High-order mode based fsiw millimeter wave microstrip antenna

Abstract

The application discloses a kind of FSIW millimeter wave microstrip antennas based on high-order mode, including multiple periodic array distribution antenna module;Each antenna module is 2x2 antenna array, including antenna radiation structure, two FSIW cavity structure, Y-type waveguide power divider.Antenna radiation structure includes antenna radiation unit, first dielectric layer, first metal layer;Antenna radiation unit includes four metal rectangular patches.Wherein, metal rectangular patch is used as antenna unit to radiate outward, and a group of symmetric coupling feed slots is etched on the two sides directly below each unit, which is used by high-order mode TE 20 mode;FSIW cavity for conducting TE 20 Mode is formed by folding inward on both sides through ideal magnetic wall surface, reducing nearly 33% of the plane area.The antenna of the application obtains 8.93% impedance bandwidth, lower than 13.4dB side lobe level and 12.85dBi maximum peak gain, and can be directly integrated with millimeter wave radio frequency front-end circuit.

Description

Technical Field

[0001] This invention belongs to the field of microwave antenna technology, specifically relating to a millimeter-wave microstrip antenna based on high-order mode FSIW (folded substrate integrated waveguide), which can be applied to 5G mobile communication and satellite fields, etc. Background Technology

[0002] As modern wireless communication technology continues to advance, the requirements for the performance and integration of wireless communication systems are becoming increasingly stringent, and the requirements for antennas, as a part of the system, are also increasing accordingly.

[0003] Substrate integrated waveguides (SIWs) are widely researched and applied in microwave devices such as filters, phase shifters, couplers, power dividers, and antennas due to their low loss, low profile, and ease of fabrication. However, traditional SIWs are relatively large, often failing to meet the miniaturization requirements of modern microwave circuits. The introduction of half-mode SIWs (HSIWs) has achieved a considerable miniaturization effect in terms of planar size, approaching half the original area, while offering similar transmission performance. However, because one side is open, energy leakage is relatively high, making it unsuitable for building antenna radiation structures on the non-open side.

[0004] On the other hand, higher-order mode antennas have been widely used to improve antenna gain. Microstrip antennas are easy to fabricate, readily integrated into planar circuits, and offer advantages such as small size, low profile, and low cost. Microstrip antennas utilizing higher harmonic radiation allow for larger resonant element sizes, increasing element gain and reducing the need for a feed network to achieve high gain, while also lowering fabrication difficulty. Applying substrate-integrated waveguides to higher-order mode microstrip antennas can effectively improve their anti-interference capabilities. However, when assembling antenna arrays using substrate-integrated waveguides, their larger size often leads to problems such as larger spacing between higher-order mode antenna elements and higher sidelobe levels.

[0005] To address the aforementioned issues, this invention proposes a microstrip antenna array based on a folded substrate integrated waveguide with higher-order modes. In the higher-order modes, folding of the higher-order modes is achieved using FSIW, resulting in a size reduction of over 33%. As a narrowband antenna, it has an impedance bandwidth of 8.93% and a maximum peak gain of 12.85 dBi. Furthermore, the area reduction allows for closer spacing between antenna elements, thereby reducing the high sidelobe level. In this invention, the highest sidelobe level peak is below 13.4 dB. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of large size of traditional SIW and high sidelobe level in antennas using SIW structures, and to provide a high-order mode-based FSIW millimeter-wave microstrip antenna.

[0007] The present invention adopts the following technical solution:

[0008] A folded substrate integrated waveguide millimeter-wave microstrip antenna based on higher-order modes includes multiple periodically arrayed antenna modules; wherein,

[0009] Each antenna module is a 2×2 antenna array, including an antenna radiating structure, two FSIW cavity structures, and a Y-type waveguide power divider;

[0010] The antenna radiation structure includes an antenna radiation element, a first dielectric layer (2), and a first metal layer (3);

[0011] The antenna radiating element comprises four identical metal rectangular patches (1) arranged in a 2×2 array, with gaps between the four metal rectangular patches (1);

[0012] The first metal layer (3) is etched with four pairs of coupling feed slots (8) corresponding to the metal rectangular patch (1). That is, the projection of the four pairs of coupling feed slots (8) on the antenna radiating element falls on the four metal rectangular patches (1) respectively; the center of each metal rectangular patch (1) is aligned with the center of the corresponding coupling feed slot (8).

[0013] The coupling feed gap (8) is symmetrical about the axis of the long side (i.e., the Y-axis) of the first dielectric layer (2);

[0014] Preferably, the number of metal rectangular patches (1) distributed along the short side (i.e., the X-axis) of the rectangular coupling slot (10) of the antenna radiating element is the same as the number of metal rectangular patches (1) distributed along the long side (i.e., the Y-axis) of the rectangular coupling slot (10).

[0015] Preferably, the spacing M_x between adjacent metal rectangular patches (1) along the short side direction (i.e., the X-axis) of the rectangular coupling gap (10) is 0.5λ0 to λ0, more preferably 0.56λ0; the spacing M_y between adjacent metal rectangular patches (1) along the long side direction (i.e., the Y-axis) of the rectangular coupling gap (10) is 0.5λ0 to λ0, more preferably 0.65λ0, where λ0 is the wavelength corresponding to 28 GHz in free space;

[0016] Preferably, the width W of the metal rectangular patch (1) p Satisfying 0.28λ0, length L p To satisfy 0.20λ0, the antenna radiation is controlled to be in the millimeter-wave band;

[0017] Preferably, the width of the optimized coupling feed gap pair (8) is W. s The length Ls satisfies 0.19λ0;

[0018] The two FSIW cavity structures are symmetrically arranged about the Y-axis of the antenna module; each FSIW cavity structure includes a first metal layer (3), a second dielectric layer (4), a second metal layer (5), an intermediate metal plate disposed in the middle layer of the second dielectric layer (4), a first metallized through-hole array (9a) penetrating the second dielectric layer (4), and a second metallized blind hole array (9d);

[0019] Preferably, the distance between the centers of the two FSIW cavities is the same as the spacing between the two metal rectangular patches (1) along the X-axis;

[0020] The second metallized blind hole array (9d) constitutes the FSIW cavity electric wall formed by the overlapping of the two sides of the SIW electric wall after folding;

[0021] The first metallized through-hole array (9a) consists of two long side metal walls and two short-circuit metal walls formed by folding and closing the magnetic wall of the SIW to form the FSIW cavity;

[0022] The intermediate metal layer (9b) is formed by the folded surface of SIW. The two short-circuit metal walls surrounded by the first metallized via array (9a) penetrate the intermediate metal layer (9b). The length of the long side of the intermediate metal layer (9b) is longer than the length of the two long side metal walls surrounded by the first metallized via array (9a). This is to prevent unnecessary energy leakage from the part where the first metallized via array (9a) contacts the short-circuit end of the intermediate metal layer (9b). Also, it is close to the edge of the structure, so there is no need to design an additional length for the part of the intermediate metal layer (9b) that extends out of the short side of the first metallized via array (9a), which is convenient for processing.

[0023] The two long side metal walls of the FSIW cavity do not contact the intermediate metal layer (9b);

[0024] The second metal layer (5) is etched with two rectangular coupling gaps (10), which are located directly below the second metallized blind hole array (9d);

[0025] The length of the FSIW cavity is L. siw Width is W siw ;

[0026] Preferably, the diameters of the through holes in the first metallized via array (9a) and the second metallized blind via array (9d) are the same;

[0027] Preferably, the system also includes a side-center metal perturbation post (9c) for connecting the intermediate metal layer (9b) and the first metal layer (3), and a radiation matching metal perturbation post (9e) for connecting the intermediate metal layer (9b) and the second metal layer (5), which are used to bisect the higher-order mode and for antenna radiation matching, respectively.

[0028] Preferably, the operating bandwidth is adjusted by regulating the electric wall distance Xm formed by the edge-center metal perturbation pillar (9c) and the second metallized blind hole array (9d), and the electric wall distance Xs formed by the radiation matching metal perturbation pillar (9e) and the second metallized blind hole array (9d).

[0029] Preferably, the length L of the rectangular coupling slit (10) is... s1 For FSIW waveguide wavelength λ g One-quarter of the width of the keystone ensures that the coupling resonance is possible, and its width W is [missing information]. s1 It should be as small as possible;

[0030] The Y-type waveguide power divider adopts a one-to-two equal power divider; the projections of the two rectangular coupling slots (10) on the Y-type waveguide power divider are respectively located in the two paths equally divided by the Y-type waveguide power divider;

[0031] Preferably, the Y-type waveguide power divider includes a second metal layer (5), a third dielectric layer (6), a third metal layer (7), a third metallized via array penetrating the third dielectric layer (6), and a coupling matching metal micro-perturbation pillar (11a), a refractive micro-perturbation pillar (11b), and a central metal micro-perturbation pillar (11c).

[0032] The coupling matching metal perturbation post (11a) and the rectangular coupling slot (10) are used to couple energy from the Y-type waveguide power divider to the two FSIW cavities; the central metal perturbation post (11c) that divides the input signal energy is placed at the bifurcation position of the "Y", and the distance D between the central metal perturbation post (11c) and the input port is adjusted. xv3 The energy that will be divided will be coupled to the refractive perturbation column (11b) at the corner, and then coupled to the rectangular coupling gap (10) at 90 degrees.

[0033] Preferably, the coupling matching metal micro-perturbation pillar (11a), the refractive micro-perturbation pillar (11b), and the central metal micro-perturbation pillar (11c) have the same aperture as the first metallized through-hole array (9a);

[0034] Preferably, the first dielectric layer (2) and the third dielectric layer (6) have the same thickness, and the thickness of the second dielectric layer (4) is the sum of the thicknesses of the first dielectric layer (2) and the third dielectric layer (6).

[0035] Working principle:

[0036] The input electric field at the input terminal is TE 10The signal is split into two equal half-power signals by the central metal perturbation column (11c) in the Y-type waveguide power divider. The half-power signals are refracted to the short-circuit ends of the Y-type waveguide under the perturbation of the refraction perturbation column (11b). The signal path is similar to the shape of "Y".

[0037] The half-power signals at both ends are coupled into the FSIW cavity structure under the action of the coupling matching metal micro-perturbation pillar (11a) and the rectangular coupling slot (10) at the short-circuit end of the Y-type waveguide;

[0038] When designing the FSIW cavity structure, an appropriate bandwidth should be selected based on the designed frequency band, as shown in the following formula:

[0039]

[0040] Among them, C o d represents the speed of light, s represents the diameter of the through-hole, f represents the spacing between the through-holes, and d represents the speed of light. c (TE) 20 TE 20 The cutoff frequency of the mode;

[0041] Because after folding the SIW, the width of the metal via wall, i.e., the width of the second metallized blind via array (9d), is not equal to the width of the upper and lower layers of the FSIW. This is addressed by introducing a correction term Δ:

[0042]

[0043] Select the appropriate fold gap width W based on the value of the correction term. f ;

[0044] The length L of the rectangular coupling gap (10) s1 Based on approximately the waveguide wavelength λ g One-quarter;

[0045]

[0046] Where λ represents the wavelength of the center frequency of the selected millimeter-wave band in free space, λ c Indicates the cutoff frequency of the FSIW;

[0047] The electric field TE of the signal 10 The mode, through the coupling effect of the rectangular coupling gap (10), generates TE signals with opposite phases on both sides of the long side of the rectangular coupling gap (10). 20 The higher-order mode electric field was simulated, and then a metal micro-perturbation pillar (9c) was introduced at the center of the edge to expand the frequency bandwidth. Electromagnetic simulations were performed by moving the pillar along the X-axis at the center of the upper and lower layers of the FSIW to obtain the optimal performance position, which is located on the upper layer of the FSIW and at a distance of X from the second metallized blind hole array (9d) along the X-axis. s ;

[0048] Finally, TE 20 Under the matching effect of the radiation-matching metal perturbation pillars in the lower layer of the FSIW cavity, the electric field forms a radiation source at the coupled feed gap pair (8); TE 20 The two electric fields of the mode are out of phase and act on the rectangular coupling gap (10) in the two folded FSIW cavities, generating the same radiation field source and coupling to the metal rectangular patch (1), generating currents in the same direction. The currents are superimposed, and the metal rectangular patch (1) radiates energy outward.

[0049] The beneficial effects of this invention are as follows:

[0050] (1) This invention is the first to propose a folded substrate integrated waveguide in the field of antennas, which achieves a size reduction of more than 33% in planar effect and achieves miniaturization effect; the antenna of this invention has an impedance bandwidth of 8.93%, a sidelobe level of less than 13.4dB and a maximum peak gain of 12.85dBi, and can be directly integrated with millimeter wave RF front-end circuits.

[0051] (2) The antenna array elements of the present invention are arranged with similar longitudinal and lateral distances, which has good directivity and low sidelobe level.

[0052] (3) The antenna array input terminal of the present invention adopts a single-mode excitation and a high-order mode generation method to radiate patch antenna elements, which effectively avoids the complex high-order mode excitation method at the input terminal. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the three-dimensional layered structure of the antenna array of the present invention;

[0054] Figure 2 The following are schematic diagrams of the structure of each layer of the present invention: (a) radiation plan view, (b) antenna feed structure plan view, (c) upper layer plan view of FSIW cavity, (d) lower layer plan view of FSIW cavity, (e) cross-sectional view of FSIW cavity structure, (f) plan view of FSIW cavity feed structure, and (g) plan view of Y-type waveguide power divider.

[0055] Figure 3 These are the reflection coefficient and gain curves of the antenna array of the present invention;

[0056] Figure 4 It is the voltage standing wave ratio (VSWR) of the antenna array of the present invention;

[0057] Figure 5 This refers to the radiation efficiency of the antenna array of the present invention;

[0058] Figure 6These are the radiation patterns of the antenna array of the present invention in the E-plane and H-plane at (a) 28 GHz, (b) 29 GHz, (c) 30 GHz and (d) the maximum peak gain frequency of 29.3 GHz.

[0059] The diagram is labeled as follows: 1. Metal rectangular patch; 2. First dielectric layer; 3. First metal layer; 4. Second metal layer; 5. Third dielectric layer; 6. Third metal layer; 7. Coupled feed slot pair; 8. First metallized via array; 9a. Middle metal layer; 9b. Edge-center metal micro-perturbation pillar; 9c. Second metallized blind via array; 9d. Radiation matching metal micro-perturbation pillar; 9e. Rectangular coupling slot; 10. Coupled matching metal micro-perturbation pillar; 11a. Refractive micro-perturbation pillar; 11b. Center metal micro-perturbation pillar; 11c. Detailed Implementation

[0060] The implementation of the present invention will be further described below with reference to the accompanying drawings:

[0061] Figure 1 This is a schematic diagram of a three-dimensional layered structure of an antenna array. The 2×2 rectangular patch antenna array based on a folded substrate integrated waveguide of higher order modes provided by this invention consists of, from top to bottom, a metal rectangular patch 1, a first dielectric layer 2, a first metal layer 3, a second dielectric layer 4, an intermediate metal layer 9b embedded in the FSIW cavity of the second dielectric layer 4, a first metallized via array 9a, an intermediate metal layer 9b, a side-center metal micro-perturbation pillar 9c, a second metallized blind aperture array 9d, a radiation matching metal micro-perturbation pillar 9e, a second metal layer 5, a third dielectric layer 6, and a bottommost third metal layer 7. The dielectric layer material is Rogers RT / duroid 4003(tm) with a dielectric constant of 3.55, and the metal layer material is copper. Metal rectangular patches 1 are arranged periodically to form a 2×2 array. The energy at the input end is evenly divided by the central metal perturbation pillar 11c, and then coupled into the FSIW cavity structure by the refractive metal perturbation pillar 11b, the coupling matching metal perturbation pillar 11a, and the rectangular coupling gap 10, thus forming the power supply process from the splitter to the cavity. The energy entering the cavity forms a TE due to the coupling power supply method of the rectangular coupling gap 10 and the energy separation effect of the side-center perturbation metal pillar 9c. 10 Model to TE 20 The mode transition; then, the radiation field source generated by the higher-order mode electric field of the FSIW cavity through the coupling feed gap is used as the feed power source for the antenna array.

[0062] Figure 2 Plan view of each layer of the antenna array structure: Figure 2 (a) is a radial planar diagram. Figure 2 (b) is a plan view of the antenna feeding structure. Figure 2 (c) is a plan view of the upper layer of the FSIW cavity. Figure 2(d) is a plan view of the lower layer of the FSIW cavity. Figure 2 (e) is a cross-sectional view of the FSIW cavity structure. Figure 2 (f) is a plan view of the FSIW cavity power supply structure. Figure 2 (g) is a plan view of the Y-type waveguide power divider.

[0063] like Figure 2 As shown in (a), the length and width of the microstrip rectangular patch are L and L, respectively. p W p The spacing between the patch cells on the X-axis is M_x, and the spacing on the Y-axis is M_y;

[0064] like Figure 2 As shown in (b), the length of each rectangular slot in the coupling feed gap pairs 8a, 8b, 8c, and 8d is L. s Width is W s And the distance X from the center of the offset metal rectangular patch 1 slot ;

[0065] Figure 2 (e) is a description of the FSIW cavity structure, and Figure 2 (c) and (d) together describe its internal structural dimensions, where the width is W. siw Length L siw 9a is the metallized through-hole array on the outside of the cavity, 9d is the metallized through-hole array on the inside, 9b is the internal metal plate, and the width of the folded gap is W. f The edge-center metallic perturbation pillar 9c and the radiation matching metallic perturbation pillar 9e are used to bisect higher-order modes and antenna radiation matching, respectively, where Y s X s It is the offset position of the edge center metal micro-perturbation column 9e relative to the metallized through-hole array 9a and the rectangular coupling gap 10 on the outside of the cavity;

[0066] Figure 2 (f) is the coupling slot for energy Y-waveguide transmission to the FSIW cavity, where the length is L. s1 Width is W s1 ;

[0067] M_x In (g), the metal pillar 11c is located in the middle of the entire structure. Its function is to bisect the electric field. The electric field is then refracted by the refractive metal perturbation pillar 11b, and then matched by the coupling matching metal perturbation pillar 11a. The electric field energy is coupled into the FSIW cavity. The relative position of the coupling matching metal perturbation pillar 11a with respect to the short-circuited metal wall is along the Y-axis at a distance of V. y The distance along the X-axis is V x The diameter of the central metallic perturbation pillar 11c is D. v3The diameters of the coupling-matching metal perturbation pillar 11a and the refractive metal perturbation pillar 11b are D, respectively. v1 D v2 The position of the refractive metal perturbation pillar 11b relative to the central metal perturbation pillar 11c is along the X-axis at point D. x D along the Y-axis y The diameter of the metal pillars in the outer metal wall is D. v The spacing is s.

[0068] The specific dimensions for each dimension are shown in the table below (unit: mm):

[0069] [[ L p ]]> [WC p ]]> M_y Figure 3 [[ L s ]]> [WC s ]] X slot ]]> Y s ]]> X s ]] X m ]]> s 3 2.1 6 7 2 0.25 0.8 3.1 1.65 1.65 0.7 L siw ]]> [WC siw ]]> [CD AT W1] L s1 ]]> [WC s1 ]]> Y s1 ]]> X s1 ]]> [WC f ]]> D v ]]> D v3 ]]> D xv3 ]]> 13.2 4.4 3.6 3.2 0.4 1.9 2.2 0.15 0.4 0.5 4

[0070] Figure 4 The figure shows the reflection coefficient and gain curves of the antenna array of this invention. It can be seen that the antenna array has a good reflection coefficient. The |S| of the antenna array can be seen from the figure. 11 With an impedance bandwidth of 27.76-30.26GHz and a relative bandwidth of 8.93%, this antenna array belongs to the narrowband category among millimeter-wave antennas. It also has a relatively high gain, with a maximum peak gain of 12.85dBi.

[0071] Figure 5 The voltage standing wave ratio (VSWR) of the antenna array of this invention is shown to be less than 1.5 within its operating bandwidth.

[0072] Figure 6 The radiation efficiency of the antenna array of the present invention can be seen. It can be seen that the antenna array is above 70% in the operating bandwidth. For a narrowband antenna array, this radiation efficiency is at a relatively normal level. Moreover, the narrowband is more sensitive to frequency. It can be seen that the efficiency is significantly reduced outside the operating bandwidth.

[0073] ​ The figures show the radiation patterns of the 2×2 FSIW millimeter-wave microstrip antenna array based on higher-order modes of this invention at frequencies of (a) 28 GHz, (b) 29 GHz, (c) 30 GHz, and (d) at maximum peak gain of 29.3 GHz. As can be seen from the figures, the antenna array designed in this invention has good directivity, and the highest sidelobe level is below -13.4 dB.

[0074] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-order mode-based FSIW millimeter-wave microstrip antenna, comprising multiple periodically arrayed antenna modules; characterized in that... Each antenna module is a 2×2 antenna array, including an antenna radiating structure, two FSIW cavity structures, and a Y-type waveguide power divider; The antenna radiation structure includes an antenna radiation element, a first dielectric layer (2), and a first metal layer (3). The antenna radiating element comprises four identical metal rectangular patches (1) arranged in a 2×2 array, with gaps between the four metal rectangular patches (1); The first metal layer (3) is etched with four pairs of coupling feed slots (8) corresponding to the metal rectangular patches (1); the center of each metal rectangular patch (1) is aligned with the center of the corresponding coupling feed slot pair (8); The coupling feed gap pair (8) is symmetrical about the axis of the long side of the first dielectric layer (2); The two FSIW cavity structures are symmetrically arranged about the long side of the rectangular coupling slot (10) of the antenna module; each FSIW cavity structure includes a first metal layer (3), a second dielectric layer (4), a second metal layer (5), an intermediate metal layer (9b) disposed in the middle layer of the second dielectric layer (4), a first metallized through-hole array (9a) penetrating the second dielectric layer (4), and a second metallized blind hole array (9d); The second metallized blind hole array (9d) constitutes the FSIW cavity electric wall formed by the overlapping of the two sides of the SIW electric wall after folding; The first metallized through-hole array (9a) consists of two long side metal walls and two short-circuit metal walls on both sides of the FSIW cavity formed by folding and closing the magnetic wall of the SIW. The intermediate metal layer (9b) is formed by the folded surface of SIW. The two short-circuit metal walls surrounded by the first metallized via array (9a) penetrate the intermediate metal layer (9b), wherein the length of the long side of the intermediate metal layer (9b) is longer than the length of the two long side metal walls surrounded by the first metallized via array (9a). The two long side metal walls of the FSIW cavity do not contact the intermediate metal layer (9b); The second metal layer (5) is etched with two rectangular coupling gaps (10), which are located directly below the second metallized blind hole array (9d); The Y-type waveguide power divider is a one-to-two equal power divider; the projections of the two rectangular coupling gaps (10) on the Y-type waveguide power divider are respectively located in the two paths equally divided by the Y-type waveguide power divider.

2. The FSIW millimeter-wave microstrip antenna based on higher-order modes according to claim 1, characterized in that, The spacing M_x between adjacent metal rectangular patches (1) along the short side of the rectangular coupling gap (10) is 0.5λ0~λ0, and the spacing M_y between adjacent metal rectangular patches (1) along the long side of the rectangular coupling gap (10) is 0.5λ0~λ0, where λ0 is the wavelength corresponding to 28GHz in free space.

3. The FSIW millimeter-wave microstrip antenna based on higher-order modes according to claim 1, characterized in that, The width W of the metal rectangular patch (1) p Satisfying 0.28λ0, length L p To satisfy 0.20λ0, the antenna radiation is controlled in the millimeter-wave band.

4. The FSIW millimeter-wave microstrip antenna based on higher-order modes according to claim 1, characterized in that, The distance between the centers of the two FSIW cavities is the same as the spacing between the two metal rectangular patches (1) along the short side of the rectangular coupling gap (10).

5. The FSIW millimeter-wave microstrip antenna based on higher-order modes according to claim 1, characterized in that, It also includes a center-side metal perturbation post (9c) for connecting the intermediate metal layer (9b) and the first metal layer (3), and a radiation matching metal perturbation post (9e) for connecting the intermediate metal layer (9b) and the second metal layer (5), which are used to bisect the higher-order mode and for antenna radiation matching, respectively.

6. The FSIW millimeter-wave microstrip antenna based on higher-order modes according to claim 1, characterized in that, By adjusting the electric wall distance X formed by the edge-center metallic micro-perturbation pillar (9c) and the second metallized blind hole array (9d), m The electric wall distance X formed by the radiation-matched metallic perturbation pillar (9e) and the second metallized blind hole array (9d) s This allows for adjustment of the working bandwidth.

7. The FSIW millimeter-wave microstrip antenna based on higher-order modes according to claim 1, characterized in that, The length L of the rectangular coupling gap (10) s1 For FSIW waveguide wavelength λ g One-quarter of the width of the keystone ensures that the coupling resonance is possible, and its width W is [missing information]. s1 It should be as small as possible.

8. The FSIW millimeter-wave microstrip antenna based on higher-order modes according to claim 1, characterized in that, The Y-type waveguide power divider includes a second metal layer (5), a third dielectric layer (6), a third metal layer (7), a third metallized via array penetrating the third dielectric layer (6), and a coupling matching metal micro-perturbation pillar (11a), a refractive micro-perturbation pillar (11b), and a central metal micro-perturbation pillar (11c). The coupling matching metal perturbation post (11a) and the rectangular coupling slot (10) are used to couple energy from the Y-type waveguide power divider to the two FSIW cavities; the central metal perturbation post (11c) that divides the input signal energy is placed at the bifurcation position of the "Y", and the distance D between the central metal perturbation post (11c) and the input port is adjusted. xv3 The energy that will be divided will be coupled to the refractive perturbation column (11b), and then coupled to the rectangular coupling gap (10) at a 90-degree angle.

9. The FSIW millimeter-wave microstrip antenna based on higher-order modes according to claim 8, characterized in that, The coupling matching metal micro-perturbation pillar (11a), the refractive micro-perturbation pillar (11b), the central metal micro-perturbation pillar (11c), the first metallized through-hole array (9a), and the second metallized blind hole array (9d) have the same aperture.

10. The FSIW millimeter-wave microstrip antenna based on higher-order modes according to claim 8, characterized in that: The input electric field at the input terminal is TE 10 The signal of the mode is split into two equally divided half-power signals by the Y-type waveguide power divider; the half-power signals at both ends are coupled to the two FSIW cavities through the rectangular coupling gap (10); The FSIW cavity width is selected according to the designed frequency band, as shown in the following formula: ； Among them, C o d represents the speed of light, s represents the diameter of the through-hole, and s represents the spacing between the through-holes. TE 20 The cutoff frequency of the mode; Because the width of the second metallized blind hole array (9d) is not equal to the width of the upper and lower layers of the FSIW after folding the SIW, a correction term is introduced. : ； For reference, select the fold gap width W. f ; Based on waveguide wavelength One-quarter of the length L of the rectangular coupling gap (10) s1 ; ； in, This indicates the wavelength in free space of the center frequency of the selected millimeter-wave band. Indicates the cutoff frequency of the FSIW; The electric field TE of the signal 10 The model, through the coupling effect of the rectangular coupling gap (10), generates TE signals with opposite phases on both sides of the long side of the rectangular coupling gap (10). 20 The higher-order mode electric field was then introduced, and then a metal micro-perturbation pillar (9c) was introduced at the center of the edge to expand the frequency bandwidth. Electromagnetic simulation was performed by moving the pillar along the short side of the rectangular coupling gap (10) at the center of the upper and lower layers of the FSIW to obtain the optimal performance position. The optimal position is located on the upper layer of the FSIW and at a distance from the second metallized blind hole array (9d) along the short side of the rectangular coupling gap (10). s ; Finally, TE 20 Under the matching effect of the radiation-matching metal perturbation pillar (9e) in the lower layer of the FSIW cavity, the electric field forms a radiation source at the coupled feed gap pair (8); TE 20 The two electric fields of the mode are out of phase and act on the rectangular coupling gap (10) in the two folded FSIW cavities, generating the same radiation field source and coupling to the metal rectangular patch (1), generating current in the same direction. The currents are superimposed, and the metal rectangular patch (1) radiates energy outward.

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