102, where the top side of housing 102 can include RF module 104 operating from VHF to C-band and provides RF signals as outputs to the succeeding stages. The bottom side of the housing 102 can include an RF module 104 operating up to VHF band, BIT generation module 300, power supply distribution module 400, digital module 500 and AC-DC converter 108. The PCBs are hybrid multilayer stack with minimized RF criss-cross.
[0044] The incoming signals of a predefined range e.g., VHF to C-band is power divided and routed to multi-channel output paths/channels (112-1 to 112-4) using one or more single pole double throw switches. High isolation is achieved among the various input/output channels by using non-reflective switches in each of the paths. It has integrated programmable built-in test module 300 and power supply module 400 with integrated electromagnetic interference (EMI) filtering. The module is stacked up of multilayer hybrid PCBs on either side of the chassis/ housing with minimum RF criss-cross, thereby providing minimum interference among adjacent channels.
[0045] The BIT module 300 indicated in FIG. 3 generates the required frequencies from VHF to C-band using frequency generating device 308. The RF signals up to VHF band and BIT signals are routed to the top side via vertical microstrip-coax-microstrip transition 114. The AC-DC conversion module 108 receives the AC power supply and converts it to DC. The power supply module 400 can include ultra-low noise regulators (404-1 to 404-3) to achieve low output spurious performance. The device 100 accepts high-speed serial interface commands for digital controls required for RF switches and frequency selection in BIT module 300. The digital controls and power supply for the top side are routed from the bottom side via blind mated, spring-loaded compression-based connector 116. The vertical microstrip-coax-microstrip transition 114 and use of board-to-board connector 116 resulted in compact sized and light weighted module design.
[0046] The device 100 is preceded by multiple antennas of the system. RF chain of the RF module 104 can include low noise amplifiers (204, 218), low pass filters (202, 214, 216), power dividers (206, 220) and one or more non-reflective switches (208-1 to 208-3, 222) shown in FIG. 2A and FIG. 2B respectively to route various inputs channels to various outputs channels, where channelling is performed in the PCBs and mechanical housing to ensure high isolation among input and the output channels. In an exemplary embodiment, the one or more non-reflective switches can be single pole double throw (SPDT) switches.
[0047] FIG. 1B illustrates cross-sectional view of RF transitions, in accordance with an embodiment of the present disclosure. The first RF input channel, BIT signals generated, power supply and digital controls are required to be routed from the bottom side of the RF module 104 to the top side of the RF module using vertical microstrip-coax-microstrip transition 114 as shown in FIG. 1B. The device can include vertical microstrip-coax-microstrip transition 114 at multiple locations, which resulted in compact integration of the device 100.
[0048] FIG. 1C illustrates cross-sectional view of power supply and digital control transitions, in accordance with an embodiment of the present disclosure. The device 100 can include blind mated spring compression-based board-to-board connector 116 configured for routing multiple digital controls and multiple supply lines, which resulted in easy assembly and compact integration of the device 100.
[0049] FIG. 2A illustrates schematic view of second RF input channel 110-2 of radio frequency module, in accordance with an embodiment of the present disclosure. The second RF input channel 110-2 of the RF module 104 receives input in the frequency range of ultra-high frequency (UHF) to C-band. The second RF input channel 110-2 of the RF module 104 can include low pass filter 202, low noise amplifier 204, 4-way power divider 206, one or more single pole double throw switches (208-1, 208-2, 208-3), amplifier 210, amplitude response controlling devices 212 and low pass filter 214. The one or more single pole double throw switches can include a first single pole double throw switch 208-1, second single pole double throw switch 208-2 and third single pole double throw switch 208-3. The RF chains can include signal selection devices (202, 214, 216) (also referred to as low pass filters, herein) providing very low spurious at output channels over the wide frequency band.
[0050] The incoming signals is received by the second RF input channel 110-2, that are power divided and routed to multi-channel output paths (112-1 to 112-4) using one or more single pole double throw switches (208-1 to 208-3). The low pass filter 202 is configured to reject out of band frequencies, followed by the low noise amplifier 204. The output of low noise amplifier 204 is received by the 4-way power divider 206, where the power divider 206 distributes the input signal equally between its outputs. Each output of the power divider 206 is connected to an input of the first single pole double throw switch 208-1.
[0051] The first single pole double throw switch 208-1 with one port terminated to provide high isolation. The second single pole double throw switch 208-2 is configured to route RF output to either first input channel 110-1 or second input channel 110-2. The third single pole double throw switch 208-3 is configured to route RF output to either RF input channels or BIT paths. The amplifier 210 provides the required gain. Similar RF chain is replicated for other radio frequency output channels.
[0052] FIG. 2B illustrates schematic view of first RF channel 110-1 of radio frequency module, in accordance with an embodiment of the present disclosure. The first RF channel 110-1 receives input in the frequency range of VHF band. The first RF channel 110-1 of the RF module can include low pass filter 216, low noise amplifier 218, 4-way power divider 220, single pole double throw switch 222. The first RF channel 110-1 receives input in the frequency range of VHF band. The low pass filter 216, whose output is connected to the low noise amplifier 218 configured to reject out of band frequencies. The output of low noise amplifier 218 is received by the 4-way power divider 220.
[0053] In an exemplary embodiment, the amplifiers used are wideband amplifiers with very low noise figure, low power consumption, excellent gain flatness over the entire frequency band and less sensitive to temperature variations. In an embodiment, the 4-way power divider 220, configured to power divide the incoming signals with moderate isolation and routed to multi-channel output paths using single pole double throw switch 222. Each output path is connected to the single pole double throw switch 222 with one port terminated to provide high isolation. The output of single pole double throw switch 222 is connected to the second single pole double throw switch 208-2 in the RF module 104. A similar chain is replicated for other radio frequency output channels. Proper selection of RF devices especially RF amplifiers with a very good temperature response and proper use of amplitude response controlling devices 212 aided in flat gain response over frequency and temperature.
[0054] FIG. 3 illustrates a schematic view of the BIT module 300, in accordance with an embodiment of the present disclosure. The BIT module 300 and its distribution to four radio frequency output channels is shown in FIG 3. The BIT module 300 can include reference source 302, low pass filter 304, high pass filter 306, programmable frequency generating device 308, fixed attenuator 310, 4-way power divider 312 and single pole double throw switch 314. The BIT module 300 is configured to generate frequency signals, the BIT module can include programmable frequency generating device 308 that generates frequency signals from VHF to C-band using integrated stable reference.
[0055] The inbuilt frequency source 302 is configured to generate a reference signal for programmable frequency generating device 308. The programmable frequency generating device 308 is programmed to generate the frequencies from VHF to C-band based on the received commands. The 4-way power divider 312, whose each output is connected to single pole double throw switch 314 with one port terminated. The output of the single pole double throw switch 314 is connected to the third single pole double throw switch 208-3 in RF module 104 via vertical microstrip-coax-microstrip transition 114 as shown in FIG. 1B. The similar chain is replicated for other radio frequency output channels.
[0056] FIG. 4 illustrates a schematic view of the power supply module, in accordance with an embodiment of the present disclosure.
[0057] The power supply module 400 can include one or more ultra-low noise linear regulators (404-1 to 404-3) to generate DC voltages for BIT module 300 (also interchangeably referred to as BIT section), RF module 104 (also interchangeably referred to as RF device) and digital module 500 (also interchangeably referred to as digital devices) respectively, wherein low ESR capacitances are employed at the DC regulated output to effect low spurious outputs over the wide frequency band. The power supply module 400 can include hermetic sealed connector 402, AC-DC converter 108 and ultra-low noise linear regulators (404-1 to 404-3). The AC-DC converter 108 provides DC output, where the DC output is EMI filtered appropriately and then given to ultra-low noise linear regulators (404-1 to 404-3). The ultra-low noise linear regulators (404-1 to 404-3) generate DC voltages for the BIT module 300, RF amplifiers and switches and digital circuitry respectively.
[0058] FIG. 5 illustrates a schematic view of the digital module, in accordance with an embodiment of the present disclosure. The digital controls module 500 can include connector 502, twisted pair network cable 504, transformer 506, physical layer transceiver 508, programming device 510, serial bus connector 512 and serial to binary converter 514.
[0059] The digital module 500 can include the programming device 510 that interprets high-speed serial interface signals and generates required digital controls. The RF module of WMRSM routes multiple input channels to multiple output channels and also BIT signal to multiple output channels. It receives digital controls via a high-speed serial interface, where the hermetic sealed connector 502 operates as a serial interface. In an exemplary embodiment, the hermetic sealed connector 502 can be an RJ45 connector. In another exemplary embodiment, the transformer 506 can be RJ45 transformer which aids in EMI protection.
[0060] The physical layer transceiver 508 takes in commands and generates programming lines for programming device 510 which gets its digital clock from an inbuilt stable reference source. In an exemplary embodiment, the physical layer transceiver 508 can be a LAN configuration device. The serial bus connector 512 is connected to serial to binary converter 514. This facilitates programming the programming device 510 via the serial bus interface. In an exemplary embodiment, the serial bus connector 512 can be a universal serial bus (USB) connector. In another exemplary embodiment, the serial to binary converter 514 can be USB to Universal asynchronous receiver-transmitter (UART).
[0061] The embodiments of the present disclosure described above provide several advantages. The device 100 is capable of processing multi-octave (> 7 octaves) frequency signals, ranging from VHF to C band. Compact integration and light-weight design can be achieved using vertical coax based microstrip-coax-microstrip transitions 114 for routing RF signals. The device 100 can be provided with integrated fast switching built-in test (BIT) capability. Very high isolation can be achieved among the input/output channels over the entire frequency band. Very low spurious at outputs over a wide frequency band is achieved using ultra-low noise linear regulators. The RF input channels have low noise amplifiers at the front end which aids in achieving a low noise figure. The device 100 enables flat gain response over frequency and temperature and capability to be functional at 25000 feet of altitude and under continuous rain like environmental conditions. The device 100 is capable to route any input channel to any output channel with quick change over time. The low power consuming devices used for RF and digital modules, thereby resulting in overall very low power consumption. Integrated high-speed serial communication based digital control distribution can be achieved.
[0062] Multilayer composite printed circuit boards consisting of RF, power supply and digital signals thereby easing assembly and integration. The vertical coax-based RF transitions 114 can be employed for routing BIT and RF signals to RF output paths, resulting in compact integration. The power supply and control signals are routed to RF modules using blind mated, spring loaded compression-based connector 116, resulting in compact integration. The channelling can be provided in the chassis for RF and BIT modules for achieving high isolation among input/output channels. Low ESR capacitances at the DC regulated output enhanced spurious rejection for the digital clock frequencies used for programmable devices and its harmonics.
[0063] It will be apparent to those skilled in the art that the device 100 of the disclosure may be provided using some or all of the mentioned features and components without departing from the scope of the present disclosure. While various embodiments of the present disclosure have been illustrated and described herein, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the disclosure, as described in the claims.

ADVANTAGES OF THE PRESENT DISCLOSURE
[0064] The present disclosure provides a device that operates over a broad frequency spectrum from VHF band to C band.
[0065] The present disclosure provides a lightweight and compact device including multiple wideband vertical RF transitions and a blind mated, spring-loaded compression-based connector for routing various power supply and control signals.
[0066] The present disclosure provides a device that provides extremely low spurious at outputs over the wide frequency band.
[0067] The present disclosure provides a device that achieves a low noise figure.
[0068] The present disclosure provides a device that enables high isolation among the input channels and output channels over the entire frequency band.
[0069] The present disclosure provides a device that provides flat gain response over frequency and temperature
[0070] The present disclosure provides a device that provides integrated fast switching built-in test (BIT) capability.
[0071] The present disclosure provides a device that is capable to function at 25000 feet of altitude and under continuous rain like environmental conditions
[0072] The present disclosure provides a device with low power consumption.