Polarization reconfigurable antenna based on substrate integrated waveguide and artificial surface plasmon

Abstract

The application relates to a polarization reconfigurable antenna based on a substrate integrated waveguide and an artificial surface plasmon, and belongs to the technical field of antennas. The application aims to solve the problems of fixed polarization characteristics of a traditional antenna, low gain of an existing polarization reconfigurable antenna, and limited beam scanning angle of a leaky-wave antenna. The antenna comprises two groups of 45-degree linear polarization antenna units (SSPP units constructed based on a SIW resonant cavity and a periodic 45-degree rectangular slot) arranged orthogonally and a power divider with a 90-degree phase difference. The power divider is selectively driven to work by controlling the switching state of PIN diodes. By controlling the state of the diodes, dynamic switching of +45-degree linear polarization, -45-degree linear polarization and right-handed circular polarization can be realized. Meanwhile, the antenna has high gain (up to 14.7dBi) and a beam scanning capability of about 43 degrees within a frequency range of 11.5-14.5GHz, and is suitable for wireless communication, radar systems and unmanned aerial vehicle detection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of antennas, and particularly relates to a polarization reconfigurable antenna design, in particular to a polarization reconfigurable antenna technology based on a substrate integrated waveguide (SIW) and a spoof surface plasmon polariton (SSPP). BACKGROUND

[0002] In the fields of modern wireless communication, radar systems, and unmanned aerial vehicle detection, antennas, as the core components of electromagnetic signal transmission, directly affect the communication quality and detection efficiency of the system. With the rapid development of communication technology, the wireless environment is becoming increasingly complex, and higher requirements are put forward for the multifunctionality and adaptability of antennas. Reconfigurable antennas, which can flexibly adjust the working mode (such as polarization state, working frequency, etc.), have become a key technology for coping with complex electromagnetic environments. Polarization reconfigurable antennas can dynamically switch between different polarization modes (linear polarization, circular polarization, etc.), effectively solving problems such as polarization mismatch and multipath interference, and improving communication reliability.

[0003] As a new type of low-profile waveguide structure, substrate integrated waveguide (SIW) realizes electromagnetic wave confinement through the top and bottom metal layers and the periodic arrangement of metal vias on both sides, and has the advantages of low loss, high Q value, and high power capacity of traditional metal waveguides. It is easy to process by PCB technology and integrate with microwave integrated circuits, and is widely used in high-frequency fields.

[0004] Spoof surface plasmon polariton (SSPP) realizes the propagation of surface waves in the microwave and terahertz wave bands by etching periodic slot structures on the surface of metals, and has the characteristics of low loss, adjustable dispersion, and significant slow wave characteristics. It can be used to design high-gain, low-profile, and wide-band antennas, providing a new way to improve antenna radiation performance.

[0005] However, in the field of antennas, the polarization characteristics of traditional antennas are fixed once designed and cannot be dynamically adjusted according to the environment, which can easily lead to signal quality deterioration or even communication interruption due to polarization mismatch and interference. Although existing polarization reconfigurable antennas can achieve polarization switching, they generally have low gain and complex structure, and especially in leaky-wave antennas, the beam scanning angle is limited, which seriously restricts their practical application. Although SIW and SSPP technologies have shown performance advantages in filter devices, how to apply them together in antenna design to break through the technical bottlenecks of existing polarization reconfigurable antennas is still a key problem to be solved.

[0006] Therefore, it is of great significance to develop an antenna with high gain, wide beam scanning range, and flexible polarization reconfiguration capability. SUMMARY

[0007] The purpose of this invention is to address the problems of fixed polarization characteristics in traditional antennas, which cannot be dynamically adjusted to adapt to environmental changes; and the low gain, complex structure, and limited beam scanning angle of existing polarization reconfigurable antennas. This invention provides a polarization reconfigurable antenna that integrates substrate integrated waveguide (SIW) and surface plasmon polariton (SSPP) technologies to design two sets of orthogonal 45° linearly polarized antenna elements. Combined with an adjustable power divider with a 90° phase difference (by controlling the switching state of PIN diodes), it achieves dynamic switching between +45° linear polarization, -45° linear polarization, and right-hand circular polarization, while also possessing high gain and beam scanning capability.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: a polarization reconfigurable antenna based on a substrate integrated waveguide and artificial surface plasmon polaritons, comprising:

[0009] Two sets of orthogonally arranged linearly polarized antenna elements, each set of linearly polarized antenna elements is constructed based on a substrate integrated waveguide resonant cavity. The substrate integrated waveguide resonant cavity has periodically arranged 45° rectangular slots, and the rectangular slots are combined to form artificial surface plasmon polariton units.

[0010] A power divider connected to two sets of linearly polarized antenna elements. The power divider has an input port and two output ports. The two output ports are connected to the two sets of linearly polarized antenna elements one by one, and there is a 90° phase difference between the two output ports.

[0011] The power divider is equipped with at least two PIN diodes. By controlling the switching state of the PIN diodes, the output port is selectively activated to drive the corresponding linearly polarized antenna unit to work, thereby realizing the switching of polarization mode.

[0012] The periodically arranged rectangular slits form a periodic modulation structure, which is used to regulate the surface wave propagation characteristics to achieve beam scanning.

[0013] Furthermore, the rectangular slots are arranged in an anti-symmetrical manner within the substrate integrated waveguide resonant cavity, with the lengths of the rectangular slots on the upper and lower sides varying symmetrically, taking the longitudinal centerline of the substrate integrated waveguide resonant cavity as the boundary.

[0014] Furthermore, the rectangular gaps on both sides above and below the longitudinal center line are staggered along the x and y directions.

[0015] Furthermore, the power divider has a T-shaped structure, including one input port and two output ports, with PIN diodes positioned near the input port.

[0016] Furthermore, the two sets of linearly polarized antenna elements are arranged in parallel and symmetrically, with one set used to radiate +45° linearly polarized waves and the other set used to radiate -45° linearly polarized waves.

[0017] Furthermore, the polarization modes include +45° linear polarization, -45° linear polarization, and right-hand circular polarization;

[0018] When both PIN diodes are in the off state, the two sets of linearly polarized antenna elements work simultaneously to generate right-hand circularly polarized waves.

[0019] When only one PIN diode is turned on, the corresponding set of linearly polarized antenna elements are working, generating either a +45° linearly polarized wave or a -45° linearly polarized wave.

[0020] Furthermore, the linearly polarized antenna element also includes a microstrip line and a trapezoidal transition line. The microstrip line is used to achieve 50Ω input impedance matching, and the trapezoidal transition line is used to optimize the impedance matching effect.

[0021] Furthermore, a metallic reflective surface is provided on the back of the linearly polarized antenna element.

[0022] Furthermore, the period of the periodic modulation structure is a preset value, and the spacing of the rectangular gaps is a preset fixed value.

[0023] Furthermore, a dielectric substrate with a preset relative permittivity is used for fabrication, and the thickness of the dielectric substrate is a preset thickness.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. Flexible polarization reconfigurability: By controlling the state of the PIN diode, it can dynamically switch between +45° linear polarization, -45° linear polarization and right-hand circular polarization modes, effectively dealing with problems such as polarization mismatch and multipath interference, and improving communication reliability in complex environments;

[0026] 2. Excellent gain performance: By leveraging the synergistic effect of SIW and SSPP, impedance matching and surface current distribution are optimized, achieving a maximum gain of 14.7 dBi, thus solving the problem of low gain in existing polarized reconfigurable antennas;

[0027] 3. Wide beam scanning range: By controlling the surface wave propagation characteristics through a periodic modulation structure, a beam scanning angle of approximately 43° can be achieved in the 11.5~14.5GHz frequency band, breaking through the bottleneck of the limited scanning angle of existing leaky wave antennas;

[0028] 4. Stable performance over a wide frequency band: Within the 11.5~14.5GHz frequency band, the reflection coefficient (S) is stable. 11 All values ​​are below -10dB, and the axial ratio (AR) in circular polarization is below 3dB, indicating high radiation efficiency and stable performance.

[0029] 5. Compact structure and easy integration: Based on PCB manufacturing process, the overall size is small (246.9×24.1mm). 2 It is easy to integrate with microwave integrated circuits and is suitable for miniaturized devices such as wireless communication and radar. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of an antenna structure according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the modulation structure according to an embodiment of the present invention, wherein (a) is the non-tilted angle and (b) is the gap misalignment connection;

[0032] Figure 3 This is a schematic diagram of a 45° linearly polarized antenna structure according to an embodiment of the present invention;

[0033] Figure 4 This is an electric field distribution diagram at 12 GHz for a 45° linearly polarized antenna according to an embodiment of the present invention, wherein (a) is an electric field phase of 0° and (b) is an electric field phase of 180°.

[0034] Figure 5 This is a schematic diagram of a power divider structure according to an embodiment of the present invention;

[0035] Figure 6 This is an S-parameter phase diagram of a power divider when the diode state is "00" according to an embodiment of the present invention;

[0036] Figure 7 This is a surface current distribution diagram at 12GHz of a power divider according to an embodiment of the present invention, wherein (a) is a “00” state, (b) is a “10” state, and (c) is a “01” state;

[0037] Figure 8 This is an electric field vector pattern according to an embodiment of the present invention;

[0038] Figure 9 This is a 12GHz electric field distribution diagram according to an embodiment of the present invention, wherein (a) is the “00” state, (b) is the “10” state, and (c) is the “01” state;

[0039] Figure 10 This is an actual sample drawing according to an embodiment of the present invention;

[0040] Figure 11 This is a schematic diagram of the S-parameters of the antenna in the "00" state according to an embodiment of the present invention;

[0041] Figure 12 This is a schematic diagram of the S-parameters of an antenna in the "10" state according to an embodiment of the present invention;

[0042] Figure 13 This is a schematic diagram of the S-parameters of the antenna in the "01" state according to an embodiment of the present invention;

[0043] Figure 14 This is an antenna gain diagram according to an embodiment of the present invention;

[0044] Figure 15 This is a shaft ratio diagram under the "00" state according to an embodiment of the present invention;

[0045] Figure 16 This is a radiation pattern of the "00" state according to an embodiment of the present invention;

[0046] Figure 17 This is a radiation pattern of the "10" state according to an embodiment of the present invention;

[0047] Figure 18 This is a radiation pattern of the "01" state according to an embodiment of the present invention. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0049] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0050] This invention discloses a polarization-reconfigurable antenna based on substrate integrated waveguide (SIW) and surface plasmon polariton (SSPP), aiming to solve the problems of fixed polarization characteristics in traditional antennas, low gain in existing polarization-reconfigurable antennas, and limited beam scanning angle. By integrating SIW and SSPP technologies, and combining orthogonal linearly polarized antenna elements with an adjustable power divider, this antenna achieves dynamic switching of polarization modes and high-gain beam scanning capabilities, making it suitable for wireless communication, radar systems, and UAV detection.

[0051] like Figure 1As shown, the polarization reconfigurable antenna of the present invention mainly includes: two sets of orthogonally arranged 45° linearly polarized antenna elements, a power divider with a 90° phase difference, and a dielectric layer and a metal reflector for support and isolation. The linearly polarized antenna elements are constructed based on a SIW resonant cavity, and SSPP elements are formed by etching periodic 45° rectangular slots. The power divider selectively drives the two sets of antenna elements to operate by controlling the switching state of PIN diodes, thereby achieving polarization mode switching. The specific structure is as follows:

[0052] I. 45° Linearly Polarized Antenna Element

[0053] like Figure 2 and Figure 3 As shown, the 45° linearly polarized antenna element is based on a SIW resonant cavity design. Its core is an SSPP element composed of periodically arranged 45° rectangular slots, with overall dimensions of L×W=239.9×12.6mm. 2 Each modulation unit contains 18 rectangular slots arranged in an anti-symmetrical layout, that is, divided into two groups on the upper and lower sides of the longitudinal center line.

[0054] 1. Gap structure

[0055] The rectangular slots within the SIW resonant cavity are arranged in an anti-symmetrical layout: such as... Figure 2 As shown in (a), with the longitudinal center line as the boundary, the gap lengths of the upper half from left to right are h1 to h18, and the gap lengths of the lower half are arranged in the opposite order (h18 to h1), with the gap length gradually increasing from h1 to the middle h10, and then gradually decreasing to h18 (see Table 1 for specific dimensions):

[0056] Table 1. Length of rectangular gaps in the modulation structure

[0057]

[0058] in, .

[0059] Furthermore, to maintain consistency with the previous design, the gap spacing was set to ps=1mm, and the overall modulation period was P=18mm; all gaps were tilted at 45°, and the lower rectangular gap was moved by ps / 4 units in both the x and y directions, forming a shape as shown in the figure. Figure 2 The misaligned modulation structure shown in (b) optimizes the surface current distribution, enhances the slow wave characteristics of the SSPP, and improves the antenna gain.

[0060] 2. Impedance Matching Structure

[0061] Figure 3To achieve 50Ω input impedance matching, a microstrip line with a width of wm = 1.23 mm and a trapezoidal transition line with a width of w1 = 2.1 mm are placed at both ends of the antenna. The length of the microstrip line is L1 = 5 mm, and the length of the transition line is L2 = 5 mm. The bottom metal layer serves as a reflective surface, which can reduce energy radiation to the rear and improve forward radiation efficiency.

[0062] Impedance matching refers to maintaining the same impedance between the antenna input impedance and the feed line characteristic impedance (50Ω in this invention). The purpose is to reduce energy reflection and ensure that the input power is radiated by the antenna to the maximum extent. A microstrip line is a planar transmission line consisting of a metal conductor strip on a dielectric substrate and a grounded metal layer at the bottom of the substrate. It is widely used in microwave integrated circuits for transmitting high-frequency signals.

[0063] 3. Verification of polarization characteristics

[0064] like Figure 4 As shown, at a frequency of 12GHz, Figure 4 In (a), when the electric field phase is 0°, the main direction of the electric field points to +45°; Figure 4 In (b), when the phase is 180°, the electric field direction shifts by 225° (opposite to the 0° phase), indicating that the element can stably radiate +45° linearly polarized waves, which is in line with the design expectation. That is, this change in electric field direction indicates that the antenna possesses linear polarization characteristics, specifically the ability to achieve +45° linear polarization. The 180° shift in electric field direction between the two phases confirms this, meaning that the antenna can effectively generate and transmit +45° linearly polarized electromagnetic waves.

[0065] II. Design of a 90° Phase Difference Power Divider

[0066] like Figure 5 As shown, the power divider adopts a traditional T-shaped structure, mainly composed of three microstrip lines, which are connected to three ports respectively (port 1 is the input excitation terminal, and ports 2 and 3 are the output terminals). Two PIN diodes S1 and S2 are provided near port 1 to dynamically select the working port ("0" indicates cutoff, and "1" indicates conduction).

[0067] 1. Phase difference characteristics

[0068] like Figure 6 As shown, a simulation analysis was performed on the power divider when the diode state is "00", and S was calculated. 21 and S 31 The simulation results show that in the 11GHz~15GHz frequency band, the phase difference between port 2 and port 3 is stable at 90°±10°, which meets the phase control requirements of polarization reconfiguration, thus realizing the function of a power divider with a 90° phase difference.

[0069] 2. Port Control Principle

[0070] like Figure 7 As shown, surface current distribution analysis reveals:

[0071] Figure 7 As shown in (a), when both S1 and S2 are off (“00” state): the current distribution of both branches is strong, and ports 2 and 3 work simultaneously, maintaining a 90° phase difference;

[0072] Figure 7 As shown in (b), when S1 is on and S2 is off (“10” state): the current is concentrated in the lower branch, and only port 3 is working;

[0073] Figure 7 As shown in (c), when S1 is off and S2 is on (“01” state): the current is concentrated on the upper branch, and only port 2 is working.

[0074] By controlling the state of the diode, precise selection of the output port can be achieved.

[0075] III. Overall Design of Polarization Reconfigurable Antenna

[0076] like Figure 1 As shown, the polarization-reconfigurable antenna consists of two sets of 45° linearly polarized antenna elements placed in parallel and symmetrically, combined through a front-end power divider. The overall dimensions are L×W=246.9×24.1mm. 2 The remaining parameters are consistent with the aforementioned unit design. Specifically, the upper unit radiates a +45° linearly polarized wave, and the lower unit radiates a -45° linearly polarized wave. Figure 8 ).

[0077] 1. Polarization mode switching principle

[0078] like Figure 9 As shown, based on the control logic of the power divider, the switching between three polarization modes is achieved by adjusting the S1 and S2 states:

[0079] Figure 9 As shown in (a), in the "00" state (dual unit operation): the electric field direction changes with the phase 0°→90°→180°→270° in a right-handed circular polarization pattern, which meets the right-handed circular polarization condition;

[0080] Specifically, when states S1 and S2 are "00", both 45° linearly polarized antennas on the upper and lower sides can operate. When the electric field phase is 0°, the electric field is mainly concentrated on the upper side and points in the +45° direction; as the phase changes to 90°, the electric field is mainly concentrated on the lower side and points in the +135° direction; when the phase further changes to 180°, the electric field is concentrated on the upper side again, but in the opposite direction to that at 0°; finally, when the phase changes to 270°, the electric field is concentrated on the lower side, and in the opposite direction to that at 90°. This change in the direction of the electric field conforms to the conditions for right-hand circular polarization, indicating that the antenna can radiate right-hand circularly polarized waves at this time.

[0081] Figure 9 As shown in (b), in the "10" state (only the lower unit works): the electric field points to +135° when the phase is 0°, and reverses when it is 180°, radiating a -45° linearly polarized wave;

[0082] Specifically, when the states of S1 and S2 are switched to "10", the power divider selects port 3 to operate, thus activating the lower linearly polarized antenna. In this configuration, when the electric field phase is 0°, the electric field points at +135°; while when the phase is 180°, the electric field direction is opposite to that at 0°. This meets the requirement of -45° linear polarization, so the antenna behaves as a -45° linearly polarized antenna, mainly radiating electromagnetic waves with -45° linear polarization.

[0083] Figure 9 As shown in (c), in the "01" state (only the upper unit works): the electric field points to +45° when the phase is 0° and reverses when it is 180°, radiating a +45° linearly polarized wave.

[0084] Specifically, when states S1 and S2 are "01", power divider selection port 2 is operational, and the electric field of the polarized reconfigurable antenna is mainly concentrated on the upper side. In this state, when the electric field phase is 0°, the electric field points in the +45° direction; while when the phase changes to 180°, the electric field points in the +225° direction, which is opposite to the electric field distribution at 0°. This meets the requirement of +45° linear polarization, so the antenna as a whole exhibits +45° linear polarization characteristics and mainly radiates electromagnetic waves with +45° linear polarization.

[0085] 2. Beam scanning characteristics

[0086] The surface wave propagation characteristics can be tuned through a modulation structure composed of periodic rectangular slots: electromagnetic waves propagate along the periodic structure, generating continuous radiative leakage and forming a directional beam. Within the 11.5 GHz to 14.5 GHz frequency band, regardless of the polarization mode, the antenna can achieve a beam scanning angle of approximately 43°. Figure 15 ).

[0087] IV. Performance Testing and Verification

[0088] 1. Test conditions

[0089] like Figure 10 As shown, the antenna sample uses three standard 50Ω SMA ports, and the dielectric substrate is Rogers 3003 (thickness 0.51mm, ε). r =3, loss tangent (0.001), and the radiation characteristics were verified by a microwave anechoic chamber testing system.

[0090] 2. Key performance indicators

[0091] S-parameters: such as Figures 11-13 As shown, in the 11.5GHz~14.5GHz frequency band, S under three states 11 All values ​​are ≤-10dB, indicating high energy radiation efficiency;

[0092] Specifically, in the "00" state, from Figure 11 As can be seen from this, the antenna's S 11 The signal remained below -10dB throughout the 11.5–14.5 GHz frequency band, indicating high energy radiation efficiency of the antenna within this band. When the frequency exceeds 13.5 GHz, S... 21 and S 31 The parameters are also below -10dB, which means that there is significant energy leakage in the structure, resulting in a reduction in the energy reaching the two ports. It is worth noting that, under these conditions, the simulation results and experimental test results of the antenna show significant consistency.

[0093] Next, for the "10" state, such as Figure 12 As shown, the S11 value of the antenna remains less than -10dB throughout the entire display frequency band. At this time, S... 21 The value is very low, in stark contrast to S. 31 The relatively high value indicates that, under these conditions, energy transfer is primarily accomplished through the lower -45° linearly polarized antenna. However, as the antenna's operating frequency gradually increases, the experimental test results of the antenna's S-parameters begin to deviate from the simulation results. Nevertheless, the two still maintain a certain degree of agreement overall, and this deviation is caused by high-frequency interference.

[0094] In the "01" state, such as Figure 13 As shown, S 11 Still below -10dB, S 21 It displays a higher value, while S 31The values ​​are lower, which means that energy transmission is mainly concentrated on the upper +45° linearly polarized antenna. In this state, the comparison between the experimental test results and the simulation results is similar to that in state "10". As the frequency increases, the degree to which the experimental test results deviate from the simulation results gradually increases, but overall they remain consistent.

[0095] Gain: such as Figure 14 As shown, the gain across the entire frequency band exceeds 10 dBi, and the gain at 12.9 GHz reaches 14.7 dBi in the "00" state;

[0096] Specifically, within the 11.5–14.5 GHz frequency band, the proposed antenna achieves a gain exceeding 10 dBi regardless of the diode's state. This outstanding performance fully demonstrates the antenna's excellent gain performance across the entire specified frequency band. In the "00" state, the antenna achieves the maximum gain of 14.7 dBi at 12.9 GHz, the highest among the three diode states.

[0097] Shaft ratio: such as Figure 15 As shown, in the "00" state, the axial ratio within the 11.5GHz~14.5GHz frequency band is ≤3dB, which meets the circular polarization requirement;

[0098] Specifically, in the "00" state, the antenna's axial ratio remains below 3dB within the 11.5~14.5GHz frequency band. This characteristic indicates that the antenna meets the relevant requirements for circular polarization and can efficiently and effectively transmit circularly polarized electromagnetic waves.

[0099] Radiation pattern (a graph describing the distribution of radiation intensity (gain) of an antenna in different directions in space, usually represented by polar or rectangular coordinates, divided into E-plane (plane containing the electric field direction) and H-plane (plane containing the magnetic field direction) radiation patterns): such as Figures 16-18 As shown, the experimental results are in high agreement with the simulation results, the main lobe is highly directional and the side lobe level is low, verifying the high gain and stable radiation characteristics.

[0100] Specifically, the radiation characteristics of the antenna were experimentally verified using a microwave anechoic chamber testing system, and the corresponding measurement data are as follows: Figures 16-18The figures (representing "00", "10", and "01" states respectively) show that the experimental results exhibit a larger sidelobe level compared to the simulation data, which may be due to the SMA port or PIN diode soldering process. Nevertheless, the experimental results generally maintain a high degree of consistency with the simulation results. The antenna employs a SIW-SSPP structure, giving it frequency beam scanning capability. Throughout the entire operating frequency band of 11.5–14.5 GHz, the antenna maintains a scanning angle of approximately 43° regardless of the diode's state. Furthermore, the antenna's radiation characteristics show significant consistency, which meets a key requirement for polarization-reconfigurable antennas. In conclusion, this antenna demonstrates excellent radiation performance, validating the effectiveness and reliability of its design.

[0101] In summary, this invention, through the collaborative design of SIW and SSPP technologies, combined with orthogonal polarization units and adjustable power dividers, achieves high gain, wide beam scanning, and flexible polarization reconfiguration, which can meet the high-performance requirements of wireless communication, radar systems, and UAV detection.

[0102] The parts of this invention not described in detail are prior art, therefore they are not described in detail here.

[0103] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0104] Although this document uses a considerable amount of technical terminology, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.

[0105] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes made to their shape or structure, any technical solution that is the same as or similar to this invention falls within the protection scope of this invention.

Claims

1. A polarization-reconfigurable antenna based on a substrate integrated waveguide and artificial surface plasmon polaritons, characterized in that, include: Two sets of orthogonally arranged linearly polarized antenna elements, each set of linearly polarized antenna elements is constructed based on a substrate integrated waveguide resonant cavity. The substrate integrated waveguide resonant cavity is provided with periodically arranged 45° rectangular slots. The rectangular slots are combined to form an artificial surface plasmon polariton unit. A power divider connected to the two sets of linearly polarized antenna elements, the power divider having an input port and two output ports, the two output ports being connected one-to-one with the two sets of linearly polarized antenna elements respectively, and the two output ports having a 90° phase difference; The power divider is equipped with at least two PIN diodes. By controlling the switching state of the PIN diodes, the output port is selectively activated to drive the corresponding linearly polarized antenna unit to work, thereby realizing the switching of polarization modes. The periodically arranged rectangular slits form a periodic modulation structure, which is used to regulate the surface wave propagation characteristics to achieve beam scanning.

2. The polarization reconfigurable antenna according to claim 1, characterized in that, The rectangular slots are arranged in an anti-symmetrical manner within the substrate integrated waveguide resonant cavity, with the longitudinal centerline of the substrate integrated waveguide resonant cavity as the boundary, and the lengths of the rectangular slots on the upper and lower sides changing symmetrically.

3. The polarization reconfigurable antenna according to claim 2, characterized in that, The rectangular gaps on both sides of the longitudinal center line are staggered along the x and y directions.

4. The polarization reconfigurable antenna according to claim 1, characterized in that, The power divider has a T-shaped structure, including one input port and two output ports, with the PIN diode positioned near the input port.

5. The polarization reconfigurable antenna according to claim 1, characterized in that, The two sets of linearly polarized antenna elements are arranged in parallel and symmetrically, with one set used to radiate +45° linearly polarized waves and the other set used to radiate -45° linearly polarized waves.

6. The polarization reconfigurable antenna according to claim 1, characterized in that, The polarization modes include +45° linear polarization, -45° linear polarization, and right-hand circular polarization; When both PIN diodes are in the off state, the two sets of linearly polarized antenna elements work simultaneously to generate a right-hand circularly polarized wave. When only one of the PIN diodes is turned on, the corresponding set of linearly polarized antenna elements will operate, generating either a +45° linearly polarized wave or a -45° linearly polarized wave.

7. The polarization reconfigurable antenna according to claim 1, characterized in that, The linearly polarized antenna unit also includes a microstrip line and a trapezoidal transition line. The microstrip line is used to achieve 50Ω input impedance matching, and the trapezoidal transition line is used to optimize the impedance matching effect.

8. The polarization reconfigurable antenna according to any one of claims 1-7, characterized in that, The back of the linearly polarized antenna element is provided with a metal reflective surface.

9. The polarization reconfigurable antenna according to any one of claims 1-7, characterized in that, The period of the periodic modulation structure is a preset value, and the spacing of the rectangular slits is a preset fixed value.

10. The polarization reconfigurable antenna according to any one of claims 1-7, characterized in that, It is made using a dielectric substrate with a preset relative permittivity and a preset thickness.

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