Omnidirectional ground-air digital phased array communication system

Abstract

The invention discloses an omni-directional ground-air digital phased array communication system, which comprises a cylindrical antenna array, a radio frequency transceiving mother board, a frequency synthesizer power supply board, a structural frame and a cooling fan, the radio frequency transceiving mother board is mounted on the structural frame, the frequency synthesizer power panel is mounted in the structural frame, data and power transmission is performed between the radio frequency transceiving mother board and the frequency synthesizer power panel, the cylindrical antenna array is conformally mounted on the structural frame, and the cooling fan is mounted at the bottom of the structural frame; the cylindrical antenna array comprises a plurality of single printed boards, each single printed board is integrated with a microstrip antenna array adopting cosecant square forming, the azimuth plane of the cylindrical antenna array can realize 360-degree scanning, and the pitching plane is fixed cosecant square forming; the radio frequency transmit-receive mother board comprises a radio frequency transmit-receive circuit, a digital transmit-receive circuit and an FPGA. According to the invention, 360-degree omnibearing radiation and electromagnetic signal receiving can be realized, a multi-beam digital signal receiving and transmitting function is realized, the integration degree is high, and miniaturization of the system can be realized.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication, specifically relating to an omnidirectional ground-to-air digital phased array communication system. Background Technology

[0002] Traditional mechanically scanned antennas suffer from high inertia and slow speed, while phased array antennas overcome these drawbacks, achieving high beam scanning speed. Phased array antennas change the shape of the radiation pattern by controlling the feed phase of the radiating elements in the array antenna to achieve beam scanning. Its feed phase is typically controlled by a computer, resulting in rapid phase changes, meaning the maximum pointing of the antenna pattern changes quickly.

[0003] Phased array beamforming technology is divided into analog and digital methods. Analog methods use radio frequency analog devices to achieve amplitude and phase adjustment of each antenna element, but the large and complex analog front end is prone to instability. Digital methods use independent ADCs and DACs to receive and generate signals for each antenna element, eliminating the need to design combiners, attenuators and phase shifters at the front end, further improving the flexibility of phased array beamforming.

[0004] The low-altitude economy is booming, and how to communicate and control UAVs that operate across all airspace and target multiple targets is attracting increasing attention. However, existing digital phased array communication systems cannot solve the following problems: 1. the problem of omnidirectional antenna radiation; 2. the problem of multi-beamforming and real-time control; 3. the problem of the complexity and large size of traditional phased array systems; 4. the problem of the high cost of traditional phased array systems. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing an omnidirectional ground-to-air digital phased array communication system that can achieve 360-degree omnidirectional radiation and reception of electromagnetic signals, has the function of transmitting and receiving multi-beam digital signals, has a high degree of integration, and can achieve system miniaturization.

[0006] To achieve the above objectives, one aspect of the present invention provides an omnidirectional ground-to-air digital phased array communication system, comprising a cylindrical antenna array, a radio frequency transceiver motherboard, a frequency synthesizer power supply board, a structural frame, and a cooling fan. The structural frame is cylindrical and located at the bottom of the system. The RF transceiver motherboard is mounted on the structural frame, and the frequency synthesizer power supply board is mounted inside the structural frame. Data and power are transmitted between the RF transceiver motherboard and the frequency synthesizer power supply board. The cylindrical antenna array is conformally mounted on the structural frame and connected to the RF transceiver motherboard. The cooling fan is mounted at the bottom of the structural frame. The cylindrical antenna array comprises multiple single printed circuit boards, each of which integrates a microstrip antenna array using cosecant square shaping. The azimuth plane of the cylindrical antenna array can achieve 360-degree scanning, while the elevation plane has fixed cosecant square shaping. The RF transceiver motherboard includes an RF transceiver circuit, a digital transceiver circuit, and an FPGA. The RF transceiver circuit is connected to a cylindrical antenna array and is used to perform up-conversion and down-conversion of signals. The digital transceiver circuit is located after the RF transceiver circuit and is used to perform quadrature up-conversion, analog-to-digital conversion, and digital-to-analog conversion of signals. The FPGA is used to receive and process baseband signals sent by the external host, perform multiple transmit beamforming and transmit them to the digital transceiver circuit; and to sample and process input analog signals, perform receive beamforming and transmit them to the external host.

[0007] The omnidirectional ground-to-air digital phased array communication system described above can achieve 360-degree omnidirectional radiation and reception of electromagnetic signals, has the function of transmitting and receiving multi-beam digital signals, has a high degree of integration, and can realize the miniaturization of the system. Attached Figure Description

[0008] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort: Figure 1 This is a structural cross-sectional view of an omnidirectional ground-to-air digital phased array communication system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an omnidirectional ground-to-air digital phased array communication system according to an embodiment of the present invention; Figure 3 This is a top view of a cylindrical antenna array according to an embodiment of the present invention; Figure 4 This is a schematic block diagram of an omnidirectional ground-to-air digital phased array communication system according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of a radio frequency transceiver motherboard according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a 2×8 microstrip antenna subarray according to an embodiment of the present invention. Detailed Implementation

[0009] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0010] One embodiment of the present invention provides an omnidirectional ground-to-air digital phased array communication system, such as... Figure 1 and Figure 2 As shown, the omnidirectional ground-to-air digital phased array communication system of this invention includes a cylindrical antenna array 1, an RF transceiver motherboard 2, a frequency synthesizer power supply board 3, a structural frame 4, and a cooling fan 5.

[0011] The bottom of the system is a cylindrical structural frame 4. The RF transceiver motherboard 2 is mounted on the structural frame 4, and the frequency synthesizer power supply board 3 is mounted inside the structural frame. Connectors between the RF transceiver motherboard 2 and the frequency synthesizer power supply board 3 facilitate data and power transmission. The cylindrical antenna array 1 is as follows... Figure 3 As shown, it is installed on the cylindrical structural frame 4 according to the conformal requirements and connected to the RF transceiver motherboard 2 with an SMP connector. The cooling fan 5 is installed at the bottom of the structural frame.

[0012] The cylindrical antenna array 1 comprises 32 2×8 microstrip antenna arrays with a total of 512 elements, employing microstrip vertically polarized antenna elements. Each printed circuit board includes two 1×8 microstrip antenna arrays, each using cosecant square-shaped antenna configurations. The microstrip antennas and cosecant square-shaped antenna networks are integrated onto the single printed circuit board. The 32 2×8 microstrip antenna arrays are vertically and conformally mounted on the cylindrical structural frame. The azimuth plane can achieve 360-degree scanning by activating antenna elements facing different directions. The elevation plane uses fixed cosecant square-shaped antenna configurations, enabling the formation of a uniform illumination area from near to far within the elevation plane. Figure 6 This is a schematic diagram of the structure of a 2×8 microstrip antenna array according to an embodiment of the present invention, wherein (a) is a 2×8 microstrip antenna array and (b) is the cocut squared shaping network of the inner layer.

[0013] The RF transceiver motherboard includes RF transceiver circuits, digital transceiver circuits, local oscillator power divider circuits, FPGA and peripheral circuits, clock distribution network, and optical modules. For example... Figure 4As shown, the RF transceiver circuit includes 32 RF transceiver SiPs, each integrating two transceiver conversion channels to down-convert Ku-band RF signals to S-band intermediate frequency signals. The digital transceiver circuit, located after the RF transceiver circuit, includes 16 digital transceiver SiPs, implementing quadrature up-conversion, up-conversion, and AD (analog-to-digital) and DA (digital-to-analog) functions. The local oscillator power divider circuit is located in the middle layer of the RF transceiver motherboard, distributing the local oscillator signal. The FPGA handles the reception, interpolation filtering, and DUC (Digital Up Converter) of the baseband signal transmitted from the external host; it also performs transmit beamforming and ultimately transmits the signal to the DAC (Digital-to-Analog Converter) for waveform playback; and it performs sampling, DDC (Digital Down Converter), and decimation filtering of the input analog signal; it also performs receive beamforming and transmits the signal to the external host via an optical module.

[0014] In one embodiment, the RF transceiver motherboard is as follows: Figure 5 As shown, the printed circuit board has a circular structure. The outermost layer consists of 32 radio frequency (RF) transceiver integrated units (SiPs), each integrating two transceiver conversion channels. The entire RF transceiver motherboard integrates 64 transceiver channels. Inside the 32 RF transceiver SiPs are 16 digital transceiver SiPs, each integrating four transmit channels and four receive channels. The FPGA is located at the center of the circular structure. When the system is in transmit mode, the FPGA completes the reception, interpolation filtering, and DUC of the baseband signal sent by the external host through the optical module, and completes the synthesis of multiple transmit beams and finally transmits them to the DAC in the digital transceiver SiP. The digital transceiver SiP completes the low-pass filtering and orthogonal upconversion of the DAC output signal to the S-band, and transmits the upconverted S-band signal to the RF transceiver SiP. The RF transceiver SiP upconverts the S-band signal output by the digital transceiver SiP to the Ku-band again and amplifies the power. The amplified Ku-band signal is finally transmitted to the 1×8 antenna subarray for external radiation. The entire cylindrical array includes 32 2×8 arrays with a total of 512 elements, and finally forms more than 5 digital transmit beams in space. When the system is in receiving mode, each RF transceiver SiP amplifies the Ku-band RF signal received from the 1×8 antenna subarray, downconverts it to the S-band, and transmits the downconverted S-band signal to the digital transceiver SiP. The digital transceiver SiP orthogonally downconverts the received S-band signal, low-pass filters it, and then performs AD sampling before finally sending the data to the FPGA. The FPGA performs digital multi-beam synthesis on the received 64 data streams and then transmits the baseband data of the received beam back through the optical module.

[0015] The frequency synthesizer power supply board includes a 100MHz crystal oscillator, a local phase-locked source (PLS) oscillator, a 256MHz PLS oscillator, and a power distribution circuit. The 100MHz crystal oscillator generates a 100MHz reference signal and outputs it to the local PLS oscillator and the 256MHz PLS oscillator to generate the local oscillator signal and the 256MHz clock signal, respectively. The power distribution circuit completes the first stage of high-efficiency voltage conversion through a DC-DC converter and the second stage of high-quality voltage conversion through an LDO (low dropout linear regulator), providing high-quality power to the RF transceiver motherboard.

[0016] Compared with the prior art, the omnidirectional ground-to-air digital phased array communication system of this invention has the following significant advantages: (1) By using conformal antenna technology, the antenna is installed on a cylindrical structure, thereby enabling the system to radiate and receive electromagnetic waves in all directions; (2) Since the 1×8 microstrip antenna subarray adopts cosecant square shaping, it can ensure that the UAV maintains stable communication function at a fixed altitude; (3) By using SiP packaging technology, the originally complex frequency conversion circuit and AD / DA circuit are integrated into the SiP module, which greatly improves the system integration and reduces the system size; (4) By using digital beamforming technology, more than 5 digital transceiver beamformings are realized.

[0017] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. An omnidirectional ground-to-air digital phased array communication system, characterized in that, It includes a cylindrical antenna array, an RF transceiver motherboard, a frequency synthesizer power supply board, a structural frame, and a cooling fan; The structural frame is cylindrical and located at the bottom of the system. The RF transceiver motherboard is mounted on the structural frame, and the frequency synthesizer power supply board is mounted inside the structural frame. Data and power are transmitted between the RF transceiver motherboard and the frequency synthesizer power supply board. The cylindrical antenna array is conformally mounted on the structural frame and connected to the RF transceiver motherboard. The cooling fan is mounted at the bottom of the structural frame. The cylindrical antenna array comprises multiple single printed circuit boards, each of which integrates a microstrip antenna array using cosecant square shaping. The azimuth plane of the cylindrical antenna array can achieve 360-degree scanning, while the elevation plane has fixed cosecant square shaping. The RF transceiver motherboard includes an RF transceiver circuit, a digital transceiver circuit, and an FPGA. The RF transceiver circuit is connected to a cylindrical antenna array and is used to perform up-conversion and down-conversion of signals. The digital transceiver circuit is located after the RF transceiver circuit and is used to perform quadrature up-conversion, analog-to-digital conversion, and digital-to-analog conversion of signals. The FPGA is used to receive and process baseband signals sent by the external host, perform multiple transmit beamforming and transmit them to the digital transceiver circuit; and to sample and process input analog signals, perform receive beamforming and transmit them to the external host.

2. The system as described in claim 1, characterized in that, The cylindrical antenna array consists of 32 individual printed circuit boards, each of which integrates two 1×8 microstrip antenna arrays, for a total of 512 antenna elements, which can form more than 5 digital transmission beams in space.

3. The system as described in claim 2, characterized in that, The radio frequency transceiver circuit includes 32 radio frequency transceiver SiPs, each integrating 2 transmit / receive conversion channels. The digital transceiver circuit is located after the radio frequency transceiver circuit and includes 16 digital transceiver SiPs, each integrating 4 transmit channels and 4 receive channels.

4. The system as described in claim 3, characterized in that, The printed circuit board of the RF transceiver motherboard has a circular structure. The outermost part of the circular structure consists of 32 RF transceiver SiPs, and the inner part of the 32 RF transceiver SiPs consists of 16 digital transceiver SiPs. The FPGA is located in the center of the circular structure.

5. The system as described in claim 4, characterized in that, The RF transceiver motherboard also includes a local oscillator power divider circuit, which is located in the middle layer of the RF transceiver motherboard to distribute the local oscillator signal.

6. The system as described in any one of claims 1-5, characterized in that, The frequency synthesizer power board includes a 100M crystal oscillator, a local oscillator phase-locked source, a 256M phase-locked source, and power distribution circuits, etc. The 100M crystal oscillator is used to generate a 100M reference signal and output it to the local oscillator phase-locked source and the 256M phase-locked source to generate a local oscillator signal and a 256M clock signal, respectively. The power distribution circuit performs the first stage of voltage conversion through a DC-DC converter and the second stage of voltage conversion through an LDO, providing power to the RF transceiver motherboard.

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