Phase-reconfigurable ultra-wideband three-dimensional frequency selective surface and application

Abstract

The invention discloses a phase-reconfigurable ultra-wideband three-dimensional frequency selective surface and application, and belongs to the technical field of reconfigurable frequency selective surfaces, the surface comprises M columns of units, and N units in each column are simultaneously controlled by a signal provided by an external control circuit; each basic unit comprises a slot line layer, an Ro4003C dielectric layer, a microstrip line layer and a metal through hole used for energy transmission between the slot line layer and the microstrip line layer. The Pin diodes are introduced between the slot line rings on the slot line layer to serve as reconfigurable devices, symmetrical phase reversal of current is achieved, 1-Bit regulation and control are conducted on the phase of transmission waves, control is accurate, and the switching speed is high. According to the invention, ultra-wideband frequency selection can be realized for incident electromagnetic waves with an incident angle in a range of 0-60 degrees, two working states with a phase difference of 180 degrees are realized in a passband, and meanwhile, the ultra-wideband frequency selection filter has the advantages of low insertion loss and high phase precision, and can be widely applied to dynamic regulation and control of space electromagnetic waves of a new-generation radio subsystem.

Description

Technical Field

[0001] The present invention relates to the technical field of reconfigurable frequency selective surfaces, and particularly to a phase-reconfigurable ultra-wideband three-dimensional frequency selective surface and its application. Background Art

[0002] A frequency selective surface is a technology that uses a periodic structure to selectively regulate electromagnetic waves and is widely used in fields such as communication, radar, and stealth. Compared with two-dimensional FSS, three-dimensional frequency selective surfaces improve the adaptability to polarization states and incident angles by introducing a three-dimensional structure and exhibit more excellent performance in broadband response and spatial waveguide conversion. Common 3D FSS unit structures include stacked microstrip lines, square coaxial waveguides, and slot lines, which can achieve frequency and polarization selection functions within a specific frequency band and support various electromagnetic characteristic regulation requirements. However, most current 3D FSSs are static structures, lacking tunability and unable to adapt to dynamic application scenarios. To improve their reconfigurability, research has introduced tuning elements such as PIN diodes, varactor diodes, MEMS devices, and photosensitive materials to achieve switch control or continuous adjustment of the unit response characteristics. Some designs have achieved 1-Bit or 2-Bit phase reconfiguration and transmission-reflection dual-mode regulation functions, verifying the potential of three-dimensional structures in programmable electromagnetic structures. However, existing solutions mostly focus on a single performance index and are difficult to simultaneously consider amplitude filtering ability and stable phase regulation ability, limiting their application expansion in emerging scenarios such as high-speed communication and intelligent reflecting surfaces. Therefore, developing a new type of 3D FSS structure with broadband response, phase controllability, and structural programmability remains an important research direction in this field. Summary of the Invention

[0003] Technical Problem:

[0004] The purpose of the present invention is to provide a phase-reconfigurable ultra-wideband three-dimensional frequency selective surface to solve the technical problems mentioned in the background art and achieve amplitude filtering and phase regulation of incident electromagnetic waves within a wide frequency band.

[0005] Technical Solution:

[0006] The purpose of the present invention is to provide a phase-reconfigurable ultra-wideband three-dimensional frequency selective surface, which includes: N×M transmission unit cells arranged in a periodic manner. The array contains M columns of cells, and N cells in each column are simultaneously controlled by a signal provided by an external control circuit; while performing ultra-wideband filtering on incident electromagnetic waves, 1-Bit transmission phase regulation is performed in real-time and quickly.

[0007] Wherein, the basic transmission unit includes, from top to bottom, in sequence:

[0008] The first layer is the slot line layer, including a first wide slot, a second wide slot, a first Pin diode, a second Pin diode, a first circular ring slot, a second circular ring slot, and an isolation capacitor. Among them, the two Pin diodes have the same model and are placed in opposite directions within the circular ring slots. The length and width dimensions of the two wide slots are the same, and the dimensions of the two circular ring slots are the same. The placement method of the isolation capacitor is the same as that of the Pin diodes.

[0009] The second layer is the Ro4003C dielectric substrate layer.

[0010] The third layer is the microstrip line layer, including a first microstrip line, a second microstrip line, a first DC feeder, a second DC feeder, a first isolation inductor, and a second isolation inductor. The isolation inductor connects one end of the DC feeder to the second microstrip line, and the first microstrip line and the second microstrip line face perpendicular to each other.

[0011] Among them, two metal vias are provided between the first layer and the third layer. The metal vias provide a radio frequency path between the slot line and the microstrip line and provide DC power supply for the Pin diodes. The metal vias penetrate the slot line layer, the Ro4003C dielectric substrate layer, and the microstrip line layer.

[0012] In the DC feeding perspective of the slot line layer, the inner metal of the circular ring slot serves as the bias voltage application end, and the outer metal of the slot line serves as the DC feeding ground; the bias current reaches the second microstrip line through the DC feeder and flows through the via to the inner metal of the circular ring slot.

[0013] The Pin diode is in the conducting working state when the bias voltage is 2.5V and in the cut-off working state when the bias voltage is -2.5V; the internal equivalent circuits of the Pin diode in the two working states of conduction and cut-off are different, thus forming different responses to the electromagnetic wave flowing through the Pin diode.

[0014] The positive electrode of the first Pin diode is placed inside the circular ring slot, and the negative electrode of the second Pin diode is placed inside the circular ring slot; when the bias voltage is +2.5V, the first Pin diode conducts and the second Pin diode cuts off; when the bias voltage is -2.5V, the first Pin diode cuts off and the second Pin diode conducts.

[0015] For the Pin diode, in the two working states under the two bias voltages, the wide slot current on the conducting Pin diode side flows through the first via to the second microstrip line, so that within a given frequency band, the transmission phase interval of the incident electromagnetic wave is 180°.

[0016] Under the condition of normal incidence of plane waves, the basic transmission units are arranged in a two-dimensional periodic manner and exhibit an alternating distribution characteristic in the electric field direction and the magnetic field direction. Specifically, in the magnetic field direction, the transmission units are arranged along the period Py to achieve efficient coupling and response to electromagnetic waves in the magnetic field direction; in the electric field direction, adjacent transmission units are connected through the period Px to form a continuous channel, thereby enhancing the electromagnetic coupling strength and phase stability of the overall structure.

[0017] The lengths of the wide slot, the circular ring slot, and the second microstrip line are all one-quarter of the electrical wavelength to achieve a stable modified Chebyshev filter response.

[0018] In the two operating states of the basic transmission unit under different bias voltages, the structure maintains a high degree of symmetry. Due to this symmetry characteristic, when modulating the phase of the incident electromagnetic wave, it can ensure that the amplitude filtering performance of the incident electromagnetic wave remains consistent, thereby achieving a stable phase adjustment effect without affecting the amplitude response of the electromagnetic wave.

[0019] The period along the electric field direction is Px = 12 mm, and the period along the magnetic field direction is Py = 10 mm; the length of the wide slot structure is l1 = 10.85 mm, and the width is w1 = 3.5 mm; the inner diameter of the circular ring slot is R = 2.8 mm, and the slot width is w2 = 0.3 mm; the length of the first microstrip line is l3 = 5.3 mm, the length of the second microstrip line is l2 = 14.5 mm, and the width is w3 = 0.58 mm.

[0020] The thickness of the Ro4003C dielectric substrate layer is 0.508 mm, the metal thickness of the first layer and the third layer is both 0.035 mm, and the diameter of the metal through-hole is 0.58 mm.

[0021] The present invention also provides an application of the ultra-wideband three-dimensional frequency selective surface in beam scanning control of a wireless communication system. By encoding with an external control circuit, dynamic regulation of the transmission phase is achieved, supporting the deflection of the electromagnetic wave pattern. Specifically, it includes the following steps:

[0022] Based on the target beam direction, calculate the phase offset required for each transmission unit, and quantize the phase offset into binary coding;

[0023] Apply a ±2.5 V bias voltage to the Pin diode of each transmission unit through an external control circuit to switch its on / off state and achieve a 180° phase difference;

[0024] By adjusting the phase distribution of different units in the array, generate a preset main lobe direction of the electromagnetic wave;

[0025] Integrate sensors to monitor the beam pointing error, and combine an adaptive algorithm to dynamically adjust the coding strategy to improve the beam stability;

[0026] Within the 3 - 7 GHz frequency band, phase encoding is independently regulated in sub - frequency bands, supporting multi - frequency point synchronous beam scanning.

[0027] Beneficial effects:

[0028] 1. In the present invention, two Pin diodes are symmetrically placed inside the circular groove of the slot - line layer. By applying a bias voltage of ±2.5V to control their alternating conduction / cut - off, the direction of the current path is changed, realizing a 180° phase switching of the transmitted wave.

[0029] The resulting beneficial effects are:

[0030] 1) Through binary voltage switching, the phase difference is stabilized within 180° ± 10°, with a fast response speed, suitable for real - time dynamic regulation scenarios.

[0031] 2) The structure is highly symmetric in two working states, ensuring that the amplitude filtering characteristics remain consistent during the phase switching process, and avoiding interference of phase regulation on the pass - band performance.

[0032] 2. The present invention combines the slot - line layer, micro - strip line layer and quarter - wavelength structure to simultaneously achieve ultra - wideband amplitude filtering (relative bandwidth 80%) and phase regulation functions within the 3 - 7 GHz frequency band.

[0033] The resulting beneficial effects are:

[0034] 1) The - 3dB pass - band covers 3 - 7 GHz, and the out - of - band rejection exceeds - 10dB, meeting the requirements of multi - band communication.

[0035] 2) The filtering and phase - modulation functions are integrated into a single structure, simplifying the system complexity and reducing the hardware cost.

[0036] 3. The transmission unit of the present invention adopts a three - dimensional stacked design, periodically arranged along the electric - field and magnetic - field directions (Px = 12mm, Py = 10mm), and enhancing the inter - layer coupling through metal vias.

[0037] The resulting beneficial effects are:

[0038] 1) Within the incident - angle range of 0 - 60°, the pass - band amplitude fluctuation is less than - 4dB, and the phase - difference fluctuation is less than 15°, suitable for multi - angle incident scenarios.

[0039] 2) The three - dimensional layout enhances the response ability to electromagnetic waves of different polarizations, improving the flexibility of spatial beam regulation.

[0040] 4. The present invention uses a low - loss dielectric substrate Ro4003C (tanδ = 0.002), combines isolation capacitors and inductors to isolate RF and DC feed interference, and optimizes the via size (diameter 0.58mm) to reduce RF loss.

[0041] The beneficial effects produced are as follows:

[0042] 1) The transmission amplitude within the passband is greater than -2 dB, significantly reducing signal attenuation.

[0043] 2) The phase difference fluctuation is less than 10°, meeting the requirements of high-precision beamforming.

[0044] 5. Dynamically adjust the phase distribution of each unit through external control circuit coding, support multi-frequency point synchronous beam scanning, and integrate an adaptive algorithm to correct the beam pointing error in real time.

[0045] The beneficial effects produced are as follows:

[0046] 1) Support independent regulation of phase coding for different frequency bands, adapting to the requirements of multi-frequency communication systems.

[0047] 2) Realize the deflection of the main lobe direction (such as 0° - 60°) through array phase regulation, improving the coverage range and anti-interference ability of the wireless communication system.

[0048] In summary, through the innovative three-dimensional structure design, symmetric configuration of PIN diodes, and ultra-wideband integrated regulation, the present invention solves the problems of insufficient adjustability, limited bandwidth, and low phase accuracy of traditional static FSS, and has high stability, low loss, and wide-angle adaptability, and can be widely applied to fields such as 5G / 6G communication, intelligent reflecting surface, and radar stealth. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of the array form of the reconfigurable three-dimensional frequency selective surface structure provided by the embodiment of the present invention;

[0050] Figure 2 Front view of the transmissive basic unit of the reconfigurable three-dimensional frequency selective surface provided by the embodiment of the present invention;

[0051] Figure 3 Back view of the transmissive basic unit of the reconfigurable three-dimensional frequency selective surface provided by the embodiment of the present invention;

[0052] Figure 4 Simulation curve graph of the transmission amplitude varying with frequency for each state (2 states) of the reconfigurable three-dimensional frequency selective surface under 1-bit coding provided by the embodiment of the present invention;

[0053] Figure 5 Simulation curve graph of the transmission phase and phase difference varying with frequency for each state (2 states) of the reconfigurable three-dimensional frequency selective surface under 1-bit coding provided by the embodiment of the present invention;

[0054] Figure 6The graph showing the variation of the transmission amplitude with frequency of the reconfigurable three-dimensional frequency selective surface provided by the embodiments of the present invention under different incident angles;

[0055] Figure 7 The graph showing the variation of the phase difference between two operating states with frequency of the reconfigurable three-dimensional frequency selective surface provided by the embodiments of the present invention under different incident angles;

[0056] Figure 8 The normalized two-dimensional pattern of the reconfigurable three-dimensional frequency selective surface array provided by the embodiments of the present invention under different coding conditions. (a) is the normalized two-dimensional pattern measured at 3.5 GHz, (b) is the normalized two-dimensional pattern measured at 4.5 GHz, (c) is the normalized two-dimensional pattern measured at 5.5 GHz, and (d) is the normalized two-dimensional pattern measured at 6.5 GHz. Detailed implementation manners

[0057] The following embodiments described with reference to the drawings are used to exemplarily illustrate the technical solution of a phase-reconfigurable ultra-wideband three-dimensional frequency selective surface of the present invention. Those skilled in the art should understand that these implementation manners are not limitations on the present invention, but are used to explain the present invention.

[0058] Embodiment 1

[0059] See Figures 1 - 3 , this embodiment provides a phase-reconfigurable ultra-wideband three-dimensional frequency selective surface, which includes: N×M transmission basic unit periods arranged in an array. The array contains M columns of units, and N units in each column are simultaneously controlled by a signal provided by an external control circuit.

[0060] In this embodiment, the transmission basic unit includes, from top to bottom:

[0061] The first layer is the slot line layer 1, which includes the first wide slot 1.1, the second wide slot 1.2, the first Pin diode 1.3, the second Pin diode 1.4, the first circular ring slot 1.5, the second circular ring slot 1.6, and the isolation capacitor 1.7; among them, the sizes of the 2 wide slots are the same, the sizes of the 2 circular ring slots are the same, and the models of the 2 Pin diodes are the same.

[0062] The second layer is the Ro4003C dielectric substrate layer 2;

[0063] The third layer is the microstrip line layer 3, which includes the first microstrip line 3.1, the second microstrip line 3.2, the first DC feeder 3.3, the second DC feeder 3.4, the first isolation inductor 3.5, and the second isolation inductor 3.6. The first microstrip line 3.1 is perpendicular to the second microstrip line 3.2.

[0064] Two metal vias 4 are arranged at both ends of the second microstrip line 3.2. The metal vias 4 penetrate through the slot line layer 1, the Ro4003C dielectric substrate layer 2 and the microstrip line layer 3. The metal vias 4 play the role of allowing radio frequency signals to pass between the slot line and the microstrip line, and at the same time allowing DC feeding to reach one end of the PIN diode.

[0065] Specifically, in this embodiment, the models of the first PIN diode 1.3 and the second PIN diode 1.4 used are both ARW3172. This type of PIN diode has two operating states of conduction and cut-off when the bias voltages are 2.5V and -2.5V respectively.

[0066] Specifically, in this embodiment, the model of the isolation capacitor 1.7 used is GJM0335C1E8R0BB01. This type of capacitor allows radio frequency signals to pass through and isolates DC signals to avoid DC short circuit caused by the metal inside the second circular groove 1.6 contacting the metal outside the slot line.

[0067] Specifically, in this embodiment, the models of the first isolation inductor 3.5 and the second isolation inductor 3. (should be 3.6) are both LQW15AN40NJ00. This type of inductor allows DC signals to pass through and isolates radio frequency signals to avoid the DC feeding network affecting the radio frequency path.

[0068] Specifically, in this embodiment, the positive electrode of the first PIN diode 1.3 and the negative electrode of the second PIN diode 1.4 are placed on the inner metal of the first circular groove 1.5, and the other electrodes of the two PIN diodes are placed on the metal outside the slot line.

[0069] Specifically, in this embodiment, the DC bias reaches the second microstrip line 3.2 through the DC feeder, and then reaches the inner metal of the first circular groove 1.5 through the first metal via 4.1 to control the state of the PIN diode. The metal outside the slot line in the slot line layer 1 serves as the DC bias ground terminal.

[0070] Specifically, in this embodiment, when the DC bias is 2.5V, the first PIN diode 1.3 is in the conduction state and the second PIN diode 1.4 is in the cut-off state; when the DC bias is -2.5V, the first PIN diode 1.3 is in the cut-off state and the second PIN diode 1.4 is in the conduction state; thus, under the two bias voltages, the currents on different sides of the first wide groove 1.1 flow to the second microstrip line 3.2.

[0071] Specifically, in this embodiment, when the bias voltages are 2.5V and -2.5V, within the given frequency band, the electromagnetic wave transmission phase interval is 180°.

[0072] Specifically, in this embodiment, when the bias voltages are 2.5V and -2.5V, the electromagnetic wave transmission amplitude is greater than 2dB within a given frequency band.

[0073] Specifically, the metal-dielectric-metal three-layer sandwich structure provided in this embodiment can be easily fabricated using standard printed circuit (PCB) double-layer board technology. More specifically:

[0074] The thickness of the Ro4003C dielectric substrate layer 2 is 0.508mm, the relative dielectric constant is 3.55, the loss tangent is 0.002, and the diameters of the first metal via 4.1 and the second metal via 4.2 are both 0.58mm;

[0075] The surface copper layer of the slot line layer 1 has a thickness of 0.035mm and is mainly composed of 2 wide slots and 2 circular ring slots, where a part of the circular ring slot is cut off by the wide slot to achieve a low-loss transition of the RF path;

[0076] The surface copper layer of the microstrip line layer 3 has a thickness of 0.035mm and is mainly composed of 2 sections of DC feed lines and 2 sections of microstrip lines, and the two sections of microstrip lines are perpendicular to each other;

[0077] The period of the transmission basic unit along the electric field direction is Px = 12mm, and the period along the magnetic field direction is Py = 10mm; the length of the wide slot structure is l1 = 10.85mm, the width is w1 = 3.5mm; the inner diameter of the circular ring slot is R = 2.8mm, the slot width is w2 = 0.3mm; the length of the first microstrip line is l3 = 5.3mm, the length of the second microstrip line is l2 = 14.5mm, and the width is w3 = 0.58mm.

[0078] The transmission amplitudes in two states are as Figure 4 shown. The -3dB bandwidth is 3 - 7GHz (relative bandwidth 80%), which is better than the existing reports; within the frequency bands of 0 - 2.5GHz and 7.5 - 10GHz, the amplitude suppression of the incident electromagnetic wave exceeds -10dB; the transmission passbands in two states are basically the same; therefore, the present invention can achieve an ultra-wideband filtering function for the amplitude of the incident electromagnetic wave.

[0079] The transmission phases and phase intervals in two states are as Figure 5 shown. Within the 3 - 7GHz passband, the phase difference between the two operating states is 180, and the phase fluctuation is less than 10°, which conforms to the 1-Bit control characteristic; therefore, the present invention can achieve efficient transmission phase control for the incident electromagnetic wave within an ultra-wide frequency band.

[0080] The transmission amplitudes and phase differences at different incident angles are as Figure 6 and Figure 7As shown, when the plane electromagnetic wave is incident at an angle of 0 - 60°, the transmission amplitude within the passband is greater than -4 dB, and the phase difference fluctuation is less than 15°, still maintaining good out-of-band rejection; indicating that the present invention can have ultra-wideband amplitude filtering and phase regulation functions both in the case of normal incidence and oblique incidence of electromagnetic waves, and has good angle-insensitive characteristics.

[0081] The beam steering ability of this embodiment is as Figure 8 shown. Codes with beam deflection angles of 0°, 15°, 30°, 45°, and 60° are pre-calculated, and four frequency points (3.5 GHz, 4.5 GHz, 5.5 GHz, and 6.5 GHz) are selected within the passband for far-field pattern tests; the test results of the normalized two-dimensional pattern are shown in the figure, and the deflected angles are in agreement with the theoretical calculations; therefore, the present invention is capable of realizing the beam scanning control function.

[0082] It should be further noted that the transmission passband of the basic unit provided in this embodiment is 3 - 7 GHz. If the unit size is adjusted, its operating frequency band can be flexibly adjusted to meet the performance of good 1-Bit phase reconfigurability.

[0083] Embodiment 2

[0084] This embodiment provides an application of the ultra-wideband three-dimensional frequency selective surface in beam scanning control of a wireless communication system. The dynamic regulation of the transmission phase is realized through external control circuit coding, and the deflection of the electromagnetic wave pattern is supported. The specific steps are as follows:

[0085] Based on the target beam direction, calculate the required phase offset of each transmission unit, and quantize the phase offset into binary coding;

[0086] Apply ±2.5 V bias voltages to the Pin diodes of each transmission unit through an external control circuit to switch its on / off state and achieve a 180° phase difference;

[0087] Generate the preset main lobe direction of the electromagnetic wave by adjusting the phase distribution of different units in the array;

[0088] Integrate sensors to monitor the beam pointing error, and combine an adaptive algorithm to dynamically adjust the coding strategy to improve the beam stability;

[0089] Within the 3 - 7 GHz frequency band, independently regulate the phase coding in different frequency bands to support multi-frequency point synchronous beam scanning.

[0090] For the parts not detailed in the present invention, they are all well-known technologies to those skilled in the art.

[0091] Based on the technical concept of the present invention, those skilled in the art can achieve improvements including but not limited to the following through conventional modifications and equivalent substitutions within the scope of protection defined by the claims: reasonable changes in implementation manners such as adaptive adjustment of material parameters, topological optimization of geometric structures, equivalent substitution of electronic devices, etc. The above technical adjustments all fall within the scope of protection of the patent right of the present invention.

Claims

1. A phase-reconfigurable ultra-wideband three-dimensional frequency selective surface, characterized in that, It includes M columns of units. One same control signal is provided to N transmission units in each column by an external control circuit. Each transmission unit includes: A slot line layer (1), which includes symmetrically arranged first wide slots (1.1) and second wide slots (1.2), first PIN diodes (1.3) and second PIN diodes (1.4), first circular ring slots (1.5) and second circular ring slots (1.6), and isolation capacitors (1.7). The positive poles of the first PIN diodes and the negative poles of the second PIN diodes are both located inside the circular ring slots. A Ro4003C dielectric substrate layer (2), which is located below the slot line layer. A microstrip line layer (3), which includes mutually perpendicular first microstrip lines (3.1) and second microstrip lines (3.2), first DC feed lines (3.3) and second DC feed lines (3.4), first isolation inductors (3.5) and second isolation inductors (3.6). The DC feed lines are connected to the second microstrip lines through the isolation inductors. Metal vias (4), which penetrate the slot line layer, the dielectric substrate layer, and the microstrip line layer, connect the slot line layer and the microstrip line layer, provide a path for RF signals, and provide DC power feeding for the PIN diodes. Among them, when applying ±2.5V bias voltages, the first PIN diodes and the second PIN diodes conduct and cut off alternately, making the phase of the transmitted waves have a 180° interval, and realizing ultra-wideband amplitude filtering within the 3 - 7GHz frequency band.

2. The ultra-wideband three-dimensional frequency selective surface according to claim 1, characterized in that The lengths of the first wide slots (1.1) and the second wide slots (1.2) are 10.85mm, and the widths are 3.5mm. The inner diameters of the first circular ring slots (1.5) and the second circular ring slots (1.6) are 2.8mm, and the slot widths are 0.3mm.

3. The ultra-wideband three-dimensional frequency selective surface according to claim 1, characterized in that, The length of the second microstrip line (3.2) in the microstrip line layer is 14.5mm, the width is 0.58mm, and the length of the first microstrip line (3.1) is 5.3mm.

4. The ultra-wideband three-dimensional frequency selective surface according to claim 1, wherein The diameter of the metal vias (4) is 0.58mm, which penetrates the slot line layer, the dielectric substrate layer, and the microstrip line layer, and connects the second microstrip line (3.2) and the metal inside the circular ring slots.

5. The ultra-wideband three-dimensional frequency selective surface according to claim 1, characterized in that, The isolation capacitors (1.7) are used to isolate RF signals from DC power feeding, and the isolation inductors (3.5, 3.6) are used to isolate the influence of DC power feeding on the RF path.

6. The ultra-wideband three-dimensional frequency selective surface according to claim 1, wherein The period of the transmission unit along the electric field direction is 12mm, and the period along the magnetic field direction is 10mm, and the amplitude filtering and phase regulation performances are kept consistent within the incident angle range of 0 - 60°.

7. The ultra-wideband three-dimensional frequency selective surface according to claim 1, characterized in that The PIN diodes (1.3, 1.4) conduct when biased at +2.5V and cut off when biased at -2.5V. By switching the conduction states, the current path of the wide slots is changed to realize a 180° switching of the transmitted phase.

8. The ultra-wideband three-dimensional frequency selective surface according to claim 7, characterized in that, In the conduction state, the current flows through the wide slot on the side of the conducting PIN diode through the metal via to the second microstrip line. In the cut-off state, the current path is reversed.

9. The ultra-wideband three-dimensional frequency selective surface according to claim 1, wherein The -3dB bandwidth of the transmission unit is 3 - 7GHz, the relative bandwidth is 80%, the out-of-band rejection exceeds -10dB, and the phase difference fluctuation is less than 10°.

10. Application of the ultra-wideband three-dimensional frequency selective surface according to any one of claims 1-9 in beam scanning control of a wireless communication system, characterized in that The dynamic regulation of the transmitted phase is realized through the coding of the external control circuit, which supports the deflection of the electromagnetic wave pattern. Specifically, it includes the following steps: Based on the target beam direction, calculate the required phase offset of each transmission unit, and quantize the phase offset into binary codes. Apply a ±2.5V bias voltage to the Pin diode of each transmission unit through an external control circuit to switch its on / off state and achieve a 180° phase difference; Generate a preset main lobe direction of electromagnetic waves by adjusting the phase distribution of different units in the array; Integrate sensors to monitor the beam pointing error, and combine an adaptive algorithm to dynamically adjust the coding strategy to improve beam stability; Within the 3-7GHz frequency band, independently regulate phase coding in different frequency bands to support multi-frequency point synchronous beam scanning.

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