Time-modulated dual-polarized array antenna system and its beam steering method

Abstract

The application relates to the technical field of array antennas and time modulation phased array, in particular to a time modulation dual-polarized array antenna system and a beam control method thereof, and is further provided with a radio frequency switch module and an FPGA control module; the radio frequency switch module is internally provided with a plurality of radio frequency switches; two or more ports of the same polarization direction or the same working frequency band of the dual-polarized array antenna form a port group; each port group is provided with a radio frequency signal by a corresponding power divider and is connected to each array port through a corresponding radio frequency switch; the FPGA control module outputs effective time sequence control signals to the port groups participating in the work according to the currently selected working frequency band and polarization state, or outputs different time sequence control signals to different port groups; compared with the prior art, the dependence on phase shifters and attenuators in the traditional phased array can be reduced, and the application has the advantages of simple structure, low cost and convenient processing and testing.

Description

Technical Field

[0001] This invention relates to the field of array antennas and time-modulated phased array technology, specifically to a time-modulated dual-polarized array antenna system and its beam control method based on RF switches and FPGA timing control, which can reduce the dependence on phase shifters and attenuators in traditional phased arrays, and has the characteristics of simple structure, low cost, easy processing and testing, and flexible control. Background Technology

[0002] A phased array antenna is an antenna system that achieves beam scanning and pattern modulation by controlling the amplitude and phase of each antenna element in the array. It is widely used in radar, communication, navigation, and radio frequency sensing. Traditional phased array antennas typically rely on radio frequency devices such as phase shifters, attenuators, and T / R modules to control the amplitude and phase of each array element. While this approach can achieve good beam control capabilities, as the number of array elements increases, the number of radio frequency channels, the number of phase shifters, and the complexity of the control circuitry in the system increase significantly, leading to increased system cost, size, and debugging difficulty.

[0003] Time-modulated arrays are an array antenna technology that utilizes the time dimension to achieve equivalent amplitude and phase control of the array. This technology typically achieves different equivalent excitations for different antenna elements in the array by periodically controlling the on and off states of radio frequency switches, thereby forming a controllable radiation pattern under different harmonic components or operating conditions. Compared to traditional phased arrays, time-modulated arrays can replace some analog amplitude and phase control devices with digital timing control, offering advantages such as relatively simple structure, flexible control, and lower cost.

[0004] Existing time-modulated array systems are mostly studied using single-polarization, single-band, or ideal array models. In practical engineering applications, array antennas often need to consider factors such as multi-band, multi-polarization, port isolation, fabrication and assembly, and actual connection. For dual-polarization array antennas, each antenna element typically requires two orthogonal polarization ports, and the operating frequency band, feeding method, and array combining method differ for different polarization ports. If traditional feeding networks or simple switch control structures are directly used, problems such as complex port connections, difficult feeder layout, reduced polarization isolation, inconvenient interface installation, and difficulty in matching switch control with array ports can easily arise.

[0005] Furthermore, the engineering implementation of time-modulated arrays involves not only the antenna elements themselves, but also multiple components such as power divider networks, RF switches, control circuits, SMA interfaces, reflectors, and structural fixing methods. Existing research often focuses on time modulation theory or switching timing optimization, while neglecting the overall collaborative design of dual-polarized array antenna structures suitable for practical fabrication and testing, port grouping methods, RF switch connection methods, and FPGA control interfaces.

[0006] Further research reveals that existing time-modulated array technologies have disclosed schemes for using FPGAs to control RF switches or time-modulation units to achieve amplitude and phase weighting of the feed network, as well as schemes for achieving independent control of multiple beams based on time-modulation sideband allocation and sideband delay adjustment. These schemes are effective in reducing the reliance on analog amplitude and phase control devices such as phase shifters and attenuators in traditional phased arrays, but their technical focus is mainly on the complex weighting of the time-modulated feed network itself, or on independent control methods for beams corresponding to different time-modulation sidebands.

[0007] However, in the engineering implementation of dual-polarized array antennas, in addition to time modulation timing design, it is also necessary to simultaneously solve the correspondence between ports of different operating frequency bands, ports of different polarizations, power divider feed branches, RF switch channels, and FPGA control signals. For array structures with multiple dual-polarized antenna elements, simply using existing complex weighted feed networks or multi-sideband beam control methods cannot directly solve the problems of a large number of ports, complex polarization port distribution, different control objects in different frequency bands and polarization states, unclear connection relationships between external power dividers and RF switches, and difficulty in unifying prototype processing and testing interfaces in dual-polarized arrays. Therefore, it is still necessary to propose a time modulation control structure for dual-polarized array antenna systems to establish a clear system correspondence between array port grouping, power divider feed networks, RF switch modules, and FPGA control modules. Summary of the Invention

[0008] This invention addresses the shortcomings and deficiencies of existing technologies by proposing a time-modulated dual-polarized array antenna system and its beam control method based on RF switches and FPGA timing control. This system reduces the dependence on phase shifters and attenuators in traditional phased arrays and features simple structure, low cost, ease of fabrication and testing, and flexible control.

[0009] Compared with existing technical solutions that mainly focus on time-modulated complex weighted feed networks or multi-sideband beamforming methods, the focus of this invention is not on proposing a single general time-modulated feed unit, nor on forming multiple independent beams through different time-modulated sidebands, but on establishing the corresponding control relationship between array antenna port groups, power divider feed branches, RF switch channels, and FPGA control signals for the actual system configuration of dual-polarized array antennas.

[0010] Specifically, this invention groups multiple RF ports of a dual-polarized array antenna according to their operating frequency band and polarization, so that ports operating in the same frequency band or polarization form corresponding port groups. Each port group obtains RF signals through a corresponding power divider feed network and connects to the array antenna port through a corresponding RF switch. The FPGA control module outputs effective time modulation control signals only to the participating port groups, or outputs independent time modulation control signals to different port groups, based on the current operating frequency band, polarization, and target beam direction. By configuring timing parameters such as modulation period, conduction start time, conduction duration, duty cycle, and relative delay, the participating array ports can form the equivalent amplitude distribution and equivalent phase distribution required for the target beam within one time modulation period.

[0011] Therefore, this invention does not merely utilize FPGA for ordinary on / off control of RF switches, but rather collaboratively designs the dual-polarized array port grouping, power divider feed network, RF switch module, and FPGA timing control module to form a reconfigurable time-modulated feed system suitable for dual-polarized array antennas. This system can improve the control precision, connectivity feasibility, and prototype testing convenience of dual-polarized arrays under different frequency bands, polarization states, and beam directions while reducing reliance on traditional phase shifters and attenuators.

[0012] This invention achieves its purpose through the following measures: A time-modulated dual-polarized array antenna system includes a dual-polarized array antenna, a radio frequency (RF) signal source, and a power divider feed network. The dual-polarized array antenna contains multiple dual-polarized antenna elements. The system is characterized by further including an RF switch module and an FPGA control module. The RF switch module contains multiple RF switches, grouping the ports of the dual-polarized array antenna according to their operating frequency band and polarization mode. Each port group corresponds one-to-one with a corresponding power divider in the power divider feed network, a corresponding RF switch in the RF switch module, and a corresponding control signal output from the FPGA control module. Two or more ports of the dual-polarized array antenna in the same polarization direction or operating frequency band constitute a port group. Each port group receives an RF signal from a corresponding power divider, which is then connected to the array ports via a corresponding RF switch. The FPGA control module outputs valid timing control signals only to the participating port groups, or outputs different timing control signals to different port groups, depending on the currently selected operating frequency band and polarization state.

[0013] In this invention, an RF signal source inputs an RF signal to a power divider feed network. After power distribution processing by the power divider feed network, the signal is sent to an RF switch module. The RF switch module, equipped with multiple RF switches, then sends the signal to a dual-polarized array antenna through controlled power feeding processing. An FPGA control module is also included. The FPGA control module outputs multiple periodic digital control signals to the RF switch module. Each periodic digital control signal controls the on / off state of one RF switch. By setting the modulation period, on-start time, on-duty time, and duty cycle parameters, multiple synchronous control signals are output, enabling each port of the array antenna to form a preset equivalent amplitude and phase distribution within the time modulation period to achieve the target beam pattern.

[0014] The periodic digital control signal output by the FPGA module of this invention is a rectangular pulse signal or a square wave signal, and its parameters include the modulation period. , conduction start time Conduction duration Duty cycle and relative delay ,in Indicates the first RF switch, in one modulation cycle within, when When the path control signal is high, the corresponding RF switch is turned on, and the RF signal of the corresponding branch in the power divider feed network is transmitted to the corresponding port of the array antenna; when the first... When the circuit control signal is low, the corresponding RF switch is off, and this port does not participate in radiation at the current moment or is in a matched absorption state. Here, the modulation period of the periodic control signal output by the FPGA control module is assumed to be... The corresponding modulation frequency It can be represented as: The duty cycle satisfy Used to regulate the first The equivalent excitation amplitude of each array port; the conduction start time Or the relative delay between various control signals Used to adjust the first The equivalent excitation phase of each array port.

[0015] In the power divider feeder network of this invention, the power divider is configured as 1 to 4 or 1 to 2, respectively corresponding to dual-frequency operation, to ensure that the dual-frequency signals are evenly distributed and the amplitude is matched. The output terminal of the power divider is electrically connected to the radio frequency switch, which is used to distribute individual signals to each antenna port in groups.

[0016] In the power divider feeder network of this invention, the power divider is configured as 1 to 4 or 1 to 2, respectively corresponding to dual-frequency operation, to ensure that the dual-frequency signals are evenly distributed and the amplitude is matched. The output terminal of the power divider is electrically connected to the radio frequency switch, which is used to distribute individual signals to each antenna port in groups.

[0017] The radio frequency switch of the present invention includes 2N radio frequency switches, where N is the number of antenna elements in the dual-polarized array antenna. The 2N radio frequency switches are connected to the antenna elements in pairs. Taking eight radio frequency switches as an example, the output terminal of the first radio frequency switch is connected to the first antenna element P1, the output terminal of the second radio frequency switch is connected to the second antenna element P3, the output terminal of the third radio frequency switch is connected to the third antenna element P5, the output terminal of the fourth radio frequency switch is connected to the fourth antenna element P7, the output terminal of the fifth radio frequency switch is connected to the first antenna element P2, the output terminal of the sixth radio frequency switch is connected to the second antenna element P4, the output terminal of the seventh radio frequency switch is connected to the third antenna element P6, and the output terminal of the eighth radio frequency switch is connected to the fourth antenna element P8.

[0018] The dual-polarized array antenna of the present invention includes at least one dual-polarized antenna element. Each element includes a stacked structure: an upper radiating patch, an air layer, a slotted ground plane, a feed dielectric board, a feed line, and a lower reflector. The radiating patch has two vertical H-shaped slots below it, and the feed line is electrically connected to the feed board through the slots. Multiple antenna elements are arranged in a 2×2 array, and the ports of each element are numbered P1-P8. The antenna element feed line is a straight microstrip line of equal width and is arranged perpendicular to the corresponding slot. The feed line length is optimized so that the upper radiating patch completely covers the slot.

[0019] This invention proposes a beam control method for a time-modulated dual-polarized array antenna system, characterized by the following steps: Step 1: Select the corresponding array port group based on the signal operating frequency band and polarization. Based on the current operating frequency band and polarization state, select the port group to participate in the operation from multiple RF ports of the dual-polarized array antenna. Different polarization port groups correspond to different polarization radiation states, and different operating frequency bands correspond to corresponding feed ports or feed branches. Step 2: Determine the target beam pointing or target pattern requirements, and based on the array element positions, operating wavelength, and target beam pointing, determine the equivalent excitation amplitude and equivalent excitation phase required for each array port. For the first... Each array port has an equivalent excitation amplitude denoted as . The equivalent excitation phase is denoted as ; Step 3: Convert the required equivalent phase difference of each port into the conduction start time difference of the corresponding RF switch control signal; simultaneously, set the conduction duration or duty cycle of each control signal according to the amplitude weighting requirements of the target pattern, and generate periodic control signals corresponding to each array port by the FPGA control module. The periodic control signals are rectangular pulse signals or square wave control signals, and each periodic control signal controls the conduction and cutoff of one RF switch; the parameters of the periodic control signal include the time modulation period. , conduction start time Conduction duration Duty cycle and relative delay ,in Indicates the first RF switch, and duty cycle Each periodic control signal has a unified clock reference and can be independently configured according to the preset beam direction. Step 4: Based on the preset beam pointing or pattern requirements, set the timing parameters of each periodic control signal according to the preset mapping rules: First, determine the equivalent excitation phase required for each array port based on the target beam pointing, array unit position, and wavelength corresponding to the current operating frequency band; then, determine the equivalent excitation amplitude required for each array port based on the amplitude weighting requirements of the target pattern. Each array port converts its required equivalent excitation phase into the on-start time of the corresponding control signal. or relative delay The required equivalent excitation amplitude is converted into the conduction duration of the corresponding control signal. or duty cycle When the target beam direction changes, the FPGA control module recalculates or calls the pre-stored timing parameter table according to the new target beam direction, updating the on-start time or relative delay of each control signal. This changes the equivalent phase difference between array ports; when the sidelobe level, main lobe width, or amplitude weighting requirement of the target pattern changes, the FPGA control module updates the conduction duration of each control signal. or duty cycle This is done to change the equivalent amplitude distribution between array ports, thereby enabling the selected array port group to form an equivalent amplitude and phase distribution corresponding to the target beam pattern within one time modulation period; Step 5: The radio frequency signal is distributed to multiple branches through the power divider network and connected to the selected array port group through the radio frequency switch module. Under the action of the FPGA control signal, the radio frequency switch module is turned on or off according to the preset timing, so that each array port obtains the corresponding equivalent excitation amplitude and equivalent excitation phase within a time modulation period, thereby enabling the array to form the target beam pattern in the corresponding operating frequency band and polarization state.

[0020] This invention differs from methods that only use fixed power divider networks or simple RF switch on / off control. It achieves this difference through the following technical means: based on the target beam pointing or target radiation pattern requirements, the equivalent amplitude and phase distribution required for each array port is first determined. Then, this equivalent amplitude and phase distribution is converted into the on-start time, on-duty time, duty cycle, and relative delay of the corresponding RF switch control signal. The FPGA control module generates multiple synchronous timing signals, thereby realizing reconfigurable beam control of the dual-polarized array antenna.

[0021] This invention has the following advantages: First, it does not simply connect a dual-polarized array antenna to an RF switch. Instead, it groups the different frequency band ports and polarization ports of the array antenna, and connects each port group to the control system through a power divider network and the corresponding RF switch branch. The FPGA control module outputs periodic control signals with preset timing parameters to each RF switch based on the current operating frequency band, polarization state, and target beam pattern. By adjusting the conduction start time, conduction duration, duty cycle, and relative delay of different branches, each array port obtains the corresponding equivalent excitation amplitude and equivalent excitation phase within one time modulation period. Therefore, this invention can achieve array pattern reconstruction and beam pointing adjustment using the same time modulation control architecture across different operating frequency bands and polarization states. Secondly, this invention outputs multiple periodic timing signals through an FPGA control module to independently or in groups control the RF switches located between the power divider network and the array ports. Each RF switch corresponds to an array port or a preset port branch. The FPGA control module changes the conduction start time, conduction duration, duty cycle, and relative delay of the corresponding control signal to enable each array port to obtain different equivalent excitation amplitudes and equivalent excitation phases within the time modulation period. Therefore, this invention does not require traditional phase shifters and attenuators in each array channel. Instead, it uses the switching timing parameters to achieve equivalent amplitude and phase modulation, thereby reducing the number of analog amplitude and phase control devices, reducing system complexity, hardware cost, and debugging difficulty.

[0022] Third, this invention groups the array ports according to their operating frequency band and polarization, and assigns each port group to a corresponding power divider feed network, RF switch branch, and FPGA control signal. Specifically, in a dual-polarized array antenna, multiple ports with the same polarization direction or operating frequency band constitute a port group. Each port group is supplied with RF signals by a corresponding power divider and connected to each array port via a corresponding RF switch. The FPGA control module outputs valid timing control signals only to the participating port groups, or outputs different timing control signals to different port groups, based on the currently selected operating frequency band and polarization state. Thus, a clear one-to-one correspondence is formed between the power divider feed network, the RF switch module, and the array antenna ports, avoiding the problems of confusing port connections, unclear control objects, and difficult debugging in dual-polarized arrays.

[0023] Fourth, the antenna unit of this invention adopts a slotted coupling feed structure as a preferred implementation. Coupling slots corresponding to the two orthogonal polarization directions are provided below the radiating patch, and two microstrip feed lines are electromagnetically coupled to the same radiating patch through their respective coupling slots. The two polarization feed channels are structurally independent and connected to their respective array ports, facilitating subsequent connection to the power divider feed network and RF switch module. By adjusting the size of the coupling slots, feed line positions, air gap height, and radiating patch size, the radiation performance of the two operating frequency bands and the two polarization ports can be optimized respectively, and the mutual coupling between the orthogonal polarization ports can be reduced. Thus, this structure not only enables dual-polarization radiation but also provides an independent and easily accessible port foundation for RF switch time modulation control. Fifth, this invention incorporates an SMA RF interface, reflector, mounting holes, and interlayer air gap control structure in the array structure to meet actual processing, assembly, and testing requirements. Each array port is led out to the corresponding SMA RF interface via a microstrip feed line, enabling the array antenna to be directly connected to external power dividers, RF switch modules, and test equipment. A reflector is positioned below the array to improve its unidirectional radiation characteristics and serve as mechanical support for the multi-layer structure. Mounting holes are used to fix the relative positions of the radiating layer, slotted ground plane, feed layer, and reflector, ensuring stable air gap height and port connection relationships after fabrication and assembly. Therefore, this invention does not merely remain a theoretical array model but rather forms a dual-polarization time-modulated array antenna structure suitable for prototype fabrication, modular connection, and practical verification.

[0024] Sixth, the time modulation control structure of this invention is scalable. The number of RF switches in the RF switch module can be expanded according to the number of array antenna elements and polarization ports. Each newly added array port can be connected to the system according to the correspondence of "power branch - RF switch - array port - FPGA control signal". For arrays with different numbers of array elements, the FPGA control module only needs to add the corresponding number of control channels and reconfigure the timing parameters of each control signal according to the target beam direction to form a new equivalent amplitude and phase distribution. Therefore, this invention is not only applicable to 2×2 dual-polarization arrays, but can also be extended to dual-polarization time modulation array systems with more array elements, and has good structural scalability and beam control flexibility. Attached Figure Description

[0025] Appendix Figure 1 This is a system principle block diagram of the present invention.

[0026] Appendix Figure 2 This is an exploded structural diagram of a single dual-polarized antenna element in this invention.

[0027] Appendix Figure 3 This is a schematic diagram of the exploded structure of the 2×2 dual-polarized array antenna in this invention.

[0028] Appendix Figure 4 This is a system principle block diagram in an embodiment of the present invention.

[0029] Appendix Figure 5 This is a schematic diagram of the radio frequency switch and port time modulation principle in an embodiment of the present invention.

[0030] Appendix Figure 6 This is a simulation diagram in an embodiment of the present invention.

[0031] Appendix Figure 7 These are the simulation and measurement results of the radiation pattern of the array antenna under different control states in the embodiments of the present invention. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] like Figure 1 As shown, the dual-polarized time-modulated array antenna system provided in this example includes an RF signal source, a power divider feed network, an RF switch module, a dual-polarized array antenna, an FPGA control module, and a host computer or control computer.

[0034] The radio frequency (RF) signal source is used to generate the RF signals required for the array antenna to operate. In this example, the RF signal source includes a first-band RF signal source and a second-band RF signal source, which are used to generate RF signals in the first operating frequency band and the second operating frequency band, respectively. The first operating frequency band can correspond to the first polarization port group of the array antenna, and the second operating frequency band can correspond to the second polarization port group of the array antenna.

[0035] The power divider network is positioned between the RF signal source and the RF switch module to distribute the input RF signal into multiple output signals. In this example, the power divider network includes two 1×4 power dividers, one of which connects to the first polarization port group and the other connects to the second polarization port group. The multiple outputs of the power divider are connected to the corresponding RF switch inputs in the RF switch module.

[0036] The RF switch module is positioned between the power divider feed network and the dual-polarized array antenna. The RF switch module includes multiple RF switches. The RF input of each RF switch is connected to the output of the power divider feed network, and the RF output is connected to the corresponding RF port of the array antenna. The control terminal is connected to the FPGA control module. By controlling the on / off state or channel selection state of the RF switches, the equivalent excitation state of each array port at different times can be changed.

[0037] The FPGA control module generates multiple time-modulated control signals corresponding to each RF switch and outputs these signals to the control terminal of the RF switch module. The host computer or control computer sends target operating status instructions to the FPGA control module. These instructions include at least one of the following: operating frequency band, polarization mode, target beam pointing, and pattern amplitude weighting requirements.

[0038] After receiving the target operating status command, the FPGA control module first determines the array port group to participate in the operation based on the operating frequency band and polarization mode; then, it determines the equivalent excitation phase required for each array port in the array port group based on the target beam direction, and determines the equivalent excitation amplitude required for each array port based on the radiation pattern amplitude weighting requirements; then, according to the preset mapping rules, it converts the equivalent excitation phase into the conduction start time or relative delay of the corresponding RF switch control signal, and converts the equivalent excitation amplitude into the conduction duration or duty cycle of the corresponding RF switch control signal.

[0039] The time modulation control signals output by the FPGA control module are multiple synchronous periodic pulse signals or square wave signals. Each time modulation control signal has a unified modulation period and clock reference, and has independently configurable conduction start time, conduction duration, duty cycle, and relative delay. Each time modulation control signal controls the conduction and cutoff of a radio frequency switch, so that the corresponding array port obtains a preset equivalent excitation state within one time modulation period.

[0040] When the target beam pointing, operating frequency band, or polarization changes, the FPGA control module recalculates the timing parameters based on the new target operating state, or calls a pre-stored timing parameter table to update the multi-channel time modulation control signals of the corresponding port group. Therefore, the RF switch module does not simply perform on / off control, but under the timing encoding generated by the FPGA control module, it enables the dual-polarized array antenna to form corresponding equivalent amplitude and phase distributions under different frequency bands, different polarization states, and different target beam pointing.

[0041] like Figure 2 and Figure 3 As shown, the dual-polarized array antenna in this embodiment adopts a 2×2 array structure, including four dual-polarized antenna elements. Each dual-polarized antenna element has two orthogonal polarization ports, which are used for feeding radio frequency signals in the first polarization direction and the second polarization direction, respectively. By periodically arranging the four dual-polarized antenna elements, a dual-polarized array antenna with eight radio frequency ports can be formed.

[0042] In this example, the four antenna elements of the 2×2 array antenna are arranged in a rectangular array, with a preset element spacing between adjacent antenna elements. The element spacing can be set according to the operating frequency band, beam scanning range, and array size requirements. Preferably, the array antenna can operate in two frequency bands near the Ku band, where the first operating frequency band corresponds to the first polarization port group, and the second operating frequency band corresponds to the second polarization port group. It should be noted that the operating frequency band and array spacing are only one preferred embodiment, and those skilled in the art can adjust them according to actual application requirements.

[0043] Each dual-polarized antenna element employs a multi-layer coupled feed structure. From top to bottom, the antenna element includes an upper dielectric substrate, a radiating patch, a first air layer, a slotted ground plane, a lower feed dielectric substrate, a microstrip feed layer, a second air layer, and a reflector. The upper dielectric substrate supports and fixes the radiating patch; the radiating patch forms the main radiating structure; the first air layer, located between the radiating patch and the slotted ground plane, adjusts the antenna's resonant characteristics and radiation performance; the slotted ground plane enables electromagnetic coupling between the microstrip feed and the radiating patch; the lower feed dielectric substrate carries the microstrip feed; the second air layer is positioned between the microstrip feed layer and the reflector; and the reflector improves the antenna's unidirectional radiation characteristics and enhances the array antenna's forward radiation capability.

[0044] The radiating patch is disposed on the lower surface of the upper dielectric substrate. In this example, each antenna element corresponds to one radiating patch, and the four radiating patches are arranged in a 2×2 array. The radiating patch can be a square patch, a rectangular patch, or other metal patch structure suitable for dual-polarization operation. Preferably, this embodiment uses a square radiating patch to facilitate symmetrical structural arrangement and dual-polarization operation.

[0045] The slotted ground plane is positioned below the radiating patches and corresponds to the location of each radiating patch. A set of coupling slots is provided below each radiating patch, and each set includes two mutually perpendicular and staggered H-shaped coupling slots. The two H-shaped coupling slots correspond to two orthogonal polarization directions, and they do not intersect. By arranging the two H-shaped coupling slots within the coverage area of ​​the radiating patches, two orthogonal polarization feed channels can be coupled to the same radiating patch through their corresponding coupling slots, thereby achieving dual-polarization operation.

[0046] In this example, one H-shaped coupling slot in each set of coupling slots is arranged along a first direction to correspond to the first polarization port; the other H-shaped coupling slot is arranged along a second direction perpendicular to the first direction to correspond to the second polarization port. The two H-shaped coupling slots are staggered within the same radiating patch coverage area, allowing them to couple to their respective microstrip feed lines while reducing mutual interference between the two polarization channels. By adjusting the length, width, slot spacing, and relative position of the H-shaped coupling slots, the impedance matching characteristics, resonant frequency, and port isolation performance of the antenna element can be adjusted.

[0047] The microstrip feed layer is located on the lower surface of the lower feed dielectric substrate or on one side close to the lower feed dielectric substrate. Each antenna element corresponds to two microstrip feed lines, which respectively mate with two corresponding H-shaped coupling slots. Each microstrip feed line is introduced from the edge of the array antenna or the feed port and extends to the vicinity of the middle region of the corresponding H-shaped coupling slot, thereby forming a coupled feed with the radiating patch through the slotted ground plane. The microstrip feed lines are arranged independently and do not cross each other to reduce the mutual coupling between the feed networks and the manufacturing complexity.

[0048] In this example, the first polarization port group of the array antenna includes ports P1, P3, P5, and P7, and the second polarization port group includes ports P2, P4, P6, and P8. The first and second polarization port groups correspond to different polarization feed channels in the four array elements, respectively. By grouping the ports according to polarization and operating frequency band, it is easier to connect and control the subsequent power divider feed network, RF switch module, and FPGA control module.

[0049] To facilitate actual fabrication and testing, the array antenna can also be equipped with multiple SMA RF interfaces and mounting holes. The SMA RF interfaces connect to corresponding microstrip feed lines, enabling connection between external RF circuitry and the array antenna ports. Mounting holes are located at the edge of the array antenna substrate or reflector to secure the upper dielectric substrate, slotted ground plane, lower feed dielectric substrate, and reflector, thereby ensuring the relative stability of each layer. The inclusion of air gaps and reflectors further enhances the stability and ease of testing of the array antenna structure.

[0050] like Figure 4 As shown, the power divider feed network in this embodiment includes a first polarization or first frequency band power divider feed network and a second polarization or second frequency band power divider feed network. The first polarization or first frequency band power divider feed network is used to provide RF excitation to the first polarization port group, and the second polarization or second frequency band power divider feed network is used to provide RF excitation to the second polarization port group.

[0051] In this example, the first polarization or first frequency band power divider feed network includes a first 1×4 power divider, and the second polarization or second frequency band power divider feed network includes a second 1×4 power divider. The input of the first 1×4 power divider is connected to the first frequency band RF signal source, and its output forms four RF output signals. The input of the second 1×4 power divider is connected to the second frequency band RF signal source, and its output forms four RF output signals. By powering the two sets of polarization ports with two power dividers respectively, the signal paths between the two sets of ports can be made independent, facilitating separate control of the array operation modes under different frequency bands or polarization states.

[0052] The RF switch module is positioned between the power divider feed network and the array antenna port. The RF switch module includes multiple RF switches; in this example, it includes RF switches 1 to RF switches 8. The RF input terminal of each RF switch is connected to the output terminal of the corresponding power divider, the RF output terminal of each RF switch is connected to the corresponding RF port of the array antenna, and the control terminal of each RF switch is connected to the FPGA control module.

[0053] Specifically, the four output terminals of the first 1×4 power divider are connected to RF switches 1, 3, 5, and 7, respectively. The RF output terminals of RF switches 1, 3, 5, and 7 are connected to the first polarization port group P1, P3, P5, and P7 of the array antenna, respectively. The four output terminals of the second 1×4 power divider are connected to RF switches 2, 4, 6, and 8, respectively. The RF output terminals of RF switches 2, 4, 6, and 8 are connected to the second polarization port group P2, P4, P6, and P8 of the array antenna, respectively.

[0054] In another embodiment, the RF switches and ports can be connected according to the array element positions, that is, each dual-polarized antenna element corresponds to two RF switches, one of which is connected to the first polarization port of the element, and the other is connected to the second polarization port of the element. Regardless of whether the connection method is grouped by polarization or by array element position, as long as a one-to-one correspondence between the power divider output, the RF switches, and the array ports can be achieved, it falls within the scope of this invention.

[0055] Each RF switch includes at least an RF input terminal, an RF output terminal, and a control terminal. The RF input terminal receives RF signals from the power divider feed network, the RF output terminal outputs RF signals to the corresponding array port, and the control terminal receives switch control signals from the FPGA control module. When the RF switch is in the ON state, the RF signal of the corresponding power divider branch is transmitted to the corresponding array port; when the RF switch is in the OFF state, the corresponding array port does not participate in the radiation at the current moment, or the branch signal is absorbed by a matched load to reduce port reflection and inter-channel interference.

[0056] The FPGA control module is connected to the control terminal of each RF switch and is used to output independent control signals or group control signals to each RF switch. Each RF switch is positioned between the output branch of the power divider network and the array antenna port. Therefore, the FPGA control module can change the connection between the power divider network and the array port by controlling the on / off states of different RF switches. Specifically, under different operating frequency bands, the FPGA control module keeps the RF switch branch corresponding to the current operating frequency band in a controllable on state and keeps the RF switch branch corresponding to the non-operating frequency band in an off or isolated state. Under different polarization modes, the FPGA control module enables the corresponding polarization port group to participate in the feeding, and performs timing control on one or two polarization port groups according to the single-polarization or dual-polarization operating mode. In beam switching or beam scanning mode, the FPGA control module loads preset timing parameters into the corresponding RF switch control channel, causing the array port participating in the operation to connect to the power divider network according to the preset timing. Thus, the power divider network is no longer used merely as a passive network for fixed RF signal distribution, but together with the RF switch module and the FPGA control module, it constitutes a reconfigurable time-modulated feed network. This network can dynamically change the port groups involved in feeding, the conduction sequence of each branch, and the excitation state of each array port according to the operating frequency band, polarization mode, and target beam state, thereby providing a switchable and programmable feeding basis for pattern control of dual-polarized array antennas.

[0057] In actual testing or prototype implementation, the RF signal source can be a vector network analyzer, signal generator, or other microwave signal generating equipment; the power divider feed network can be an external 1×4 power divider or a microstrip power divider network integrated with the system; the RF switch module can be an integrated RF switch chip, an RF switch evaluation board, or a standalone RF switch circuit; the FPGA control module can be connected to the RF switch control terminal via pin headers, coaxial control lines, DuPont wires, or dedicated connectors. A DC power supply is used to provide the required operating voltage for the RF switch module and the FPGA control module; if necessary, level conversion, power filtering, and isolation protection circuits can be added to the RF switch control terminal.

[0058] Through the above connection method, this invention can allocate radio frequency signals of different frequency bands and polarizations to the corresponding array ports, and control the working state of the radio frequency switches through FPGA to achieve timing excitation control of the eight radio frequency ports of the 2×2 dual-polarized array antenna. This connection structure has the advantages of clear port correspondence, high modularity, and ease of processing, debugging, and subsequent expansion.

[0059] like Figure 5As shown, in this embodiment, the FPGA control module generates multiple periodic time-modulated control signals and outputs them to the control terminals of each RF switch in the RF switch module. By controlling the on-state, off-state, on-start time, and on-duration of each RF switch within a time modulation period, the equivalent excitation state of each RF port of the array antenna at different times can be changed, thereby achieving the control of the array pattern and beam pointing. Within one time modulation period T, only one RF switch is in the on-state; the FPGA outputs a periodic gating signal sequence S1-S2-S3-S4-...; through cyclic switching, the time-division activation and beam pointing control of the eight RF ports are achieved.

[0060] In this example, FPGA The control module generates corresponding control signals based on the beam pointing parameters, operating frequency band parameters, polarization selection parameters, and timing parameters sent by the host computer or control computer. These control signals can be square wave signals, pulse signals, or other periodic digital control signals. Each control signal corresponds to an RF switch, which is turned on or off according to the high or low level state of the corresponding control signal.

[0061] To describe the operating state of an RF switch, the first... The switching state function of each RF switch is: , indicating the first Each radio frequency switch is always in the ON state; , indicating the first A radio frequency switch at time It is in the off state.

[0062] in, =1,2,…,8, when At that time, the radio frequency signal of the corresponding branch in the power divider network passes through the first... Each RF switch transmits data to the corresponding array antenna port; when At that time, the corresponding array antenna port does not participate in the radiation at the current moment, or is in a matched absorption state.

[0063] Furthermore, the first The switching function of the RF switch within one time modulation period can be expressed as:

[0064] , In the formula, Indicates the first RF switch in Constant work status; This indicates that the RF switch is in the ON state, and the RF signal of the corresponding branch in the power divider feed network can be transmitted to the corresponding port of the array antenna; This indicates that the RF switch is in the off state, and the corresponding array port does not participate in radiation at the current moment or is in an isolated state. This indicates the... The on-start time of the RF switch within one modulation cycle. Indicates the duration of conduction.

[0065] Within a time modulation period T, the conduction time periods of different RF switches can be set. For example, in the first time period, the first RF switch is turned on, activating the P1 port of the first antenna element; in the second time period, the second RF switch is turned on, activating the P3 port of the second antenna element; in the third time period, the third RF switch is turned on, activating the P5 port of the third antenna element; and in the fourth time period, the fourth RF switch is turned on, activating the P7 port of the fourth antenna element. A similar method can be used for the second polarization port group, controlling the fifth, sixth, seventh, and eighth RF switches sequentially or according to a preset rule, so that the corresponding P2, P4, P6, and P8 ports are activated according to a preset timing sequence.

[0066] In this example, the first polarization port group P1, P3, P5, and P7 correspond to the first operating frequency band, and the second polarization port group P2, P4, P6, and P8 correspond to the second operating frequency band. The FPGA control module can output valid control signals only to the RF switches of the corresponding port group based on the currently selected operating frequency band and polarization mode, or it can simultaneously control both groups of ports. By changing the conduction sequence and conduction time of the RF switches corresponding to different ports, the array can form different equivalent excitation distributions at different times.

[0067] In another embodiment, the conduction duration and conduction start time of each RF switch are set according to different beam control conditions: When the array needs to form a beam scanning state with equal amplitude excitation, the conduction duration of each RF switch is set to be the same, so that each array port has the same or approximately the same duty cycle within one time modulation period; at the same time, the conduction start time of each control signal is set according to the target beam direction, so that a relative delay relationship corresponding to the target beam direction is formed between adjacent array ports, thereby obtaining the required equivalent phase difference. When the array needs to perform sidelobe suppression, main lobe width adjustment, or pattern amplitude weighting, the conduction duration of each RF switch is set to be different, so that different array ports have different duty cycles, thereby forming a preset equivalent amplitude distribution; at the same time, the conduction start time of each control signal is still set according to the phase relationship corresponding to the target beam direction, so as to ensure that the main beam direction of the array meets the preset requirements. When the array needs to form a normal beam, the on-start time of each control signal can be set to be the same, or set to a timing relationship that makes the equivalent phase difference between each array port zero. When the array needs to form a deflection beam, the on-start time of each control signal increases or decreases sequentially according to the array port arrangement order, so that a preset relative delay is formed between adjacent ports. The relative delay can be calculated based on the target beam direction, array element spacing, current operating wavelength, and preset phase relationship, or it can be obtained through simulation optimization or a pre-calibrated timing parameter table. Therefore, this implementation method does not simply perform fixed-period on / off control of the RF switch, but sets the conduction duration, duty cycle, conduction start time and relative delay for different operating conditions such as normal beam, deflection beam and pattern amplitude weighting, so that each port of the array forms an equivalent amplitude and equivalent phase distribution corresponding to the target beam pattern within the time modulation period.

[0068] Specifically, if each array port has a different turn-on start time within a time modulation period, the RF signals corresponding to different ports will form different equivalent amplitude and phase distributions in a time-averaged sense. Because the first... Switching function of RF switch Since it is a periodic function, it can be expanded using Fourier transform. In the formula, m represents the order of the sideband, m = 0, ±1, ±2, ...; Indicates the time modulation frequency; This represents the Fourier coefficient of the nth RF switch in the m-th sideband. This coefficient is a complex number containing amplitude and phase information, and therefore can be used to characterize the equivalent excitation state of the nth array port in different sidebands. The first-order frequency component can be expressed as: In the formula, The carrier frequency output by the radio frequency signal source. The modulation frequency is used by the FPGA to control the periodic on and off of the RF switch, where m is the sideband order. When m=0, it corresponds to the original carrier. When m=1, it corresponds to a positive first-order sideband. When m=-1, it corresponds to the negative first-order sideband. Therefore, it can be seen that the periodic switching on and off of the radio frequency switch will cause the original carrier signal to generate sideband components in the frequency domain, which is the frequency domain manifestation of time modulation.

[0069] , In the formula, This represents the equivalent phase difference between adjacent ports on the m-th sideband; m represents the sideband order. This indicates the conduction start time difference between two adjacent RF switch control signals; T represents the time modulation period.

[0070] As shown in the above equation, given a fixed time modulation period T, changing the relative delay between the control signals of each RF switch can achieve the desired effect. This allows the equivalent phase difference between the array ports on the target sideband to be changed. Once a preset equivalent phase difference is formed between the array ports, this equivalent phase difference acts on the array pattern synthesis process, causing changes in the main lobe direction, sidelobe distribution, or beamwidth. Therefore, this invention can achieve array beam direction control without using traditional phase shifters by outputting periodic control signals with different relative delays through an FPGA.

[0071] This equivalent amplitude and phase distribution, applied to a 2×2 dual-polarized array antenna, can alter the main lobe direction, sidelobe distribution, or polarization state of the array pattern. Therefore, this invention eliminates the need for a separate traditional phase shifter in each array channel; array beam control can be achieved through RF switches and FPGA timing control.

[0072] In this embodiment, the FPGA control module can also be configured with a clock or synchronization signal input. The clock or synchronization signal input provides a unified clock reference for each time modulation control signal, thereby ensuring the stability of the relative delay and timing relationship between multiple control signals. By modifying the timing parameters inside the FPGA via a host computer or control computer, switching between different beam directions, different frequency bands, and different polarization states can be achieved.

[0073] To verify the feasibility of the dual-polarized time-modulated array antenna system described in this invention, electromagnetic simulation software can be used to model the dual-polarized array antenna and perform simulation analysis on its port reflection coefficient, port isolation, and radiation pattern.

[0074] like Figure 6 As shown, in this example, the array antenna can form an effective resonant response within the operating frequency band. This operating frequency band corresponds to polarization port groups P1, P3, P5, and P7. By adjusting the size of the radiating patch, the size of the H-type coupling slot, the position of the microstrip feed line, the air layer thickness, and the reflector spacing, the array antenna can achieve a better impedance matching effect near the target frequency band.

[0075] like Figure 7 As shown, at the 16.5 GHz operating frequency, the radiation pattern of the array antenna changes significantly after applying different equivalent phase excitations or setting different RF switch timing parameters to the array port group. Figure 7The paper presents radiation pattern results under three different control states. Each group includes far-field radiation pattern results obtained from electromagnetic simulation software and normalized radiation pattern results obtained from angle-level data processing. The results show that when the equivalent excitation state between array ports changes, the array main lobe direction, main lobe width, side lobe distribution, and peak voltage average change accordingly. This demonstrates that the port grouping control and RF switch timing control methods described in this invention can effectively regulate the array radiation state.

[0076] In the first set of control states, a preset equivalent phase relationship is applied to the corresponding ports in the first polarization port group, and the array pattern forms a deflected main lobe at 16.5 GHz. Figure 7 (a) It can be seen that in this state, the main lobe direction is approximately 14.0°, the main lobe gain is approximately 13.1 dBi, the 3 dB beamwidth is approximately 44.1°, and the sidelobe level is approximately -9.7 dB. The corresponding normalized radiation pattern further shows that the main lobe region is relatively concentrated, and the main lobe direction is basically consistent with the preset deflection direction. However, some sidelobes and test fluctuations still exist in non-main lobe directions. This result indicates that when a suitable equivalent phase difference is formed between the array ports, the array can form a deflection beam near the predetermined direction.

[0077] In the second set of control states, the array ports use a different set of equivalent phase or timing parameter settings. Figure 7 (b) shows that the main lobe direction of the array at 16.5 GHz is approximately 13.0°, the main lobe gain is approximately 13.4 dBi, the 3 dB beamwidth is approximately 39.6°, and the sidelobe level is approximately -7.8 dB. Compared with the first set of control states, the main lobe direction remains around 13° in this state, indicating that the array can maintain a similar beam deflection direction under different control parameters. Meanwhile, the main lobe width and sidelobe level change, indicating that the equivalent excitation distribution at the ports affects not only the main lobe pointing direction but also the main lobe width and sidelobe distribution of the radiation pattern. The normalized radiation pattern shows that the main lobe is more pronounced in this control state, and there are certain fluctuations in the radiation pattern, which is consistent with the non-ideal characteristics that may occur during actual array port synthesis and subsequent testing.

[0078] In the third set of control states, the equivalent excitation state of the array ports changes further. Figure 7(c) It can be seen that in this state, the main lobe direction of the array is approximately 15.0°, but the main lobe peak level is approximately -9.03 dBi, the 3 dB beamwidth is approximately 18.4°, and the sidelobe level is approximately -1.8 dB. This result indicates that under these control parameters, although the array can still achieve a certain direction of main lobe deflection, the main lobe level is significantly reduced, while the sidelobe level is higher, resulting in decreased differentiation between the main lobe and sidelobe. This state suggests that when the equivalent phase or amplitude distribution of the ports is not set appropriately, beam deflection may still occur, but the pattern quality will decrease, manifested as a reduction in peak level, increased sidelobe height, and dispersed radiated energy. Therefore, in practical time modulation control, it is necessary to comprehensively optimize the turn-on start time, turn-on duration, duty cycle, and relative delay of each RF switch by considering the target beam pointing, sidelobe suppression requirements, and channel amplitude-phase consistency.

[0079] The comparison of the three sets of radiation patterns above shows that, at the same operating frequency, the main lobe direction and radiation state of the array antenna can be controllably changed by altering the equivalent phase relationship of the ports or the control timing parameters. The results of the first and second sets indicate that the array can form a relatively significant deflected main lobe in the approximately 13°–14° direction; the results of the third set show that different control parameters significantly affect the main lobe level and sidelobe level. These comparative results demonstrate that the present invention does not merely achieve static radiation through a fixed power divider network, but rather can change the equivalent excitation state of the array ports through the RF switching module and the FPGA timing control module, thereby achieving the control of the array beam direction or radiation state.

[0080] Furthermore, during actual time modulation, the equivalent phase difference between each array port can be generated by the conduction start time difference or relative delay between different RF switch control signals, and the equivalent amplitude of each array port can be adjusted by the conduction duration or duty cycle of the corresponding control signal. Therefore, Figure 7 The changes in the radiation pattern under different control states shown can be used to illustrate that after the "power divider feed network—RF switch module—FPGA control module—dual-polarized array antenna" of this invention work together, different port equivalent amplitude and phase distributions can be formed, and the main lobe pointing, main lobe width, and side lobe distribution of the array can be further changed. This result verifies the feasibility of the dual-polarized time modulation array antenna system proposed in this invention in terms of beam control.

[0081] In this example, the FPGA control module controls the RF switch module by outputting periodic control signals, thereby activating different RF ports of the array antenna at different times. For the first polarization port group, the equivalent excitation states of ports P1, P3, P5, and P7 can be adjusted by controlling the first to fourth RF switches, respectively; for the second polarization port group, the equivalent excitation states of ports P2, P4, P6, and P8 can be adjusted by controlling the fifth to eighth RF switches, respectively. Thus, the equivalent amplitude and phase distribution of the array can be adjusted through switching timing control without using a traditional phase shifter.

Claims

1. A time-modulated dual-polarized array antenna system, comprising a dual-polarized array antenna, a radio frequency signal source, and a power divider feed network, wherein the dual-polarized array antenna comprises multiple dual-polarized antenna elements, characterized in that, It also includes an RF switch module and an FPGA control module. The RF switch module contains multiple RF switches, which group the ports of the dual-polarized array antenna according to the operating frequency band and polarization mode. Each port group corresponds one-to-one with the corresponding power divider in the power divider feed network, the corresponding RF switch in the RF switch module, and the corresponding control signal output by the FPGA control module. Specifically, two or more ports of the dual-polarized array antenna in the same polarization direction or the same operating frequency band constitute a port group. Each port group is provided with RF signals by the corresponding power divider and connected to each array port through the corresponding RF switch. The FPGA control module outputs valid timing control signals only to the port groups that are participating in the operation, or outputs different timing control signals to different port groups, depending on the currently selected operating frequency band and polarization state.

2. The time-modulated dual-polarized array antenna system according to claim 1, characterized in that, The RF signal source inputs the RF signal to the power divider network. After power distribution processing by the power divider network, the signal is sent to the RF switch module. The RF switch module, equipped with multiple RF switches, sends the signal to the dual-polarized array antenna after controlled feeding processing. An FPGA control module is also provided. The FPGA control module outputs multiple periodic digital control signals to the RF switch module. Each periodic digital control signal controls the on and off states of one RF switch. By setting the modulation period, on start time, on duration, and duty cycle parameters, multiple synchronization control signals are output to enable each port of the array antenna to form a preset equivalent amplitude and phase distribution within the time modulation period to achieve the target beam pattern.

3. The time-modulated dual-polarized array antenna system according to claim 1, characterized in that, The periodic digital control signal output by the FPGA module is a rectangular pulse signal or a square wave signal, and its parameters include the modulation period. , conduction start time Conduction duration Duty cycle and relative delay ,in Indicates the first RF switch, in one modulation cycle within, when When the path control signal is high, the corresponding RF switch is turned on, and the RF signal of the corresponding branch in the power divider feed network is transmitted to the corresponding port of the array antenna; when the first... When the circuit control signal is low, the corresponding RF switch is off, and this port does not participate in radiation at the current moment or is in a matched absorption state. Let the modulation period of the periodic control signal output by the FPGA control module be... The corresponding modulation frequency It can be represented as: The duty cycle satisfy Used to regulate the first The equivalent excitation amplitude of each array port; the conduction start time or the relative delay between each control signal. Used to adjust the first The equivalent excitation phase of each array port.

4. The time-modulated dual-polarized array antenna system according to claim 1, characterized in that, In a power divider feeder network, the power divider is configured as either 1 to 4 or 1 to 2, corresponding to dual-frequency operation, to ensure uniform distribution and amplitude matching of dual-frequency signals. The output of the power divider is electrically connected to an RF switch to distribute individual signals to each antenna port in groups.

5. The time-modulated dual-polarized array antenna system according to claim 1, characterized in that, The radio frequency switch module includes 2N radio frequency switches, where N is the number of antenna elements in the dual-polarized array antenna. The 2N radio frequency switches are connected to the antenna elements in pairs. Taking eight radio frequency switches as an example, the output terminal of the first radio frequency switch is connected to the first antenna element P1, the output terminal of the second radio frequency switch is connected to the second antenna element P3, the output terminal of the third radio frequency switch is connected to the third antenna element P5, the output terminal of the fourth radio frequency switch is connected to the fourth antenna element P7, the output terminal of the fifth radio frequency switch is connected to the first antenna element P2, the output terminal of the sixth radio frequency switch is connected to the second antenna element P4, the output terminal of the seventh radio frequency switch is connected to the third antenna element P6, and the output terminal of the eighth radio frequency switch is connected to the fourth antenna element P8.

6. The time-modulated dual-polarized array antenna system according to claim 1, characterized in that, The dual-polarized array antenna includes at least one dual-polarized antenna element. Each element comprises a stacked structure: an upper radiating patch, an air layer, a slotted ground plane, a feed dielectric board, a feed line, and a lower reflector. Below the radiating patch are two vertical H-shaped slots, and the feed line is electrically connected to the feed board through the slots. Multiple antenna elements are arranged in a 2×2 array, and the ports of each element are numbered P1-P8. The antenna element feed line is a straight microstrip line of equal width, and is arranged perpendicular to the corresponding slot. The feed line length is optimized so that the upper radiating patch completely covers the slot.

7. A beam control method for a time-modulated dual-polarized array antenna system as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Select the corresponding array port group based on the signal operating frequency band and polarization. Based on the current operating frequency band and polarization state, select the port group to participate in the operation from multiple RF ports of the dual-polarized array antenna. Different polarization port groups correspond to different polarization radiation states, and different operating frequency bands correspond to corresponding feed ports or feed branches. Step 2: Determine the target beam pointing or target pattern requirements, and based on the array element positions, operating wavelength, and target beam pointing, determine the equivalent excitation amplitude and equivalent excitation phase required for each array port. For the first... Each array port has an equivalent excitation amplitude denoted as and an equivalent excitation phase denoted as . ; Step 3: Convert the required equivalent phase difference of each port into the conduction start time difference of the corresponding RF switch control signal; simultaneously, set the conduction duration or duty cycle of each control signal according to the amplitude weighting requirements of the target pattern, and generate periodic control signals corresponding to each array port by the FPGA control module. The periodic control signals are rectangular pulse signals or square wave control signals, and each periodic control signal controls the conduction and cutoff of one RF switch; the parameters of the periodic control signal include the time modulation period. , conduction start time Conduction duration Duty cycle and relative delay ,in Indicates the first Each channel has a radio frequency switch with a duty cycle, and each channel's periodic control signal has a unified clock reference and can be independently configured according to a preset beam direction. Step 4: Based on the preset beam pointing or pattern requirements, set the timing parameters of each periodic control signal according to the preset mapping rules: First, determine the equivalent excitation phase required for each array port based on the target beam pointing, array unit position, and wavelength corresponding to the current operating frequency band; then, determine the equivalent excitation amplitude required for each array port based on the amplitude weighting requirements of the target pattern. For the i-th array port, convert its required equivalent excitation phase into the conduction start time of the corresponding control signal. or relative delay The required equivalent excitation amplitude is converted into the conduction duration of the corresponding control signal. or duty cycle When the target beam direction changes, the FPGA control module recalculates or calls the pre-stored timing parameter table according to the new target beam direction, and updates the conduction start time of each control signal. or relative delay This changes the equivalent phase difference between array ports; when the sidelobe level, main lobe width, or amplitude weighting requirement of the target pattern changes, the FPGA control module updates the conduction duration of each control signal. or duty cycle This is done to change the equivalent amplitude distribution between array ports, thereby enabling the selected array port group to form an equivalent amplitude and phase distribution corresponding to the target beam pattern within one time modulation period; Step 5: The radio frequency signal is distributed to multiple branches through the power divider network and connected to the selected array port group through the radio frequency switch module. Under the action of the FPGA control signal, the radio frequency switch module is turned on or off according to the preset timing, so that each array port obtains the corresponding equivalent excitation amplitude and equivalent excitation phase within a time modulation period, thereby enabling the array to form the target beam pattern in the corresponding operating frequency band and polarization state.

8. The beam control method for a time-modulated dual-polarized array antenna system according to claim 7, characterized in that, In step four, the conduction duration and conduction start time of each RF switch are set according to different beam control conditions: When the array needs to form a beam scanning state with equal amplitude excitation, the conduction duration of each RF switch is set to be the same, so that each array port has the same or approximately the same duty cycle within one time modulation period; at the same time, the conduction start time of each control signal is set according to the target beam direction, so that a relative delay relationship corresponding to the target beam direction is formed between adjacent array ports, thereby obtaining the required equivalent phase difference. When the array needs to perform sidelobe suppression, main lobe width adjustment, or pattern amplitude weighting, the conduction duration of each RF switch is set to be different, so that different array ports have different duty cycles, thereby forming a preset equivalent amplitude distribution; at the same time, the conduction start time of each control signal is still set according to the phase relationship corresponding to the target beam direction, so as to ensure that the main beam direction of the array meets the preset requirements. When the array needs to form a normal beam, the on-start time of each control signal can be set to be the same, or set to a timing relationship that makes the equivalent phase difference between each array port zero; when the array needs to form a deflection beam, the on-start time of each control signal increases or decreases sequentially according to the array port arrangement order, so that a preset relative delay is formed between adjacent ports; the relative delay can be calculated based on the target beam direction, array unit spacing, current operating wavelength and preset phase relationship, or obtained through simulation optimization or a pre-calibrated timing parameter table.

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