Complete polarization programmable antenna unit and design method

Abstract

The invention discloses a full-polarization programmable antenna unit and a design method. The full-polarization programmable antenna unit comprises a digital amplitude-phase programmable matching network module and a horn-shaped radiating antenna module, the digital amplitude-phase programmable matching network module comprises a T-type power divider, a 90-degree directional coupler, an FPGA (Field Programmable Gate Array) control module and two 360-degree digital phase shifters; amplitude adjustment is achieved through mutual cascade connection of a power divider, a 360-degree phase shifter and a 90-degree directional coupler, and programmable regulation and control are achieved through an FPGA control module. Amplitude and phase modulation of two polarization components of an antenna unit can be realized through a digital amplitude-phase programmable matching network module, specifically, the programmable matching network module used for feeding is connected with an antenna radiator through a radio frequency coaxial line, so that the complete polarization programmable capability is greatly improved, and the bandwidth of the antenna is improved. The polarization loss can be reduced and the polarization interference capability can be improved through variable polarization in a complex and changeable electromagnetic environment, and the method can also be applied to application scenes such as polarization imaging by combining a related algorithm in the aspect of polarization information identification.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wireless communication, and mainly relates to a full-polarization programmable antenna unit and a design method. BACKGROUND

[0002] The polarization of an antenna is an important parameter for describing the direction of an electric field of radiated or received electromagnetic waves, and the matching of the polarization of an antenna and the polarization of electromagnetic waves directly affects the signal transmission quality of a communication system, therefore, a traditional passive antenna is often designed to have an antenna polarization mode suitable for the characteristics of an application scenario. However, with the advent of the information age, the traditional antenna design with fixed transmitting or receiving polarization is difficult to meet the increasingly complex and fierce electromagnetic working environment, in order to adapt to the changing application scenarios and achieve higher data transmission rates, the polarization-adjustable antenna capable of dynamically switching the polarization state has gradually become one of the research hotspots in the field of antennas.

[0003] At present, the polarization-adjustable antenna has important research significance in application scenarios such as wireless communication, radar ranging and imaging, and navigation countermeasure technology. Among them, in the aspect of wireless communication technology, under the same frequency band, the polarization-adjustable antenna can establish different polarization channels by dynamically adjusting the polarization mode, so as to realize polarization multiplexing, improve the spectrum utilization rate and the maximum signal transmission rate; in the aspect of radar ranging, the polarization-adjustable antenna can effectively suppress the multipath fading caused by reflection and scattering by matching the best polarization direction of the receiving end with the signal, thereby improving the signal reception quality; for radar imaging, the amplitude and phase information of the target echo in the polarization domain can reflect the shape, posture and motion of the target object to a certain extent, which is conducive to improving the imaging accuracy; in the aspect of navigation countermeasure technology, in addition to the space domain, energy domain and frequency domain, the polarization-adjustable antenna can implement interference on the navigation equipment equipped with a multi-element adaptive zero antenna from the perspective of the polarization domain by transforming different polarizations, and in combination with the traditional interference modes in the space domain and time domain, the addition of the polarization domain interference can further improve the interference effect.

[0004] In order to meet the needs of the above different scenarios, domestic and foreign experts and scholars have carried out quite rich research on polarization reconfigurable antennas. Some polarization modes are realized by mechanical adjustment. However, due to the mechanical error caused by mechanical adjustment and the poor real-time adjustment, it is difficult to solve the problem, and the polarization electrically adjustable antenna gradually becomes a more mainstream research direction. Compared with mechanical adjustment, the polarization electrically adjustable antenna has the advantages of short polarization response time and flexible circuit erection. By using electric switches to interconnect adjacent radiating patch elements, the path of the surface current is changed to radiate different polarized waves by controlling the electric switches. These designs usually require a large number of PIN diodes to achieve more polarization state switching, which may increase the insertion loss and make the DC bias feed network more complex, which is not conducive to the further expansion of the polarization adjustable capability. Therefore, the limited polarization electrically adjustable range greatly limits the application and popularization of the polarization electrically adjustable antenna. SUMMARY

[0005] In order to overcome the above-mentioned deficiencies, the present application provides a full polarization programmable antenna unit and a design method, including 0-180 degree linear polarization, left and right circular polarization and arbitrary axis ratio and inclination angle of left and right elliptical polarization, which further expands the polarization adjustable range while ensuring the polarization response agility. In addition, the digital control based on FPGA effectively realizes the polarization programmable, which provides a relatively perfect hardware platform for the introduction of polarization control algorithm. Combined with the application requirements of polarization control capability in the fields of radar, communication and electronic countermeasure, it has quite broad application prospect.

[0006] The technical scheme adopted by the present application to solve its technical problems is: A full polarization programmable antenna unit, comprising a digital amplitude and phase programmable matching network module and a horn type radiating antenna module. The digital amplitude and phase programmable matching network module comprises a T-type power divider, a 90-degree directional coupler, an FPGA control module and two 360-degree digital phase shifters. The input end of the T-type power divider is connected with a radio frequency coaxial line, one output end of the T-type power divider is connected with one input end of the 90-degree directional coupler, the other output end of the T-type power divider is connected with the input end of the first 360-degree digital phase shifter, and the output end of the first 360-degree digital phase shifter is connected with the other input end of the 90-degree directional coupler. One output end of the 90-degree directional coupler is connected with the second 360-degree digital phase shifter, and the other output end of the 90-degree directional coupler and the output end of the second 360-degree digital phase shifter are two output ends of the digital amplitude and phase programmable matching network, which are respectively connected with two feed ports of the horn type radiating antenna module through radio frequency coaxial adapters. The 16-bit control pins of the FPGA control module are connected with the first 360-degree digital phase shifter and the second 360-degree digital phase shifter through DuPont wires, and the phase shift range of the 360-degree phase shifter is controlled through high and low levels.

[0007] The horn type radiation antenna module adopts a narrow-band horn antenna or a wide-band double-ridge horn antenna.

[0008] The output end of the amplitude and phase programmable matching network module is connected with the horn type radiation antenna module through a radio frequency coaxial adapter.

[0009] A full polarization programmable antenna is formed by periodically arranging a plurality of the full polarization programmable antenna units.

[0010] A design method of a full polarization programmable antenna unit comprises the full polarization programmable antenna unit, and the specific steps are as follows: (1) Amplitude and phase programmable matching network simulation: MATLAB software is used to simulate the amplitude and phase programmable matching network, the performance indicators of the T-type power divider, the 360-degree digital phase shift module and the 90-degree directional coupler are written into the MATLAB program as input data, the mathematical model about the radio frequency device is established for calculation, and the amplitude and phase data of the two-way output signals of the amplitude and phase programmable matching network are obtained; (2) Joint simulation of the amplitude and phase programmable matching network and the dual-polarized horn antenna: MATLAB-CST joint simulation method is used to jointly simulate the amplitude and phase programmable matching network and the dual-polarized horn antenna unit, and the E-plane and H-plane far-field radiation patterns of the antenna working in each polarization state are obtained through simulation; (3) Amplitude and phase programmable matching network test: first, the T-type power divider, the 360-degree digital phase shift module and the 90-degree directional coupler are cascaded to form the radio frequency circuit part of the amplitude and phase programmable matching network; then, the 16-bit high and low level control pins of the FPGA are connected to the two 360-degree digital phase shift modules through DuPont wires to realize the control circuit part of the amplitude and phase programmable matching network; finally, the amplitude and phase programmable matching network is tested by a vector network analyzer, and the test results are compared with the simulation results; (4) Antenna measurement: according to the simulation structure, a physical antenna is made and measured in a microwave darkroom, the amplitude and phase programmable matching network module is connected with the antenna, the antenna is placed on a rotating table in the microwave darkroom, the E-plane and H-plane far-field radiation patterns of the antenna working in each polarization state are tested, and the test results are compared with the simulation results.

[0011] Due to the adoption of the technical scheme as described above, the present application has the following advantages: The application provides a full polarization programmable antenna unit and a design method, a digital amplitude and phase programmable matching network is connected with a radio frequency device through a digital phase shifter and an FPGA control circuit, and the full range modulation of the amplitude and phase difference of two output signals can be realized only by controlling the phase modulation of the phase shifter, compared with the traditional method of controlling the amplitude ratio through an active amplifier and an attenuator, the method can reduce the combined power loss by 3dB at most, which is a very big technical advantage for the overall performance of the system, especially for reducing the transmission power consumption; secondly, in the field of polarization electrically adjustable antennas at present, the application expands the polarization control range to the agile control in the full polarization range, greatly improving the polarization reconfigurable ability of the existing antenna; in addition, the digital control based on the FPGA effectively realizes the polarization programmability, provides a relatively perfect hardware platform for the introduction of the polarization control algorithm, can be flexibly applied to polarization imaging, polarization interference and other application scenarios, and has wide application requirements. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 A unit architecture of an antenna according to the application; Figure 2 A schematic diagram of a digital amplitude and phase programmable matching network module; Figure 3 A schematic diagram of a horn type radiation antenna module; Figure 4 The amplitude curves of S21 and S31 of the digital amplitude and phase programmable matching network module of the application at 1.5GHz; Figure 5 The phase difference curves of S21 and S31 of the digital amplitude and phase programmable matching network module of the application at 1.5GHz; Figure 6 The reflection coefficient of the antenna unit of the application; Figure 7 The three-dimensional directional diagram of the antenna unit of the embodiment of the application; Figure 8 The two-dimensional surface current diagram of the antenna unit when the polarization is 90 degrees; Figure 9 The two-dimensional surface current diagram of the antenna unit when the polarization is left-handed circular polarization; Figure 10 The two-dimensional surface current diagram of the antenna unit when the polarization is right-handed circular polarization; Figure 11 The two-dimensional surface current diagram of the antenna unit when the polarization is left-handed elliptical polarization with an X-axis angle of 43 degrees and an axial ratio of 3; Figure 12 The E-plane unit far-field two-dimensional directional diagram in the left-handed circular polarization state; Figure 13 The H-plane unit far-field two-dimensional directional diagram in the left-handed circular polarization state; Figure 14 is a far-field two-dimensional pattern of a cross-polar E-plane element in a left-hand circular polarization state; Figure 15 is a far-field two-dimensional pattern of a cross-polar H-plane element in a left-hand circular polarization state. DETAILED DESCRIPTION

[0013] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0014] Reference Figure 1 and Figure 2 A full polarization programmable antenna element, the antenna adopts a modular design, including a digital amplitude-phase programmable matching network module 101 and a horn type radiating antenna module 102. The output end of the amplitude-phase programmable matching network module 101 is connected with the horn type radiating antenna module 102 through a radio frequency coaxial adapter.

[0015] The input end of the digital amplitude-phase programmable matching network module 101 is connected with a radio frequency coaxial line. When a radio frequency signal excites the digital amplitude-phase programmable matching network module 101, it can realize eight-bit (256 optional modes) digital control of arbitrary amplitude distribution ratio from 0:1 to 1:0 in amplitude and eight-bit (256 optional modes) digital control of 0 to 360 degree phase difference in phase of two-way radio frequency output signals. The two output ports of the digital amplitude-phase programmable matching network module are respectively connected with the radiating structure, and two polarization components orthogonal to each other are excited, so as to realize full polarization adjustment of 0 to 180 degree arbitrary linear polarization angle, left-hand or right-hand circular polarization and arbitrary axial ratio and left-hand or right-hand elliptical polarization of tilt angle.

[0016] The digital amplitude-phase programmable matching network module 101 includes a T-type power divider 1015, a 90-degree directional coupler 1014, an FPGA control module 1013 and two 360-degree digital phase shifters 1012-1; 1012-2. By cascading the power divider 1015, the 360-degree phase shifters 1012-1; 1012-2 and the 90-degree directional coupler 1014, programmable control is realized by the FPGA control module 1013.

[0017] In this embodiment, the input end of the T-shaped power divider 1015 is connected with a radio frequency coaxial line, one output end of the T-shaped power divider 1015 is connected with one input end of the 90-degree directional coupler 1014, and the other output end of the T-shaped power divider 1015 is connected with the input end of the first 360-degree digital phase shifter 1012-1, and the output end of the first 360-degree digital phase shifter 1012-1 is connected with the other input end of the 90-degree directional coupler 1014. In this embodiment, the 90-degree directional coupler 1014 is used to superimpose two signals with phase difference, and outputs signals with the same phase and amplitude in the range of 0:1 to 1:0 at the two output ends of the 90-degree directional coupler 1014. One output end of the 90-degree directional coupler 1014 is connected with the second 360-degree digital phase shifter 1012-2, and the other output end of the 90-degree directional coupler 1014 and the output end of the second 360-degree digital phase shifter 1012-2 are two output ends of the digital amplitude and phase programmable matching network 101, which are respectively connected with the two feed ports of the horn type radiating antenna module 102 through radio frequency coaxial adapters. In this embodiment, the 16-bit control pins of the FPGA control module 1013 are respectively connected with the first 360-degree digital phase shifter 1012-1 and the second 360-degree digital phase shifter 1012-2 through DuPont wires, and the phase shift range of the 360-degree phase shifter is controlled through high and low levels. 00000000 to 11111111 correspond to 0 to 360 degrees, and the phase accuracy is 1.4 degrees.

[0018] In this embodiment, the 360-degree digital phase shifter (1012-1; 1012-2) is a cascade of an 8-bit digital phase shift chip PE44820B-X and a compensation amplifier.

[0019] The feed position of the horn type radiating antenna module 102 is connected with the output end of the digital amplitude and phase programmable matching network module 101, and the horn type radiating antenna module 102 is used to radiate the radio frequency signal after amplitude and phase regulation in free space, and finally realizes the full polarization adjustment of the antenna unit with any linear polarization angle of 0 to 180 degrees, left-handed or right-handed circular polarization, and any axis ratio of left-handed or right-handed elliptical polarization through vector synthesis of polarization components.

[0020] In this embodiment, the digital amplitude and phase programmable matching network module 101 and the horn type radiating antenna module 102 are connected through a radio frequency coaxial adapter.

[0021] In this embodiment, the horn type radiating antenna module 102 includes but is not limited to a narrowband dual-polarized horn antenna or a wideband dual-polarized horn antenna in terms of implementation.

[0022] A full polarization programmable antenna is formed by a periodic array of a plurality of full polarization programmable antenna units.

[0023] A design method of a full polarization programmable antenna includes full polarization programmable antenna units, and the specific steps are as follows: (1) Amplitude and phase programmable matching network simulation: MATLAB software is used to simulate the amplitude and phase programmable matching network, the performance indicators of the T-type power divider, the 360-degree digital phase shift module and the 90-degree directional coupler are written into the MATLAB program as input data, the mathematical model about the radio frequency device is established for calculation, and the amplitude and phase data of the two-way output signals of the amplitude and phase programmable matching network are obtained; (2) Joint simulation of amplitude and phase programmable matching network and dual-polarized horn antenna: MATLAB-CST joint simulation method is used to jointly simulate the amplitude and phase programmable matching network and the dual-polarized horn antenna unit, and the E-plane and H-plane far-field radiation patterns of the antenna working in each polarization state are obtained through simulation; (3) Amplitude and phase programmable matching network test: first, the T-type power divider, the 360-degree digital phase shift module and the 90-degree directional coupler are cascaded to form the radio frequency circuit part of the amplitude and phase programmable matching network; then, the 16-bit high and low level control pins of the FPGA are connected to the two 360-degree digital phase shift modules through DuPont lines to realize the control circuit part of the amplitude and phase programmable matching network; finally, the amplitude and phase programmable matching network is tested by a vector network analyzer, and the test results are compared with the simulation results; (4) Antenna measurement: according to the simulation structure, the physical antenna is made and measured in the microwave darkroom, the amplitude and phase programmable matching network module is connected with the antenna, the antenna is placed on the rotating table in the microwave darkroom, the E-plane and H-plane far-field radiation patterns of the antenna working in each polarization state are tested, and the test results are compared with the simulation results.

[0024] Reference Figure 4In the specific design process of the FPGA-based amplitude and phase programmable matching network module 101, to realize simulation verification: the ideal performance indicators of the T-type power divider 1015, the 90-degree directional coupler 1014, the FPGA control module 1013, and the two 360-degree digital phase shifters 1012-1 and 1012-2 are written into a MATLAB program as input data, mathematical modeling is performed on them by using MATLAB software, the amplitude and phase data of the two-way output signals of the amplitude and phase programmable matching network, i.e., the amplitude and phase difference characteristics of S21 and S31 of the network, are obtained, and in order to simplify simulation calculation, the amplitude and phase data of the two-way output signals of the amplitude and phase programmable matching network module 101 are obtained at a frequency point of 1.5 GHz under the condition that the cascade of each radio frequency device is considered to be ideal matching with no loss. Specifically, with the continuous phase modulation of the first 360-degree digital phase shifter 1012-1, the abscissa changes from π / 2 to 3π / 2, and the amplitudes of S21 and S31 change accordingly, and as can be seen from the ordinate, |S21|: |S31| changes from 1:0 to 0:1, thereby verifying the full-amplitude adjustable performance of the digital amplitude and phase programmable matching network. Referring to Figure 5 The phase difference between S21 and S31 changes with the phase modulation of the second 360-degree digital phase shifter 1012-2, and the phase difference can be adjusted from 0 to 2π, thereby verifying the full-phase adjustable performance of the digital amplitude and phase programmable matching network. According to the electromagnetic theory that any electromagnetic wave in space can be synthesized by a pair of orthogonal linearly polarized waves with different amplitude ratios and phase differences, when the radiating structure is an orthogonal dual-polarized horn antenna 102, the amplitude and phase control performance of the digital amplitude and phase programmable matching network module 101 of the embodiment is sufficient to meet the feeding requirements of the full-polarization programmable antenna.

[0025] Referring to Figures 6-15 The amplitude and phase data obtained by MATLAB calculation are imported into the CST three-dimensional electromagnetic simulation software as the excitation characteristic parameters of the back-end radio frequency excitation source of the dual-polarized horn antenna 102, and MATLAB-CST joint simulation is performed.

[0026] Figure 6 To simulate the reflection coefficient of the obtained full-polarization programmable antenna unit, taking 90-degree linear polarization as an example, the simulation can obtain the reflection coefficient amplitude of the antenna unit, and it can be observed that in the range of 1.4 to 2 GHz, S11 floats in the range of 0.07 to 0.17, i.e., between -15 dB and -23 dB, so the matching state is good.

[0027] Referring to Figure 7 At this time, the radiation direction of the antenna unit is perpendicular to the horn aperture plane, indicating the radiation pattern characteristics of the embodiment. Referring to Figures 8-11 Where the flow direction of the surface current indicates the change of the polarization state, verifying the polarization adjustable function of the embodiment. Taking left-handed circular polarization as an example, it can be seen thatFigure 12 、 13 The two-dimensional radiation pattern of the E-plane and H-plane in the left-hand circular polarization state, the main lobe gain can reach 14.3dBi at 1.5GHz, and the side lobe level / main lobe gain are both lower than -20dB; Figure 14 and Figure 15 It can be seen that compared with the main polarization, the cross-polarization / main polarization is lower than -11dB, and the polarization purity is sufficient to meet the antenna design requirements, successfully verifying the feasibility of the full-polarization programmable unit design method.

[0028] During the design phase, the antenna unit's beam parameter requirements, operating frequency, and polarization are first analyzed. Based on the required frequency and polarization, a digital amplitude- and phase-programmable matching network module and a horn-shaped radiating antenna module are designed and integrated.

[0029] A fully polarization programmable antenna unit of the present invention can realize amplitude and phase modulation of the two polarization components of the antenna unit through a digital amplitude and phase programmable matching network module. Specifically, the programmable matching network module used for feeding is connected to the antenna radiator through an RF coaxial line, which greatly improves the full polarization programmability. It can reduce polarization loss and improve polarization interference capability by changing polarization in complex and changeable electromagnetic environments. It can also be combined with relevant algorithms for polarization information recognition and applied to application scenarios such as polarization imaging.

[0030] The parts not described in detail in the above content are prior art and are therefore not described in detail.

Claims

1. A fully polarized programmable antenna unit, characterized in that: It comprises a digital amplitude and phase programmable matching network module (101) and a horn-type radiation antenna module (102); The digital amplitude and phase programmable matching network module (101) comprises: a T-type power splitter (1015), a 90-degree directional coupler (1014), and an FPGA control module (1013); The input end of the T-type power splitter (1015) is connected to a radio frequency coaxial line, one output end of the T-type power splitter (1015) is connected to an input end of a 90-degree directional coupler (1014), the other output end of the T-type power splitter (1015) is connected to the input end of a first 360-degree digital phase shifter (1012-1), and the output end of the first 360-degree digital phase shifter (1012-1) is connected to the other input end of the 90-degree directional coupler (1014); One output end of the 90-degree directional coupler (1014) is connected to the second 360-degree digital phase shifter (1012-2); the other output end of the 90-degree directional coupler (1014) and the output end of the second 360-degree digital phase shifter (1012-2) are two output ends of the digital amplitude and phase programmable matching network (101), and are respectively connected to two feeding ports of the horn-type radiating antenna module (102) via radio frequency coaxial adapters; The 16-bit control pins of the FPGA control module (1013) are connected to the first 360-degree digital phase shifter (1012-1) and the second 360-degree digital phase shifter (1012-2) via DuPont lines, respectively, and the phase shift ranges of the first 360-degree digital phase shifter (1012-1) and the second 360-degree digital phase shifter (1012-2) are controlled by high and low levels.

2. The fully polarization programmable antenna unit according to claim 1, characterized in that: The horn-type radiating antenna module (102) adopts a narrowband horn antenna or a broadband double-ridged horn antenna.

3. The fully polarization programmable antenna unit according to claim 1, characterized in that: The output end of the amplitude and phase programmable matching network module (101) is connected to the horn-type radiation antenna module (102) via a radio frequency coaxial interface.

4. A fully polarized programmable antenna, characterized in that: It is formed by a periodic array arrangement of multiple fully polarization programmable antenna units as claimed in claim 1, 2 or 3.

5. A design method for a fully polarized programmable antenna unit, characterized by: The method comprises the fully polarization programmable antenna unit according to claim 1, 2 or 3, and the specific steps are as follows: (1) Amplitude and phase programmable matching network simulation: The amplitude and phase programmable matching network is simulated using MATLAB software. The performance indicators of the T-type power splitter, 360-degree digital phase shift module, and 90-degree directional coupler are written into the MATLAB program as input data. By establishing a mathematical model of the RF device for calculation, the amplitude and phase data of the two output signals of the amplitude and phase programmable matching network are obtained; (2) Joint simulation of the amplitude-phase programmable matching network and the dual-polarized horn antenna: Using the MATLAB-CST joint simulation method, the amplitude-phase programmable matching network and the dual-polarized horn antenna unit are jointly simulated. The far-field radiation patterns of the E-plane and H-plane of the antenna when working in each polarization state are obtained through simulation; (3) Amplitude and phase programmable matching network test: First, the T-type power splitter, 360-degree digital phase shift module and 90-degree directional coupler are physically cascaded to form the RF circuit part of the amplitude and phase programmable matching network; then, the 16-bit high and low level control pins of the FPGA are connected to the two 360-degree digital phase shift modules through DuPont lines to realize the control circuit part of the amplitude and phase programmable matching network; finally, the amplitude and phase programmable matching network is physically tested using a vector network analyzer, and the test results are analyzed and compared with the simulation results; (4) Antenna measurement: A physical antenna is made based on the simulated structure and measured in a microwave darkroom. The antenna is connected to an amplitude-phase programmable matching network module and placed on a rotating table in the microwave darkroom. The far-field radiation patterns of the E-plane and H-plane of the antenna are measured when the antenna is working in each polarization state. The test results are analyzed and compared with the simulation results.

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