Array antenna based on space-time modulation

Abstract

The utility model discloses an array antenna based on space-time modulation. The array antenna comprises a power distribution layer, an FPGA controller, a signal generator, a power amplifier and a plurality of reconfigurable antenna array elements. Each reconfigurable antenna array element is used for realizing dynamic regulation and control of radiation phase and amplitude; the power distribution layer is used for uniformly distributing radio frequency signals to each reconfigurable antenna array element; the FPGA controller is used for controlling the signal generator to generate a time-varying voltage signal according to the amplitude and phase distribution required by low sidelobe beam scanning; the signal generator is used for generating a time-varying voltage signal according to the amplitude and phase distribution scanned by the FPGA controller; and the power amplifier is used for amplifying the time-varying voltage signal generated by the signal generator and driving the reconfigurable antenna array element. The device is high in integration level, low in cost, capable of being produced in batches, easy to regulate and control, wide in angle response, capable of achieving dynamic scanning of wave beams at fundamental frequency and capable of achieving dynamic scanning of wave beams of harmonic waves.

Description

Technical Field

[0001] The utility model belongs to the technical field of antennas, and in particular relates to an array antenna based on time-space modulation. Background Art

[0002] Phased array antennas that implement functions such as beamforming and beam scanning require precise amplitude and phase excitation, which requires a large number of attenuators and phase shifters. By periodically controlling RF switches to introduce time factors into array antennas, the design and control can be greatly simplified. This is the so-called time modulated array (TMA). TMA improves the design freedom of array antennas by weighting amplitude and phase in the time dimension. By designing a time coding sequence, any required equivalent amplitude and phase can be achieved. However, TMA usually requires antenna array elements to have several different radiation states, which requires the use of phase shifters or phase delay lines and attenuators. At the same time, high-speed RF switches such as single-pole single-throw, single-pole multiple-throw or reconfigurable power dividers / combiners are required to implement time-coded modulation. Typically, each array element requires one or even more RF switches to switch the coding state. As the number of RF switches increases, the complexity of control also increases. In addition, multiple RF switches usually result in higher insertion loss. As the operating frequency band increases, the loss and cost of RF switches will also increase significantly. In addition, this separate design is difficult to apply in future highly integrated antenna systems. Therefore, designing a highly integrated, simple to control, and low-cost spatiotemporal modulation array antenna is very important for beam scanning and beamforming. Utility Model Content

[0003] The purpose of the utility model is to overcome the deficiencies of the prior art and to propose an array antenna based on time-space modulation, which is easy to integrate and mass produce, and can simplify the control system under the premise of realizing dynamic beam scanning of fundamental frequency and harmonic waves.

[0004] The design idea of ​​the array antenna based on time-space modulation provided by the utility model is:

[0005] The FPGA calculates the amplitude and phase distribution required for each array element according to the beam scanning angle, thereby controlling the signal generator to generate a control voltage that changes periodically over time. After amplification by the power amplifier, the diode integrated in the reconfigurable antenna array element is controlled to be periodically turned on and off to obtain the required amplitude and phase distribution, thereby realizing dynamic scanning of the beam and achieving characteristics that are easy to integrate and mass produce.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0007] An array antenna based on spatiotemporal modulation includes a power distribution layer, an FPGA controller, a signal generator, a power amplifier and a plurality of reconfigurable antenna array elements;

[0008] Each of the reconfigurable antenna array elements is used to achieve dynamic control of the phase and amplitude of electromagnetic wave radiation as a coding state of time modulation;

[0009] The power distribution layer is used to evenly distribute the radio frequency signal to each reconfigurable antenna array element;

[0010] The FPGA controller is used to control the signal generator to generate a time-varying voltage signal according to the amplitude and phase distribution required for low sidelobe beam scanning;

[0011] The signal generator is used to generate a time-varying voltage signal according to the amplitude and phase distribution scanned by the FPGA controller;

[0012] The power amplifier is used to amplify the time-varying voltage signal generated by the signal generator and drive multiple reconfigurable antenna array elements.

[0013] Preferably, the number of the plurality of reconfigurable antenna array elements is m*n.

[0014] Preferably, the reconfigurable antenna array element comprises a radiation layer, a feed layer, a metal reflector and a phase shift layer which are sequentially arranged from top to bottom, and the plurality of diodes and the plurality of metal structures are respectively arranged on the radiation layer;

[0015] A plurality of diodes are used to switch the metal structure on the radiation layer between anisotropy and isotropy;

[0016] The radiation layer is used to load multiple diodes and realize dynamic regulation of the electromagnetic wave radiation amplitude by controlling the conduction of different diodes as a coding state of time modulation;

[0017] The phase shift layer is used to load multiple diodes and realize dynamic regulation of the radiation phase by controlling the conduction of different diodes as a coding state of time modulation;

[0018] The feeding layer is used to feed the diode;

[0019] The metal reflector is used to radiate electromagnetic waves.

[0020] Compared with the prior art, the utility model has the following beneficial effects:

[0021] 1. The array antenna based on time-space modulation provided by the utility model uses only diodes and other devices, and does not require T / R components and high-speed RF switches, so the cost is low and it is easy to integrate and mass produce;

[0022] 2. The utility model can achieve more efficient beam scanning by using amplitude and phase coding at the same time, and greatly reduces the difficulty of designing the time modulation sequence required for low sidelobe scanning;

[0023] 3. The diode used in the utility model can operate in a higher frequency band, so it can be applied to high-frequency antenna design compared to traditional TMA;

[0024] 4. The diode used in the utility model has a faster response time and lower insertion loss, and can achieve more efficient beam scanning. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the structure of an array antenna based on time-space modulation provided by an embodiment of the utility model;

[0026] Figure 2 is a schematic diagram of a reconfigurable antenna array element in an embodiment of the present utility model;

[0027] Figure 3 It is a schematic diagram of the structure of the power distribution layer in the embodiment of the utility model;

[0028] Figure 4 The four radiation states of the array antenna based on time-space modulation provided by the embodiment of the utility model when different diodes in the radiation layer and the phase shift layer are turned on, the amplitudes are 0 and 1 respectively, and the phase states are 0°, 90°, 180° and 270° respectively;

[0029] Figure 5 The beam scanning performance of the array antenna based on time-space modulation provided by the embodiment of the utility model under the voltage modulation that changes periodically with time is 10°, 20°, 30°, 40°, 50° and 60°, respectively, wherein the beam scanning performance diagrams with sidelobe levels of -13dB and -30dB are respectively given;

[0030] Figure 6 A schematic diagram of the sideband levels of the array antenna based on time-space modulation provided by the embodiment of the utility model when no optimization algorithm is adopted and random coding and sequential coding are used for the time coding sequence;

[0031] Figure 7 A schematic diagram of the sideband levels of uniform period and non-uniform period for the reconfigurable antenna array element when the array antenna based on time-space modulation provided by the embodiment of the utility model is not using the optimization algorithm;

[0032] In the figure: 1. Radiating layer; 2. Feeding layer; 3. Metal reflector; 4. Phase shifting layer; 5. Diode; 6. Metal structure. DETAILED DESCRIPTION

[0033] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0034] like Figure 1 As shown, the embodiment of the utility model provides an array antenna based on time-space modulation, including a power distribution layer, an FPGA controller, a signal generator, a power amplifier and a plurality of reconfigurable antenna array elements; the number of the plurality of reconfigurable antenna array elements is m*n. The FPGA controller, signal generator and power amplifier in the embodiment of the utility model are all existing products, as long as they can realize their own basic functions, and this embodiment does not involve structural improvements to the above devices.

[0035] like Figure 2 As shown, each reconfigurable antenna array element is used to realize dynamic control of radiation phase and amplitude as the coding state of time modulation. Figure 2 Here, h1, h2 and h3 represent the thickness of the radiation layer 1, the metal reflector 3 and the phase shift layer 4 respectively. The values ​​of h2 and h3 are 0.1-2 mm, and the value of h1 is 0.01-0.1 times the wavelength.

[0036] Each reconfigurable antenna array element includes a radiation layer 1, a feed layer 2, a metal reflector 3 and a phase shift layer 4 which are arranged in sequence from top to bottom. A plurality of diodes 5 and a plurality of metal structures 6 are respectively arranged on the radiation layer 1. The number of diodes 5 in this embodiment is preferably 8, and the number of metal structures 6 is preferably 4. The metal structure 6 in this embodiment can be made of any metal material, such as copper, silver or gold, as long as it can realize the function of radiating electromagnetic waves.

[0037] Multiple diodes 5 are used to switch the metal structure 6 on the radiation layer 1 between anisotropy and isotropy; specifically, the state of the metal structure 6 on the radiation layer 1 is switched between anisotropy and isotropy by turning the diodes 5 on or off. By switching the state of the metal structure 6 on the radiation layer 1 between anisotropy and isotropy, it is possible to switch between radiating electromagnetic waves and not radiating electromagnetic waves.

[0038] The radiation layer 1 is used to load multiple diodes 5, and dynamically control the radiation amplitude by controlling the conduction of different diodes 5, as a coding state of time modulation; in this embodiment, the diodes 5 are used in the radiation layer of the reconfigurable antenna array element to replace the T / R components in the traditional phased array antenna and the high-speed radio frequency switches required in the traditional four-dimensional antenna array, so the cost is low and it is easy to integrate and mass produce; at the same time, the radiation phase and amplitude of the fundamental frequency and harmonics can be arbitrarily controlled by periodic voltage control in time, thereby realizing dynamic beam scanning at the fundamental frequency and harmonics; and in this embodiment, the reconstruction of the radiation phase and amplitude is mainly achieved by changing the surface current of the radiation layer by the diodes 5.

[0039] The phase shifting layer 4 is used to load a plurality of diodes 5 and realize dynamic regulation of the radiation phase by controlling the conduction of different diodes 5 as a coding state of time modulation.

[0040] The feeding layer 2 is used to feed the diode 5;

[0041] The metal reflective plate 3 is used to radiate electromagnetic waves.

[0042] The power distribution layer is used to evenly distribute the RF signal to each reconfigurable antenna array element. The power distribution layer in this embodiment is located at the bottom of the antenna array. A single signal is input to the power distribution layer, and the power can be evenly distributed to each reconfigurable antenna array element through the Wilkinson power divider, that is, only a single RF signal input is required to realize the feeding of all reconfigurable antenna array elements. The specific structure of the power distribution layer in this embodiment is as follows: Figure 3 shown.

[0043] The FPGA controller is used to control the signal generator to generate a time-varying voltage signal according to the amplitude and phase distribution required for low sidelobe beam scanning; in this embodiment, when low sidelobe scanning is realized at the base frequency through the FPGA controller, the optimization algorithm or not can be adopted; the implementation method without the optimization algorithm is to realize equivalent amplitude and phase through random time series encoding, and to realize sideband suppression by non-uniform periodic control for each adjustable antenna array element. When low sidelobe scanning is realized at the harmonic through the FPGA controller, the optimization algorithm or not can be adopted; the implementation method without the optimization algorithm is to use step-by-step phase control to make most of the energy concentrated on the first-order harmonic.

[0044] In this embodiment, the FPGA controller calculates the amplitude and phase distribution required for each reconfigurable antenna array element according to the beam scanning angle, and then calculates the time code sequence required to achieve the required amplitude and phase, thereby generating a control instruction to control the signal generator to generate a control voltage signal that changes periodically with time, and can use different modulation periods according to different reconfigurable antenna array elements, thereby realizing non-uniform periodic modulation of the antenna array. The voltage signal generated by the signal generator is amplified by the power amplifier to control the diode integrated in the reconfigurable antenna array element to periodically turn on and off to achieve switching of different radiation states, corresponding to the time code sequence generated by the FPGA, thereby realizing low sidelobe beam dynamic scanning and beamforming, and at the same time can well reduce the sideband level; and the power distribution layer transmits the RF signal to each reconfigurable antenna array element in phase. The reconfigurable antenna array element controls the state of the diode through the voltage signal, and then controls the direction of the surface current on the metal structure to achieve the regulation of the radiation phase (0°, 90°, 180° and 270°); when all diodes are in the off state, the antenna does not radiate, and the radiation phase is 0 at this time.

[0045] A signal generator for generating a time-varying voltage signal according to the amplitude and phase distribution scanned by the FPGA controller;

[0046] The power amplifier is used to amplify the time-varying voltage signal generated by the signal generator and drive multiple reconfigurable antenna array elements.

[0047] The working method of the array antenna based on time-space modulation provided by the embodiment of the utility model comprises the following steps:

[0048] 1. The FPGA controller calculates the radiation phase and amplitude required for each reconfigurable antenna array element according to the preset beam scanning angle, and then calculates the time coding sequence required to achieve the required amplitude and phase, and generates a control instruction control signal generator to generate a control voltage signal that changes periodically with time;

[0049] 2. The signal generator generates a voltage signal that changes periodically over time, which is amplified by the power amplifier and transmitted to the reconfigurable antenna array;

[0050] 3. The power distribution layer delivers equal and in-phase feeds to the reconfigurable antenna array, and then achieves equivalent radiation phase and amplitude through voltage signal control to realize dynamic beam scanning.

[0051] The technical effect of the array antenna based on spatiotemporal modulation provided by this embodiment is verified and explained below through simulation and experiment.

[0052] 1. Simulation conditions:

[0053] In this embodiment, the entire reconfigurable antenna array element is assumed to be in free space, and waveguide port excitation is used. The radiation amplitude and phase of the reconfigurable antenna array element of this embodiment under different states are simulated using electromagnetic simulation software. After the basic simulation performance of the unit is obtained, the equivalent phase and amplitude under time series simulation are simulated using MATLAB software to further realize the simulation of dynamic beam scanning.

[0054] 2. Simulation content and results:

[0055] Simulation 1

[0056] The 6.1-6.8 GHz band is selected in the C band to simulate the performance of the array antenna based on time-space modulation provided in this embodiment. The diodes of the radiation layer and the phase shift layer are respectively turned on and off, thus corresponding to five states, namely, the radiation amplitude is 1, the phase is 0°, 90°, 180°, 270° and the radiation amplitude is 0. The results are as follows: Figure 4 shown; through Figure 4 It can be seen that when time series modulation is adopted, the reconfigurable antenna array element has five basic radiation states; therefore, the array antenna based on time-space modulation provided in this embodiment can realize dynamic control of radiation amplitude and phase.

[0057] Simulation 2

[0058] The five basic radiation states of the array antenna provided in this embodiment are used for random time series encoding, and non-uniform periodic modulation is used to achieve beam scanning; at the same time, the radiation amplitude is used to achieve low sidelobe scanning by using Chebyshev distribution or Taylor distribution. The results are as follows: Figure 5 As shown; therefore, the array antenna based on spatiotemporal modulation provided in this embodiment can achieve beam scanning with low side lobes.

[0059] Simulation 3

[0060] The time coding sequence simulates the normalized radiation power spectrum of the antenna array at 6.4 GHz using sequential coding and random coding. Figure 6 As shown, through Figure 6 It can be seen that when random coding is used, the energy of the harmonics can be effectively curbed, while the energy of the center frequency can be kept unchanged. This is because random coding can distribute all harmonic energy more evenly on the power spectrum, thereby reducing the maximum value of the harmonic energy; therefore, the array antenna based on time-space modulation provided in this embodiment can achieve suppression of the sideband level through random coding.

[0061] Simulation 4

[0062] The time coding sequence uses uniform periodic modulation and non-uniform periodic modulation to simulate the normalized radiation power spectrum of the antenna array at 6.4 GHz, such as Figure 7As shown, through Figure 7 It can be seen that when non-uniform periodic modulation is used, the energy of harmonics can be effectively suppressed. This is because the frequencies of harmonics generated by various array elements are different when non-uniform periodic modulation is used, and they cannot be superimposed in space. Therefore, this embodiment can achieve sideband level suppression by adopting non-uniform periodic modulation on the reconfigurable antenna array elements.

[0063] The above simulation results indicate that the array antenna based on time-space modulation provided in this embodiment realizes dynamic beam scanning at any angle, can achieve low sidelobe scanning and good sidelobe suppression through random coding and non-uniform periodic modulation, and can exhibit good and stable beam scanning effects without using expensive T / R components and high-speed RF switches.

[0064] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An array antenna based on time-space modulation, characterized in that: It includes a power distribution layer, an FPGA controller, a signal generator, a power amplifier, and multiple reconfigurable antenna array elements; Each of the reconfigurable antenna array elements is used to achieve dynamic control of the phase and amplitude of electromagnetic wave radiation as a coding state of time modulation; The power distribution layer is used to evenly distribute the radio frequency signal to each reconfigurable antenna array element; The FPGA controller is used to control the signal generator to generate a time-varying voltage signal according to the amplitude and phase distribution required for low sidelobe beam scanning; The signal generator is used to generate a time-varying voltage signal according to the amplitude and phase distribution scanned by the FPGA controller; The power amplifier is used to amplify the time-varying voltage signal generated by the signal generator and drive multiple reconfigurable antenna array elements.

2. The array antenna based on time-space modulation according to claim 1, characterized in that: The number of the plurality of reconfigurable antenna array elements is m*n.

3. The array antenna based on time-space modulation according to claim 1, characterized in that: Each of the reconfigurable antenna array elements comprises a radiation layer (1), a feed layer (2), a metal reflector (3) and a phase shift layer (4) which are arranged in sequence from top to bottom, and a plurality of diodes (5) and a plurality of metal structures (6) are respectively arranged on the radiation layer (1); A plurality of diodes (5) are used to switch the metal structure (6) on the radiation layer (1) to be anisotropic or isotropic; The radiation layer (1) is used to load a plurality of diodes (5), and dynamically adjust the amplitude of electromagnetic wave radiation by controlling the conduction of different diodes (5), as a coding state of time modulation; The phase shift layer (4) is used to load a plurality of diodes (5) and realize dynamic regulation of the radiation phase by controlling the conduction of different diodes (5) as a coding state of time modulation; The feeding layer (2) is used to feed the diode (5); The metal reflection plate (3) is used for radiating electromagnetic waves.

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