An array antenna protection system and method based on energy-selective phase shifters

Abstract

The application discloses an array antenna protection system and method based on energy selection phase shifters, which comprises an array antenna, a power distributor and a plurality of energy selection phase shifters; the input end of each energy selection phase shifter is connected with the antenna unit through an array element feeding network, the output end of each energy selection phase shifter is connected with the power distributor, the output end of the power distributor is used for outputting signals to the transceiving device at the back end; the energy selection phase shifter is used for adjusting the phase of signals greater than a threshold power level, and the power distributor is responsible for integrating and canceling the high-power signals which are phase shifted; the energy selection phase shifter is divided into energy selection phase shifter A and energy selection phase shifter B; and the energy selection phase shifters are alternately arranged as energy selection phase shifter A and energy selection phase shifter B. The application can prevent high-power signals from affecting the sensitive transceiving device at the back end, and the protection capability can be improved with the expansion of the array scale.

Description

Technical Field

[0001] This invention relates to the field of strong electromagnetic protection, and in particular to an array antenna protection system and method based on an energy selective phase shifter. Background Technology

[0002] Phased array antennas combine high gain and beam reconfigurability, achieving beam agility through control of the phase of the array element feed. This ability to achieve rapid beam scanning without physical movement makes them widely used in communications, tracking, telemetry, and control. However, phased array antenna systems integrate numerous highly sensitive precision electronic components, resulting in high manufacturing costs. The high gain and sensitivity of phased array antenna systems also make them more vulnerable to damage from strong electromagnetic threats such as high-power microwaves. The economic losses from the destruction of high-value phased array antenna systems under strong electromagnetic attacks are unbearable. Therefore, implementing strong electromagnetic protection measures for phased array antenna systems is of paramount importance.

[0003] As frequency-using devices, phased array antenna systems cannot be protected by shielding, filtering, or absorption. Current mainstream protection measures focus on filtering the signal amplitude (the power contained in the signal), including power limiters, energy-selective surfaces, and energy-selective antennas. These measures can adaptively enter a high-isolation protection mode under the influence of power signals, preventing harmful signals from entering subsequent circuits. These methods primarily limit the signal amplitude. Although larger arrays use more semiconductor devices, the protection level of current methods does not increase with the size of the array. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an array antenna protection system and method based on an energy selective phase shifter. The energy selective phase shifter is responsible for adjusting the phase of signals with power levels greater than a threshold, and the power divider is responsible for integrating and canceling these phase-shifted high-power signals to prevent excessively high-power signals from entering sensitive transceiver equipment. Furthermore, the protection capability can be improved as the array size increases.

[0005] The objective of this invention is achieved through the following technical solution: an array antenna protection system based on energy selective phase shifters, comprising an array antenna, a power divider, and multiple energy selective phase shifters;

[0006] The input of each energy selective phase shifter is connected to the array antenna through an array element feed network, and the output of each energy selective phase shifter is connected to a power divider. The output of the power divider is used to output signals to the external device and transmit them to the back-end transceiver.

[0007] The energy selection phase shifter is used to adjust the phase of signals with power levels greater than the threshold, and the power divider is responsible for integrating and canceling these phase-shifted high-power signals.

[0008] The energy selective phase shifter is divided into two types: energy selective phase shifter A and energy selective phase shifter B. Energy selective phase shifter A provides a hysteretic additional phase shift value in protection mode, while energy selective phase shifter B provides a leading phase shift value in protection mode. The energy selective phase shifter is alternately set as energy selective phase shifter A and energy selective phase shifter B.

[0009] The power divider, also known as a power splitter, can also be used as a combiner, thus enabling the synthesis of the output signals of each energy selection phase shifter and the completion of integration and cancellation.

[0010] Preferably, the transceiver device is implemented using a transceiver chip, which is used to amplify, down-convert, and filter the signal output from the power divider, and then convert it into a digital baseband signal via an ADC.

[0011] The array antenna includes multiple antenna elements, and the number of antenna elements is the same as that of the energy selective phase shifters and they correspond one-to-one. Each energy selective phase shifter is connected to the corresponding antenna element through an array element feed network.

[0012] The array element feeding network includes an array element antenna balun structure and an electronic phase shifter connected in sequence. The balun structure is responsible for balancing the array element feeding, and the electronic phase shifter is used to realize the beam scanning capability of the array antenna.

[0013] The energy selective phase shifter A includes capacitors C1, C2, and C3, and inductors L1, L2, and L3. The first terminal of capacitor C1 serves as the input terminal of the energy selective phase shifter A. The second terminal of capacitor C1 is connected to the first terminal of capacitor C2 via inductors L1 and L2, and the second terminal of capacitor C2 serves as the output terminal of the energy selective phase shifter A. The first terminal of capacitor C3 is connected between inductors L1 and L2, and the second terminal of capacitor C3 is grounded via inductor L3. Two PIN diodes of opposite polarity are connected in parallel across the terminals of each of the first capacitor C1, second capacitor C2, and third inductor L3.

[0014] The energy selection phase shifter B includes capacitors, fourth inductor L4, fifth inductor L5, sixth inductor L6, seventh inductor L7, fourth capacitor C4, and fifth capacitor C5.

[0015] The first terminal of the fourth inductor L4 serves as the input terminal of the energy selection phase shifter B. The second terminal of the fourth inductor L4 is connected to the first terminal of the fifth inductor L5 in sequence through the fourth capacitor C4 and the fifth capacitor C5. The second terminal of the fifth inductor L5 serves as the output terminal of the energy selection phase shifter B. The first terminal of the sixth inductor L6 is connected between the fourth capacitor C4 and the fifth capacitor C5. The second terminal of the sixth inductor L6 is grounded through the seventh inductor L7. Two PIN diodes with opposite polarities are connected in parallel at both ends of the fourth inductor L4, the fifth inductor L5, and the seventh inductor L7.

[0016] A method for protecting an array antenna based on an energy selective phase shifter includes the following steps:

[0017] S1. In normal mode, the PIN diodes in both energy selection phase shifter A and energy selection phase shifter B are not conducting; the PIN diodes are treated as capacitors, and energy selection phase shifters A and B remain transparent, providing no phase shift value or signal attenuation.

[0018] S2. When a high-power microwave irradiates the array antenna protection system, if the high-power radio frequency signal coupled into the system from the array antenna causes the voltage across the PIN diode to exceed the conduction threshold, the PIN diode in the energy selection phase shifter A and energy selection phase shifter B will be adaptively activated to conduct, thereby enabling energy selection phase shifter A and energy selection phase shifter B to provide additional phase shift values, and causing the array antenna protection system to enter the adaptive protection mode.

[0019] In step S1, under normal mode, the PIN diodes in both energy-selective phase shifter A and energy-selective phase shifter B are not conducting; the PIN diodes are treated as capacitors. Energy-selective phase shifters A and B remain transparent, providing no phase shift value and signal attenuation. The principle behind this is as follows:

[0020] A1. In the energy selective phase shifter A, the first capacitor C1, two PIN diodes of opposite polarity connected in parallel across the first capacitor C1, and the first inductor L1 form a resonant structure, providing no additional phase shift in the transmission path; the second capacitor C2, two PIN diodes of opposite polarity connected in parallel across the second capacitor C2, and the second inductor L2 form a resonant structure, also providing no additional phase shift in the transmission path; the third inductor L3 and two PIN diodes of opposite polarity connected in parallel across the third inductor L3 block the grounding branch, making the branch invisible to the transmission path; therefore, the energy selective phase shifter A remains transparent, providing no phase shift value or signal attenuation;

[0021] A2. In the energy selective phase shifter B, the fourth inductor L4, the two PIN diodes with opposite polarities connected in parallel across the fourth inductor L4, and the fourth capacitor C4 form a resonant structure, providing no additional phase shift in the transmission path; the fifth inductor L5, the two PIN diodes with opposite polarities connected in parallel across the fifth inductor L5, and the fifth capacitor C5 form a resonant structure, also providing no additional phase shift in the transmission path; the seventh inductor L7, the two PIN diodes with opposite polarities connected in parallel across the seventh inductor L7 block the grounding branch, making the branch invisible to the transmission path; therefore, the energy selective phase shifter B remains transparent, providing no phase shift value or signal attenuation.

[0022] In step S2, when high-power microwaves irradiate the array antenna protection system, if the high-power radio frequency signal coupled into the system from the array antenna causes the voltage across the PIN diode to exceed the conduction threshold, the PIN diodes in energy selective phase shifters A and B are adaptively activated to conduct, thereby enabling energy selective phase shifters A and B to provide additional phase shift values. The principle behind this allows the array antenna protection system to enter the adaptive protection mode is as follows:

[0023] B1. When the PIN diode in energy selection phase shifter A is turned on:

[0024] Two PIN diodes of opposite polarity connected in parallel across the first capacitor C1 short-circuit the first capacitor C1; two PIN diodes of opposite polarity connected in parallel across the second capacitor C2 short-circuit the second capacitor C2; two PIN diodes of opposite polarity connected in parallel across the third inductor L3 short-circuit the third inductor L3.

[0025] At this point, the first inductor L1, the second inductor L2, and the third capacitor C3 form a T-type phase-shifting network, which plays a phase-shifting role;

[0026] B2. When the PIN diode of B in the energy selection phase shifter is turned on:

[0027] The two PIN diodes with opposite polarities connected in parallel across the fourth inductor L4 cause the fourth inductor L4 to short-circuit.

[0028] The two PIN diodes with opposite polarities connected in parallel across the fifth inductor L5 cause the fifth inductor L5 to short-circuit.

[0029] The two PIN diodes with opposite polarities connected in parallel across the seventh inductor L7 cause the seventh inductor L7 to short-circuit.

[0030] The fourth capacitor C4, the fifth capacitor C5, and the sixth inductor L6 form a T-type phase-shifting network, which plays a phase-shifting role.

[0031] B3. To ensure duality between energy-selective phase shifter A and energy-selective phase shifter B, let

[0032]

[0033] This results in energy selection phase shifter A and energy selection phase shifter B having opposite phase shift values ​​in protection mode;

[0034] B4. Since energy selective phase shifter A and energy selective phase shifter B are set alternately, when the signal from energy selective phase shifter A and the signal from energy selective phase shifter B enter the power divider for synthesis, the high-power signal that has been phase-shifted will be integrated and canceled, thereby preventing excessively high-power signals from entering the later-stage transceiver equipment.

[0035] The beneficial effects of this invention are: the present invention uses a selectable phase shifter to adjust the phase of signals with power levels greater than a threshold, and a power divider to integrate and cancel these phase-shifted high-power signals, preventing excessively high-power signals from entering sensitive transceiver equipment, and the protection capability can be improved as the array size increases. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall architecture of the present invention;

[0037] Figure 2 A schematic diagram of the equivalent circuit for energy selection phase shifter A;

[0038] Figure 3 A schematic diagram of the equivalent circuit for energy selection phase shifter B;

[0039] Figure 4 This is an exploded view of the prototype in the embodiment;

[0040] Figure 5 This is a schematic diagram of the power supply circuit in the embodiment;

[0041] Figure 6 This is a full-wave simulation result of the voltage standing wave ratio (VSWR) of the antenna subarray in normal mode in the embodiment.

[0042] Figure 7 This is a full-wave simulation result of the gain pattern of the antenna subarray in normal mode, as shown in the embodiment.

[0043] Figure 8 This is a full-wave simulation result of the gain pattern of the antenna subarray in protection mode in the embodiment.

[0044] Figure 9 The full-wave simulation results of the gain pattern of the antenna array in the embodiment are shown in normal mode (a) and protection mode (b).

[0045] Figure 10 This is a diagram showing the measured beam scanning capability of the entire antenna array in normal mode, as illustrated in the embodiment. Detailed Implementation

[0046] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0047] like Figure 1 As shown, an array antenna protection system based on energy selective phase shifters includes an array antenna, a power divider, a transceiver chip, and multiple energy selective phase shifters;

[0048] Figures 2-3 An equivalent circuit diagram of an energy selection phase shifter is given. Based on the phase shift value provided in the protection mode, the energy selection phase shifter can be divided into two types, A and B. Energy selection phase shifter A provides a lagging additional phase shift value in the protection mode, while energy selection phase shifter B provides a leading phase shift value in the protection mode.

[0049] The energy selective phase shifter A includes capacitors C1, C2, and C3, and inductors L1, L2, and L3. The first terminal of capacitor C1 serves as the input terminal of the energy selective phase shifter A. The second terminal of capacitor C1 is connected to the first terminal of capacitor C2 via inductors L1 and L2, and the second terminal of capacitor C2 serves as the output terminal of the energy selective phase shifter A. The first terminal of capacitor C3 is connected between inductors L1 and L2, and the second terminal of capacitor C3 is grounded via inductor L3. Two PIN diodes of opposite polarity are connected in parallel across the terminals of each of the first capacitor C1, second capacitor C2, and third inductor L3.

[0050] The energy selection phase shifter B includes capacitors, fourth inductor L4, fifth inductor L5, sixth inductor L6, seventh inductor L7, fourth capacitor C4, and fifth capacitor C5.

[0051] The first terminal of the fourth inductor L4 serves as the input terminal of the energy selection phase shifter B. The second terminal of the fourth inductor L4 is connected to the first terminal of the fifth inductor L5 in sequence through the fourth capacitor C4 and the fifth capacitor C5. The second terminal of the fifth inductor L5 serves as the output terminal of the energy selection phase shifter B. The first terminal of the sixth inductor L6 is connected between the fourth capacitor C4 and the fifth capacitor C5. The second terminal of the sixth inductor L6 is grounded through the seventh inductor L7. Two PIN diodes with opposite polarities are connected in parallel at both ends of the fourth inductor L4, the fifth inductor L5, and the seventh inductor L7.

[0052] For energy-selective phase shifter A, in protection mode, the PIN diode conducts, short-circuiting C1, C2, and L3. L1, L2, and C3 then perform the phase shifting function. Energy-selective phase shifter A is structurally symmetrical.

[0053]

[0054] Where x is the normalized impedance, b is the normalized admittance, and Z0 is the characteristic impedance of the system. After derivation, the phase shift value (in radians) provided by the energy selection phase shifter A in protection mode is:

[0055]

[0056] Furthermore, considering that the selectable phase shifter A needs to be matched with the system impedance Z0, there are constraints.

[0057]

[0058] Given the required phase shift value for the protection mode and the system impedance, a set of L1, L2, and C3 can be uniquely determined by equations (2) and (3).

[0059] In normal mode, the PIN diode is treated as a capacitor. The PIN diode, C1, and L1 form a resonant structure, ensuring that no additional phase shift is provided in the transmission path. Due to the symmetrical structure, the PIN diode, C2, and L2 also form a resonant structure. L3 and the PIN diode block the ground branch, making the ground branch invisible to the transmission path.

[0060] For energy-selective phase shifter B, in protection mode, the PIN diode conducts, shorting L4, L5, and L7. C4, C5, and L6 then perform phase shifting. Energy-selective phase shifter B is structurally symmetrical.

[0061]

[0062] Where x' is the normalized impedance, b' is the normalized admittance, and Z0 is the characteristic impedance of the system. After derivation, the phase shift value (in radians) provided by the energy selection phase shifter A in protection mode is:

[0063]

[0064] Similarly, there are matching condition constraints, namely...

[0065]

[0066] Given the required phase shift value for the protection mode and the system impedance, a set of C4, C5, and L6 can be uniquely determined by equations (7) and (8).

[0067] In normal mode, the PIN diode is treated as a capacitor. The PIN diode, L4, and C4 form a resonant structure, ensuring no additional phase shift is provided in the transmission path. Due to the symmetrical structure, the PIN diode, L5, and C5 also form a resonant structure. For the same PIN diode, the value of L3 is equal to that of L7.

[0068] There is duality between selectable phase shifter A and selectable phase shifter B. After completing the design of selectable phase shifter A, let...

[0069]

[0070] A selectable phase shifter B with opposite phase shift values ​​in protection mode can be obtained immediately.

[0071] The energy-selective phase shifter operates in two modes: normal mode and protection mode. In normal mode, the PIN diode is not conducting, forming a resonant structure with the LC element, keeping the energy-selective phase shifter transparent and providing no phase shift or signal attenuation. In protection mode, the PIN diode short-circuits some peripheral components, allowing the T-type phase shift network to be visible and providing additional phase shift. The switching between the two modes is adaptive, requiring no bias or control circuitry, and has sufficient response speed to ensure protection is implemented before the power signal damages subsequent circuitry.

[0072] This selectable phase shifter can be implemented in various ways, including but not limited to surface mount technology, printed circuit board technology, hybrid integrated substrate technology, and H-cub technology.

[0073] The feed network includes the necessary array element antenna balun structures and electronic phase shifters. The baluns balance the array element feeds, while the electronic phase shifters enable beam scanning of the array antenna. Selective phase shifters adjust the phase of signals exceeding a threshold power level, and power dividers integrate and cancel these phase-shifted high-power signals. This prevents excessively high-power signals from entering sensitive devices such as transceiver chips.

[0074] An array antenna equipped with an energy-selective phase shifter is given the ability to selectively beamform. The beam of the array antenna will adaptively diverge under the irradiation of high-power microwaves, thereby reducing the overall gain of the entire array antenna.

[0075] Energy-selective phase shifters are key to achieving energy-selective beamforming. Typically, the total gain of an array antenna is equal to the sum of the element antennas multiplied by the array factor.

[0076] G total (φ,θ)=G e (φ,θ)·AF(φ,θ) (8)

[0077] Where φ is the azimuth angle and θ is the elevation angle. For a two-dimensional uniform planar array, its array factor can be expressed as:

[0078]

[0079] M is the number of array elements in the x-direction, N is the number of array elements in the y-direction, and A is the number of array elements in the x-direction. k Let (x) be the complex voltage of the k-th antenna element. k ,y k () represents the spatial coordinates of the k-th element antenna. The complex voltage can be further written in terms of magnitude and phase.

[0080]

[0081] Array element feed phase α k In normal mode, θ is controlled by an electronic phase shifter. k With φ k Maintain consistency in the feeding structure of all array elements to achieve (φ k ,θ k The direction is the beam direction of the array antenna. In protection mode, the element feed phase α k It exists in a chaotic state to achieve a matrix factor without obvious directionality.

[0082] Specifically, for large-scale arrays, a random phase distribution should be used to achieve the protection mode. For elements requiring a lagging phase, a selectable phase shifter A should be used, while for elements requiring a leading phase, a selectable phase shifter B should be used. For small-scale arrays and subarray structures, a checkerboard phase distribution helps to further improve the protection level. This requires that the phase difference between adjacent elements be maintained at 180°. A feasible approach is to use the following phase distribution form.

[0083]

[0084] The above formula gives the distribution of additional phase values ​​provided by the selectable phase shifter in the protection mode of a 4×4 array. For array element phases less than 0, selectable phase shifter A is used; for array element phases greater than 0, selectable phase shifter B is used.

[0085] The additional phase provided by the selectable phase shifter in protection mode causes AF(φ,θ) to no longer maintain the converged beam and high gain of the normal mode, but instead form a divergent beam and low gain array factor, thus achieving the protection effect. This scheme directly controls the array factor. When the array size increases, the newly added array elements will also participate in cancellation, rather than increasing the array factor. The final effect is that the protection level of this protection method increases with the size of the array.

[0086] A method for protecting an array antenna based on an energy selective phase shifter includes the following steps:

[0087] S1. In normal mode, the PIN diodes in both energy selection phase shifter A and energy selection phase shifter B are not conducting; the PIN diodes are treated as capacitors, and energy selection phase shifters A and B remain transparent, providing no phase shift value or signal attenuation.

[0088] S2. When a high-power microwave irradiates the array antenna protection system, if the high-power radio frequency signal coupled into the system from the array antenna causes the voltage across the PIN diode to exceed the conduction threshold, the PIN diode in the energy selection phase shifter A and energy selection phase shifter B will be adaptively activated to conduct, thereby enabling energy selection phase shifter A and energy selection phase shifter B to provide additional phase shift values, and causing the array antenna protection system to enter the adaptive protection mode.

[0089] In step S1, under normal mode, the PIN diodes in both energy-selective phase shifter A and energy-selective phase shifter B are not conducting; the PIN diodes are treated as capacitors. Energy-selective phase shifters A and B remain transparent, providing no phase shift value and signal attenuation. The principle behind this is as follows:

[0090] A1. In the energy selective phase shifter A, the first capacitor C1, two PIN diodes of opposite polarity connected in parallel across the first capacitor C1, and the first inductor L1 form a resonant structure, providing no additional phase shift in the transmission path; the second capacitor C2, two PIN diodes of opposite polarity connected in parallel across the second capacitor C2, and the second inductor L2 form a resonant structure, also providing no additional phase shift in the transmission path; the third inductor L3 and two PIN diodes of opposite polarity connected in parallel across the third inductor L3 block the grounding branch, making the branch invisible to the transmission path; therefore, the energy selective phase shifter A remains transparent, providing no phase shift value or signal attenuation;

[0091] A2. In the energy selective phase shifter B, the fourth inductor L4, the two PIN diodes with opposite polarities connected in parallel across the fourth inductor L4, and the fourth capacitor C4 form a resonant structure, providing no additional phase shift in the transmission path; the fifth inductor L5, the two PIN diodes with opposite polarities connected in parallel across the fifth inductor L5, and the fifth capacitor C5 form a resonant structure, also providing no additional phase shift in the transmission path; the seventh inductor L7, the two PIN diodes with opposite polarities connected in parallel across the seventh inductor L7 block the grounding branch, making the branch invisible to the transmission path; therefore, the energy selective phase shifter B remains transparent, providing no phase shift value or signal attenuation.

[0092] In step S2, when high-power microwaves irradiate the array antenna protection system, if the high-power radio frequency signal coupled into the system from the array antenna causes the voltage across the PIN diode to exceed the conduction threshold, the PIN diodes in energy selective phase shifters A and B are adaptively activated to conduct, thereby enabling energy selective phase shifters A and B to provide additional phase shift values. The principle behind this allows the array antenna protection system to enter the adaptive protection mode is as follows:

[0093] B1. When the PIN diode in energy selection phase shifter A is turned on:

[0094] Two PIN diodes of opposite polarity connected in parallel across the first capacitor C1 short-circuit the first capacitor C1; two PIN diodes of opposite polarity connected in parallel across the second capacitor C2 short-circuit the second capacitor C2; two PIN diodes of opposite polarity connected in parallel across the third inductor L3 short-circuit the third inductor L3.

[0095] At this point, the first inductor L1, the second inductor L2, and the third capacitor C3 form a T-type phase-shifting network, which plays a phase-shifting role;

[0096] B2. When the PIN diode of B in the energy selection phase shifter is turned on:

[0097] The two PIN diodes with opposite polarities connected in parallel across the fourth inductor L4 cause the fourth inductor L4 to short-circuit.

[0098] The two PIN diodes with opposite polarities connected in parallel across the fifth inductor L5 cause the fifth inductor L5 to short-circuit.

[0099] The two PIN diodes with opposite polarities connected in parallel across the seventh inductor L7 cause the seventh inductor L7 to short-circuit.

[0100] The fourth capacitor C4, the fifth capacitor C5, and the sixth inductor L6 form a T-type phase-shifting network, which plays a phase-shifting role.

[0101] B3. To ensure duality between energy-selective phase shifter A and energy-selective phase shifter B, let

[0102]

[0103] This results in energy selection phase shifter A and energy selection phase shifter B having opposite phase shift values ​​in protection mode;

[0104] B4. Since energy selective phase shifter A and energy selective phase shifter B are set alternately, when the signal from energy selective phase shifter A and the signal from energy selective phase shifter B enter the power divider for synthesis, the high-power signal that has been phase-shifted will be integrated and canceled, thereby preventing excessively high-power signals from entering the later-stage transceiver equipment.

[0105] In the embodiments of this application, to further illustrate the protection method, a prototype operating at 2.3-2.4 GHz was designed, and the exploded view of the prototype is shown below. Figure 4 As shown, the entire structure comprises three metal layers and two dielectric layers. The ground plane (GND) is almost entirely covered by metal. Between the antenna layer and GND is a 2.1mm thick FR-4 (relative permittivity 4.3), and between the feed layer and GND is a 0.8mm thick F4B (relative permittivity 2.2). The multilayer composite board has an outline dimension of 350mm × 350mm. This is a 4×4 two-dimensional planar array with uniformly arranged patch antenna elements, each spaced half the wavelength of the center frequency in both dimensions. The elements are back-fed and connected to the feed circuitry via metallized vias (which penetrate both substrate layers).

[0106] Details of the selectable phase shifter section and power divider are as follows: Figure 5 As shown, the selectable phase shifter is the first-level network closest to the antenna, and it can be divided into two types, A and B, depending on its position. After the selectable phase shifter, a two-stage Wilkinson power divider network combines the four array element antennas and the subsequent selectable phase shifters into a single port. This 2×2 structure is called a subarray. The prototype contains a total of four such subarrays.

[0107] In this embodiment, selectable phase shifter A provides a -90° phase shift in guard mode, while selectable phase shifter B provides a +90° phase shift in guard mode. Both phase shifters are implemented using surface-mount components. The circuit schematic for selectable phase shifter A is shown below. Phase shifters A and B are arranged in a chessboard pattern in the array, with each type of selectable phase shifter always adjacent to the other in either the x or y direction. These phase shifters are connected to the GND layer from the antenna layer via metallized vias to ground. (These vias do not reach the Fr-4 layer.)

[0108] The protection performance and beam scanning performance of the original device were verified through full-wave simulation and actual fabrication testing. Full-wave simulation results show that the 2×2 subarray has good matching in normal mode, and the voltage standing wave ratio (VSWR) is less than 2 across the entire frequency band. Figure 6 As shown.

[0109] The subarray has a focused beam in normal mode, providing a maximum gain of 8.8 dBi in the main lobe direction, such as... Figure 7 As shown. In protection mode, the subarray beam diverges in a cloverleaf shape, providing a maximum protection level of 45dB, as... Figure 8 As shown. When considering a larger 4×4 array, the protection level is further improved to 52dB due to the participation of more array elements in the selective beamforming process, as follows. Figure 9 As shown, the normal mode is Figure 9 (a) and protection mode are Figure 9 (b) in the diagram. This confirms the scalability of the protection level.

[0110] The experimental results show that the prototype can perform beam electronic scanning in the H-plane. Although the original unit was not specifically designed for scanning performance, it can still achieve a scanning angle of 15°. This demonstrates the compatibility between the protection method and beam electronic scanning, with the azimuth angle and normalized gain as shown... Figure 10 As shown, applying selective beamforming to an array antenna does not affect its beam scanning capability.

Claims

1. A protection system for an array antenna based on an energy selective phase shifter, characterized in that: Includes an array antenna, a power divider, and multiple energy-selective phase shifters; The input of each energy selective phase shifter is connected to the array antenna through an array element feed network, and the output of each energy selective phase shifter is connected to a power divider. The output of the power divider is used to output signals to the external device and transmit them to the back-end transceiver. The energy selection phase shifter is used to adjust the phase of signals with power levels greater than the threshold, and the power divider is responsible for integrating and canceling these phase-shifted high-power signals. The energy selective phase shifter is divided into two types: energy selective phase shifter A and energy selective phase shifter B. Energy selective phase shifter A provides a hysteretic additional phase shift value in protection mode, while energy selective phase shifter B provides a leading phase shift value in protection mode. The energy selective phase shifter is alternately set as energy selective phase shifter A and energy selective phase shifter B.

2. The array antenna protection system based on an energy selective phase shifter according to claim 1, characterized in that: The array antenna includes multiple antenna elements, and the number of antenna elements is the same as that of the energy selective phase shifters and they correspond one-to-one. Each energy selective phase shifter is connected to the corresponding antenna element through an array element feed network.

3. The array antenna protection system based on an energy selective phase shifter according to claim 2, characterized in that: The array element feeding network includes an array element antenna balun structure and an electronic phase shifter connected in sequence. The balun structure is responsible for balancing the array element feeding, and the electronic phase shifter is used to realize the beam scanning capability of the array antenna.

4. The array antenna protection system based on an energy selective phase shifter according to claim 1, characterized in that: The energy selective phase shifter A includes capacitors C1, C2, and C3, and inductors L1, L2, and L3. The first terminal of capacitor C1 serves as the input terminal of the energy selective phase shifter A. The second terminal of capacitor C1 is connected to the first terminal of capacitor C2 via inductors L1 and L2, and the second terminal of capacitor C2 serves as the output terminal of the energy selective phase shifter A. The first terminal of capacitor C3 is connected between inductors L1 and L2, and the second terminal of capacitor C3 is grounded via inductor L3. Two PIN diodes of opposite polarity are connected in parallel across the terminals of each of the first capacitor C1, second capacitor C2, and third inductor L3.

5. The array antenna protection system based on an energy selective phase shifter according to claim 1, characterized in that: The energy selective phase shifter B includes capacitors, fourth inductor L4, fifth inductor L5, sixth inductor L6, seventh inductor L7, fourth capacitor C4, and fifth capacitor C5. The first terminal of the fourth inductor L4 serves as the input terminal of the energy selective phase shifter B. The second terminal of the fourth inductor L4 is connected to the first terminal of the fifth inductor L5 in sequence through the fourth capacitor C4 and the fifth capacitor C5. The second terminal of the fifth inductor L5 serves as the output terminal of the energy selective phase shifter B. The first terminal of the sixth inductor L6 is connected between the fourth capacitor C4 and the fifth capacitor C5. The second terminal of the sixth inductor L6 is grounded through the seventh inductor L7. Two PIN diodes with opposite polarities are connected in parallel at both ends of the fourth inductor L4, the fifth inductor L5, and the seventh inductor L7.

6. A method for protecting an array antenna based on an energy selective phase shifter, based on the system described in any one of claims 1 to 5, characterized in that: include: S1. In normal mode, the PIN diodes in both energy selection phase shifter A and energy selection phase shifter B are not conducting; the PIN diodes are treated as capacitors, and energy selection phase shifters A and B remain transparent, providing no phase shift value or signal attenuation. S2. When a high-power microwave irradiates the array antenna protection system, if the high-power radio frequency signal coupled into the system from the array antenna causes the voltage across the PIN diode to exceed the conduction threshold, the PIN diode in the energy selection phase shifter A and energy selection phase shifter B will be adaptively activated to conduct, thereby enabling energy selection phase shifter A and energy selection phase shifter B to provide additional phase shift values, and causing the array antenna protection system to enter the adaptive protection mode.

7. The array antenna protection method based on energy selective phase shifter according to claim 6, characterized in that: In step S1, under normal mode, the PIN diodes in both energy-selective phase shifter A and energy-selective phase shifter B are not conducting; the PIN diodes are treated as capacitors. Energy-selective phase shifters A and B remain transparent, providing no phase shift value and signal attenuation. The principle behind this is as follows: A1. In the energy selective phase shifter A, the first capacitor C1, two PIN diodes of opposite polarity connected in parallel across the first capacitor C1, and the first inductor L1 form a resonant structure, providing no additional phase shift in the transmission path; the second capacitor C2, two PIN diodes of opposite polarity connected in parallel across the second capacitor C2, and the second inductor L2 form a resonant structure, also providing no additional phase shift in the transmission path; the third inductor L3 and two PIN diodes of opposite polarity connected in parallel across the third inductor L3 block the grounding branch, making the branch invisible to the transmission path; therefore, the energy selective phase shifter A remains transparent, providing no phase shift value or signal attenuation; A2. In the energy selective phase shifter B, the fourth inductor L4, the two PIN diodes with opposite polarities connected in parallel across the fourth inductor L4, and the fourth capacitor C4 form a resonant structure, providing no additional phase shift in the transmission path; the fifth inductor L5, the two PIN diodes with opposite polarities connected in parallel across the fifth inductor L5, and the fifth capacitor C5 form a resonant structure, also providing no additional phase shift in the transmission path; the seventh inductor L7, the two PIN diodes with opposite polarities connected in parallel across the seventh inductor L7 block the grounding branch, making the branch invisible to the transmission path; therefore, the energy selective phase shifter B remains transparent, providing no phase shift value or signal attenuation.

8. The array antenna protection method based on energy selective phase shifter according to claim 6, characterized in that: In step S2, when high-power microwaves irradiate the array antenna protection system, if the high-power radio frequency signal coupled into the system from the array antenna causes the voltage across the PIN diode to exceed the conduction threshold, the PIN diodes in energy selective phase shifters A and B are adaptively activated to conduct, thereby enabling energy selective phase shifters A and B to provide additional phase shift values. The principle behind this allows the array antenna protection system to enter the adaptive protection mode is as follows: B1. When the PIN diode in energy selection phase shifter A is turned on: Two PIN diodes of opposite polarity connected in parallel across the first capacitor C1 short-circuit the first capacitor C1; two PIN diodes of opposite polarity connected in parallel across the second capacitor C2 short-circuit the second capacitor C2; two PIN diodes of opposite polarity connected in parallel across the third inductor L3 short-circuit the third inductor L3. At this point, the first inductor L1, the second inductor L2, and the third capacitor C3 form a T-type phase-shifting network, which plays a phase-shifting role; B2. When the PIN diode of B in the energy selection phase shifter is turned on: The two PIN diodes with opposite polarities connected in parallel across the fourth inductor L4 cause the fourth inductor L4 to short-circuit. The two PIN diodes with opposite polarities connected in parallel across the fifth inductor L5 cause the fifth inductor L5 to short-circuit. The two PIN diodes with opposite polarities connected in parallel across the seventh inductor L7 cause the seventh inductor L7 to short-circuit. The fourth capacitor C4, the fifth capacitor C5, and the sixth inductor L6 form a T-type phase-shifting network, which plays a phase-shifting role. B3. To ensure duality between energy-selective phase shifter A and energy-selective phase shifter B, let This results in energy selection phase shifter A and energy selection phase shifter B having opposite phase shift values ​​in protection mode; B4. Since energy selective phase shifter A and energy selective phase shifter B are set alternately, when the signal from energy selective phase shifter A and the signal from energy selective phase shifter B enter the power divider for synthesis, the high-power signal that has been phase-shifted will be integrated and canceled, thereby preventing excessively high-power signals from entering the later-stage transceiver equipment.

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