A loaded csrr double-layer siw polarization-adjustable antenna and a design method thereof

Abstract

The application discloses a kind of loading CSRR double-layer SIW polarization adjustable antennas, it is characterized in that, including: upper metal layer, upper dielectric substrate, intermediate metal layer, adhesive layer, lower dielectric substrate, bottom metal layer, compensation type open resonant ring, several metallized through holes, co-planar waveguide and microstrip line;Compensation type open resonant ring is etched on upper metal layer;Upper metal layer is arranged on the upper surface of upper dielectric substrate;Intermediate metal layer is arranged on the lower surface of upper dielectric substrate, and is connected with adhesive layer;Adhesive layer is also connected with the upper surface of lower dielectric substrate;Bottom metal layer is arranged on the lower surface of lower dielectric substrate;Co-planar waveguide and microstrip line constitute co-planar waveguide-microstrip line integrated feed system;Each port of SIW polarization adjustable antenna uses co-planar waveguide-microstrip line integrated feed system.

Description

Technical Field

[0001] This invention belongs to the field of communication antenna technology, specifically relating to a loaded CSRR dual-layer SIW polarized adjustable antenna and its design method. Background Technology

[0002] With the rapid development of wireless communication technology, modern communication terminal equipment is evolving towards high integration and multi-functionality. In this development process, the miniaturization design of radio frequency (RF) front-end modules has become a key breakthrough. Among these, filters and antennas, as two core components of RF systems, have seen their integrated design become an important research direction. The main function of filters is to achieve frequency band selection and effectively suppress out-of-band interference; while antennas play a crucial role in electromagnetic wave radiation and reception. The synergistic optimization of these two components is decisive for improving the overall system performance.

[0003] Meanwhile, the contradiction between the increasing number of communication protocol standards and limited spectrum resources is becoming increasingly prominent. Different application scenarios place differentiated demands on equipment: some devices need to focus on high-performance operation in specific frequency bands, while others need multi-band compatibility to adapt to complex communication environments. This differentiation in demands has led to a development trend in RF device design that emphasizes both specialization and multifunctionality. Against this backdrop, filtered antenna technology, by organically integrating frequency selection functionality with radiation characteristics, provides an innovative solution for achieving high-performance, miniaturized RF front-ends, and its research value and application prospects have attracted much attention from the industry. Summary of the Invention

[0004] This invention aims to address the shortcomings of existing technologies and provides the following solutions: A CSRR-loaded dual-layer SIW polarization-tunable antenna includes: an upper metal layer, an upper dielectric substrate, an intermediate metal layer, an adhesive layer, a lower dielectric substrate, a bottom metal layer, a compensated open resonant ring, several metallized vias, a coplanar waveguide, and a microstrip line. The compensated open resonant ring is etched onto the upper metal layer; The upper metal layer is disposed on the upper surface of the upper dielectric substrate; The intermediate metal layer is disposed on the lower surface of the upper dielectric substrate and is connected to the adhesive layer; The adhesive layer is also connected to the upper surface of the lower dielectric substrate; The bottom metal layer is disposed on the lower surface of the lower dielectric substrate; The coplanar waveguide and the microstrip line constitute a coplanar waveguide-microstrip line integrated power supply system; Each port of the SIW polarization-tunable antenna employs the coplanar waveguide-microstrip line integrated feed system.

[0005] Preferably, both the upper dielectric substrate and the lower dielectric substrate have lengths and widths of [missing information]. a 3=33mm, height is h Rogers RT / duroid 5880 dielectric substrate with a diameter of 1=0.508mm; The side length of the upper metal layer is a 3=33mm thickness is h 0 = 0.018 mm; The gap width of the compensated open resonant ring is wslot =0.5mm; The radiating patch is surrounded by an annular gap with an equivalent side length of... a A central rectangular metal area with a diameter of 1 = 18.6 mm; The feeding system comprises two L-shaped coplanar waveguide branches, the parameters of which are: L 1 = 2.6 mm; L 2 = 5.2mm, w 1 = 1mm and wL =0.3mm; The intermediate metal layer is made of Prepreg material and has dimensions of [missing information - likely dimensions]. a 3=33mm high is h A 0.1mm adhesive layer and a square metal layer; Diameter d A coupling circular hole with a diameter of 0=4.1mm is located at the center of the metal layer, and several holes with a diameter of 0 are also present. d 1=0.6mm metallized through-hole spacing between adjacent through-holes is w 0 = 0.8 mm.

[0006] Preferably, the SIW polarization adjustable antenna adopts a dual-port feeding design, with each port equipped with the coplanar waveguide-microstrip line integrated feeding system, and the resistance of the coplanar waveguide-microstrip line integrated feeding system is 50Ω.

[0007] Preferably, the dielectric constant of the materials of the upper dielectric substrate and the lower dielectric substrate is 2.2.

[0008] Preferably, the distance from the groove to the center of the cavity a 1 = 18.6 mm, SIW cavity side length a 2 = 26mm, total side length of the substrate a 3=33mm, diameter of metallized through hole d 1 = 0.6mm, through-hole spacing w 0 = 0.8mm, microstrip feed line width w 1 = 1mm L Length of coplanar waveguide branchesL 1 = 2.6 mm and L 2 = 5.2mm, width of the annular gap wopen =0.2mm, gap width wslot =0.5mm, L Type branch width wL =0.3mm, metal layer thickness h 0 = 0.018 mm, thickness of the dielectric substrate h 1 = 0.508 mm, adhesive layer thickness h 2 =0.1mm.

[0009] This invention also provides a design method for a loaded CSRR dual-layer SIW polarized tunable antenna, the method being used to design the aforementioned antenna, comprising the following steps: Based on the target frequency band requirements, the SIW waveguide width is determined using the TE10 mode cutoff frequency formula. A gradient SIW-microstrip conversion structure was designed, and after parameter optimization, a good match with insertion loss <0.5dB was achieved in the operating frequency band. Calculate the coupling coefficient between each cavity and the external Q value of the input and output based on the Chebyshev response characteristics; The coupling window and each cavity sub-model were established using HFSS software. The size of each sub-model was determined by parameter scanning. Then, the sub-models were integrated and jointly optimized to complete the design of the SIW polarization tunable antenna.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention achieves excellent filtering performance at a center frequency of 5.7 GHz through an out-of-plane capacitive coupling structure, with measured out-of-band rejection better than 35 dB. The antenna of this invention features polarization reconfigurability, allowing for flexible switching of operating modes by controlling the dual-port excitation method: linear polarization radiation (maximum gain 7.28 dBi) is achieved with single-port excitation, while circular polarization radiation (maximum gain 7.23 dBi, axial ratio 2.2 dB) is achieved with dual-port equal-amplitude out-of-phase excitation. Attached Figure Description

[0011] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the antenna structure according to an embodiment of the present invention, wherein (a) is a top view and (b) is a side view; Figure 2This is a SIW filter structure according to an embodiment of the present invention; Figure 3 This is the equivalent circuit diagram of the SIW antenna after CSRR loading in an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the effect of the distance from the slot to the center of the cavity on the return loss according to an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the effect of the gap width on return loss and return loss according to an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the effect of the slit opening width on the distribution according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the S-parameters of the filter and the filter antenna (operating in circular polarization state) according to an embodiment of the present invention, wherein (a) is the S-parameter characteristics of the filter and (b) is the S-parameter characteristics of the filter antenna. Figure 8 This is a schematic diagram of the radiation direction of an embodiment of the present invention, wherein (a) is a single-port feed and (b) is a dual-port feed; Figure 9 This is a schematic diagram of the surface current distribution characteristics of the antenna under different feeding conditions according to an embodiment of the present invention, wherein (a) is single-port feeding and (b) is dual-port feeding; Figure 10 This is a simulated axial ratio diagram of the left-hand circularly polarized antenna in the z-direction within the bandwidth of an embodiment of the present invention. Detailed Implementation

[0013] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] Example 1 In this embodiment, as Figure 1 As shown, a CSRR-loaded dual-layer SIW polarization-tunable antenna includes: an upper metal layer, an upper dielectric substrate, an intermediate metal layer, an adhesive layer, a lower dielectric substrate, a bottom metal layer, a compensated open resonant ring, several metallized vias, a coplanar waveguide, and a microstrip line.

[0016] A compensated open-ring resonator is etched on the upper metal layer; the upper metal layer is disposed on the upper surface of the upper dielectric substrate; the middle metal layer is disposed on the lower surface of the upper dielectric substrate and connected to the adhesive layer; the adhesive layer is also connected to the upper surface of the lower dielectric substrate; the bottom metal layer is disposed on the lower surface of the lower dielectric substrate; the coplanar waveguide and microstrip line constitute a coplanar waveguide-microstrip line integrated feeding system; each port of the SIW polarization tunable antenna adopts a coplanar waveguide-microstrip line integrated feeding system.

[0017] Both the upper and lower dielectric substrates are made of materials with dimensions of [missing information]. a 3=33mm, height is h Rogers RT / duroid 5880 dielectric substrate with a thickness of 1=0.508mm; the side length of the upper metal layer is... a 3=33mm thickness is h 0 = 0.018 mm; the gap width of the compensated open-circuit resonator is wslot =0.5mm; the radiating patch is surrounded by an annular gap with an equivalent side length of... a A central rectangular metal region with a diameter of 1 = 18.6 mm; the feeding system includes two L-shaped coplanar waveguide branches, the parameters of which are: L 1 = 2.6 mm; L 2 = 5.2mm, w 1 = 1mm and wL =0.3mm; the intermediate metal layer is made of Prepreg material with length and width of [missing information]. a 3=33mm high is h A 0.1mm thick adhesive layer and a square metal layer; diameter is... d A coupling circular hole with a diameter of 0=4.1mm is located at the center of the metal layer, and several holes with a diameter of 0 are also present. d 1=0.6mm metallized through-hole spacing between adjacent through-holes is w 0 = 0.8 mm.

[0018] The SIW polarization tunable antenna adopts a dual-port feeding design, with each port equipped with a coplanar waveguide-microstrip line integrated feeding system, the resistance of which is 50Ω.

[0019] The dielectric constant of the materials of the upper and lower dielectric substrates is 2.2.

[0020] Distance from the groove to the center of the cavity a 1 = 18.6 mm, SIW cavity side length a 2 = 26mm, total side length of the substrate a 3=33mm, diameter of metallized through hole d 1 = 0.6mm, through-hole spacing w0 = 0.8mm, microstrip feed line width w 1 = 1mm L Length of coplanar waveguide branches L 1 = 2.6 mm and L 2 = 5.2mm, width of the annular gap wopen =0.2mm, gap width wslot =0.5mm, L Type branch width wL =0.3mm, metal layer thickness h 0 = 0.018 mm, thickness of the dielectric substrate h 1 = 0.508 mm, adhesive layer thickness h 2 =0.1mm.

[0021] Example 2 In this embodiment, a design method for a CSRR dual-layer SIW polarized tunable antenna includes the following steps: Based on the target frequency band requirements, the SIW waveguide width was determined using the TE10 mode cutoff frequency formula. A gradient SIW-microstrip conversion structure was designed, and after parameter optimization, a good match with insertion loss <0.5dB was achieved in the operating frequency band. The coupling coefficient between each cavity and the external Q value of the input and output were calculated based on the Chebyshev response characteristics. Sub-models of the coupling window and each cavity were established using HFSS software. The size of each sub-model was determined by parameter scanning. Then, the sub-models were integrated and jointly optimized to complete the design of the SIW polarization tunable antenna.

[0022] Specifically, this paper first presents a design example of a SIW bandpass filter operating at a center frequency of 5.8 GHz. This filter utilizes Chebyshev response characteristics and features a 170 MHz passband bandwidth and 0.5 dB in-band ripple. The design innovatively employs a metallized via array for electromagnetic coupling and achieves a compact layout through optimized transition structures. The design process mainly consists of three steps: 1. Based on coupled resonance theory, the required coupling coefficient is calculated. k = 0.0299 and external quality factor Qe =25.16. These parameters are achieved through a carefully designed circular coupling hole (diameter...). d =4.1mm, spacing s =0.6mm). Secondly, using a substrate material with a dielectric constant of 2.65 and a thickness of 1mm, the coupling coefficient matrix extracted from the design of a coplanar waveguide-SIW transition structure with a microstrip line width of 2.9mm is as follows: Where M represents the coupling coefficient matrix.

[0023] 2. The single-cavity substrate uses a substrate material with a dielectric constant of 2.65 and a thickness of 1 mm. For example... Figure 2 As shown, the structural design includes the following key dimensional parameters: metallized via diameter 4.1 mm, center-to-center spacing between adjacent vias 0.6 mm, and microstrip transmission line width 2.9 mm. The transition between the microstrip line and the SIW is achieved using a coplanar waveguide transition, resulting in a more compact size.

[0024] 3. In the study of dual-cavity coupling characteristics, a significant mode splitting phenomenon can be observed through electromagnetic field simulation. When two SIW resonators couple, their resonance characteristics change significantly, specifically, the original single resonance peak splits into two characteristic peaks. By adjusting the size and position of the coupling window between the resonators, the coupling coefficient can be precisely controlled, thereby obtaining the desired filter frequency response characteristics. The coupling coefficient between the two SIW cavities... k The following formula can be used to obtain the scattering parameter curve: Among them, f e Indicates the high-frequency resonant point. fm This indicates the resonant point at a low frequency.

[0025] Subsequently, an SIW slot antenna was designed using an SIW bandpass filter.

[0026] A compensated split-ring resonator (CSRR) is etched onto the upper metal surface. The CSRR structure can be modeled as a parallel LC resonant circuit, which, as the terminating resonant unit, can effectively radiate electromagnetic waves. The equivalent inductance L of this structure mainly depends on the perimeter of the resonant ring, while the equivalent capacitance C is mainly determined by the width of the opening gap in the resonant ring. The equivalent model of the SIW antenna after loading the CSRR is as follows: Figure 3 As shown. Y0 represents the admittance of the input / output feed line, which represents the antenna's feed system. In a 50Ω standard impedance system, its value is typically 1 / 50 = 0.02S. Lr1 and Cr1 represent the equivalent inductance and equivalent capacitance of the first SIW resonant cavity, which together determine the intrinsic resonant frequency of the first cavity layer. Lr1 and Cr1 represent the equivalent inductance and equivalent capacitance of the second SIW resonant cavity, corresponding to the second resonant space in the structure. Cm represents the equivalent coupling capacitance between cavities, corresponding to the "capacitive coupling" box in the figure. It is achieved through the central circular hole (diameter of...) on the intermediate metal plate. d The π-type network (containing a series Cm and a parallel -Cm) is used to control the energy exchange intensity between the two cavities (0=4.1mm) to accurately simulate this capacitive coupling effect. La and Ca represent the equivalent inductance and equivalent capacitance of the CSRR (annular gap), where La is mainly determined by the perimeter of the annular gap (given by parameters). a1. Determined by (Ca), which is mainly determined by the gap width ( wslot ) and opening gap width ( wopen or lopen )Decide.

[0027] Figure 1 The structure of the designed polarization-tuned SIW slot antenna is demonstrated. This antenna employs a dual-port feed design, with each port using a 50Ω coplanar waveguide-microstrip line integrated feed system. The seamless connection between the coplanar waveguide and the microstrip line achieves high compatibility with planar circuit systems. Furthermore, by optimizing key parameters such as feed line width and slot length, impedance matching characteristics are optimized in the 5.8GHz operating frequency band. Finally, the dual orthogonal feed structure supports controllable switching between left-hand and right-hand circularly polarized waves.

[0028] Through parameter scanning analysis, it was found that, for example Figure 4 As shown, when the side length parameter of the CSRR structure a As 1 increases, while keeping other geometric parameters constant, the bandgap characteristics exhibit a regular change. With... a 1. Increasing the bandgap center frequency from 3mm to 5mm decreases. This phenomenon can be explained from the perspective of the equivalent circuit: the increase in side length leads to an increase in the equivalent inductance of the resonant ring, which in turn leads to a decrease in the resonant frequency of the equivalent circuit, thus shifting the bandgap center frequency to lower frequencies.

[0029] After determining the cavity size and slot length, another key parameter affecting the resonant frequency is the slot width. Figure 5 In this context, the slot width is denoted by wslot. Within a suitable range, keeping other parameters constant, increasing the slot width of the CSRR structure reduces the equivalent inductance, thereby increasing the bandgap center frequency. This characteristic allows for effective control of the resonant frequency by adjusting the slot width. Simultaneously, the increased slot width enhances the blocking effect on surface currents, thus improving the isolation between the two ports. However, higher port isolation results in less crosstalk between the ports and makes it easier to excite circular polarization.

[0030] After determining the width and length of the slot, the gap length of the CSRR also needs to be adjusted. It can be observed that a larger gap length reduces the isolation between the two ends. Figure 6 Chinese lopen This indicates that, keeping other parameters constant, the opening width of the CSRR... lopen As the CSRR aperture width gradually increases, the equivalent capacitance decreases, thereby increasing the bandgap center frequency.

[0031] Further fine-tuning was performed on other parameters, such as the length of the L-shaped coplanar waveguide stub and the diameter of the cavity metallized via, to achieve a better 50-ohm impedance matching effect. The final parameters are given in Table 1.

[0032] Table 1 .

[0033] Example 3 In this embodiment, the designed SIW slot antenna is simulated.

[0034] This dual-polarized antenna employs a dual-port fed structure design. Optimized isolation ensures that electromagnetic energy is primarily radiated into free space through the radiating slots, rather than directly transmitted between the ports. To achieve this characteristic, substrate integrated waveguide (SIW) technology is used. Excitation in TE101 mode creates a specific current distribution on the resonant cavity surface: flowing from the first half-wavenumber region to the second half-wavenumber region. The antenna uses Rogers RT / Duroid 5880 material with a dielectric constant of 2.2, a loss tangent of 0.0009, and a substrate thickness of 0.508 mm as the dielectric substrate. The metallized via array is designed with a diameter of 0.6 mm and a spacing of 0.9 mm, maintaining structural compactness while ensuring electromagnetic shielding. The design process first determines the initial dimensions of the resonant cavity and coupling structure based on theoretical calculations, and then uses HFSS software to build a three-dimensional electromagnetic model for precise simulation optimization.

[0035] Figure 7 These are the S-parameters of the filter and the filtered antenna (operating in circular polarization). (From...) Figure 7 From (a), we can see that the center frequency of the simulated filter is 5.6 GHz. The return loss is 15.38 dB. The insertion loss is 1 dB. The bandwidth is 170 MHz. The antenna operating frequency can be freely designed within the passband. Figure 7 As shown in (b), the simulated center frequency of S11 in the dual-port power supply is 5.7 GHz and its value is 15.38 dB. Its transmission coefficient S21 represents the isolation between the two ports, which is 17 dB, indicating good isolation.

[0036] Figure 8 This is a simulated radiation pattern of the antenna within the frequency band. Figure 8 In (a), when the power is supplied from a single port, Figure 8 In diagram (b), when the power supply is dual-port, the maximum gains are 7.28 dBi and 7.2 dBi, respectively. This indicates that energy can be effectively radiated into free space.

[0037] Figure 9 The surface current distribution characteristics of the antenna under different feeding conditions are demonstrated. In single-port excitation mode, when only port 1 is fed and port 2 is connected to a 50Ω matched load, the metal surface forms a current distribution as shown in the diagram. Figure 9The y-direction linear polarization current distribution is shown in (a). This symmetrical structural design allows the current distribution to rotate 90° accordingly when the excitation conditions are interchanged (port 2 is fed, port 1 is matched), generating x-direction linear polarization radiation. In the dual-port circular polarization operating mode, the equal-amplitude, out-of-phase (90° phase difference) excitation of the two orthogonal ports produces a composite current distribution, such as... Figure 9 As shown in (b), its characteristic is a spiral current distribution along the diagonal direction, which is formed by the superposition of two orthogonal current vectors. This reconfigurable current distribution mechanism enables the antenna to flexibly switch between x / y linear polarization and circular polarization.

[0038] Figure 10 The axial ratio frequency response characteristics of a left-hand circularly polarized antenna in the z-axis direction are demonstrated. Simulation results show that within the designed operating frequency band of 5.5-5.9 GHz, the antenna maintains good circular polarization characteristics in the direction of maximum radiation. In particular, at the center frequency of 5.7 GHz, the antenna's normal axial ratio reaches the optimal value of 2.6 dB, meeting the requirements of engineering applications. The circular polarization performance of this antenna stems from its special radiating structure design, achieving stable rotational characteristics by precisely controlling the 90° phase difference between the two orthogonal ports. Notably, the right-hand circularly polarized mode is achieved through an opposite phase excitation relationship, and its axial ratio and frequency response characteristics are symmetrical to those of the left-hand circularly polarized mode.

[0039] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A CSRR-loaded dual-layer SIW polarization-tunable antenna, characterized in that, include: Upper metal layer, upper dielectric substrate, middle metal layer, adhesive layer, lower dielectric substrate, bottom metal layer, compensated open resonant ring, several metallized vias, coplanar waveguide and microstrip line; The compensated open resonant ring is etched onto the upper metal layer; The upper metal layer is disposed on the upper surface of the upper dielectric substrate; The intermediate metal layer is disposed on the lower surface of the upper dielectric substrate and is connected to the adhesive layer; The adhesive layer is also connected to the upper surface of the lower dielectric substrate; The bottom metal layer is disposed on the lower surface of the lower dielectric substrate; The coplanar waveguide and the microstrip line constitute a coplanar waveguide-microstrip line integrated power supply system; Each port of the SIW polarization-tunable antenna employs the coplanar waveguide-microstrip line integrated feed system.

2. The loaded CSRR dual-layer SIW polarization adjustable antenna according to claim 1, characterized in that, Both the upper dielectric substrate and the lower dielectric substrate have lengths and widths of [missing information]. a 3=33mm, height is h Rogers RT / duroid5880 dielectric substrate with a thickness of 1=0.508mm; The side length of the upper metal layer is a 3=33mm thickness is h 0 = 0.018 mm; The gap width of the compensated open resonant ring is wslot =0.5mm; The radiating patch is surrounded by an annular gap with an equivalent side length of... a A central rectangular metal area with a diameter of 1 = 18.6 mm; The feeding system comprises two L-shaped coplanar waveguide branches, the parameters of which are: L 1 = 2.6 mm; L 2 = 5.2mm, w 1 = 1mm and wL =0.3mm; The intermediate metal layer is made of Prepreg material and has dimensions of [missing information]. a 3=33mm high is h A 0.1mm adhesive layer and a square metal layer; Diameter d A coupling circular hole with a diameter of 0=4.1mm is located at the center of the metal layer, and several holes with a diameter of... d 1=0.6mm metallized through-hole spacing between adjacent through-holes is w 0 = 0.8 mm.

3. The loaded CSRR dual-layer SIW polarization adjustable antenna according to claim 1, characterized in that, The SIW polarization-tunable antenna adopts a dual-port feeding design, with each port equipped with the coplanar waveguide-microstrip line integrated feeding system, the resistance of which is 50Ω.

4. The loaded CSRR dual-layer SIW polarized adjustable antenna according to claim 1, characterized in that, The dielectric constant of the materials of the upper dielectric substrate and the lower dielectric substrate is 2.

2.

5. The loaded CSRR dual-layer SIW polarization adjustable antenna according to claim 1, characterized in that, Distance from the groove to the center of the cavity a 1 = 18.6 mm, SIW cavity side length a 2 = 26mm, total side length of the substrate a 3=33mm, diameter of metallized through hole d 1 = 0.6mm, through-hole spacing w 0 = 0.8mm, microstrip feed line width w 1 = 1mm L Length of coplanar waveguide branches L 1 = 2.6 mm and L 2 = 5.2mm, width of the annular gap wopen =0.2mm, gap width wslot =0.5mm, L Type branch width wL =0.3mm, metal layer thickness h 0 = 0.018 mm, substrate thickness h 1 = 0.508 mm, adhesive layer thickness h 2 =0.1mm.

6. A design method for a loaded CSRR dual-layer SIW polarized tunable antenna, the method being used to design the antenna according to any one of claims 1-5, characterized in that, Includes the following steps: Based on the target frequency band requirements, the SIW waveguide width is determined using the TE10 mode cutoff frequency formula. A gradient SIW-microstrip conversion structure was designed, and after parameter optimization, a good match with insertion loss <0.5dB was achieved in the operating frequency band. Calculate the coupling coefficient between each cavity and the external Q value of the input and output based on the Chebyshev response characteristics; The coupling window and each cavity sub-model were established using HFSS software. The size of each sub-model was determined by parameter scanning. Then, the sub-models were integrated and jointly optimized to complete the design of the SIW polarization tunable antenna.

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