Broadband low-profile low-cross-polarization dielectric patch antenna

Abstract

The invention discloses a broadband low-profile low-cross-polarization dielectric patch antenna which comprises a dielectric body, and metal patches, slot metal sheets, a coupling microstrip line and a metal floor which are arranged on the dielectric body, are supported by the dielectric body, are parallel to one another, are separated from one another and are sequentially stacked in an up-and-down layered manner. Wherein a gap is formed in the gap metal sheet; the coupling microstrip line is located below the gap. The metal patch is a square sheet body. And four corners of the square sheet body metal patch are connected with four metal columns. The metal column is arranged in the medium body and located between the metal patch and the gap metal sheet, and the top end of the metal column is connected with the metal patch. The coupling microstrip line is connected with the feed microstrip line. The gap comprises a U-shaped gap and an H-shaped gap surrounded by the U-shaped gap. The coupling microstrip line is T-shaped. Compared with a common patch antenna, the antenna provided by the invention is small in size and profile, and has a wider bandwidth and a good radiation characteristic.

Description

Technical Field

[0001] The present invention relates to a dielectric patch antenna, and particularly to a dielectric patch antenna with low cross - polarization gap coupling. Background Art

[0002] An antenna is an essential component in electronic engineering and wireless communication for transmitting and receiving electromagnetic waves. With the rapid development of wireless communication technology, higher performance requirements are imposed on antennas. Wideband, low - profile, and low cross - polarization are important directions in current antenna design. In the microwave band, especially in the frequency range of 11 GHz to 13 GHz, the design of antennas needs to meet specific performance requirements such as impedance bandwidth, cross - polarization, and beam width.

[0003] A dielectric patch antenna is a patch antenna with a dielectric as the resonator and waveguide core. This antenna enhances the coupling efficiency and improves the energy transmission efficiency through the electromagnetic coupling formed by the dielectric and the feeding structure; at the same time, it restricts the propagation of electromagnetic waves within a specific path through the low - loss and high - dielectric - constant characteristics of the dielectric, optimizing the radiation direction. In addition, the shape of the antenna dielectric and the feeding position can regulate the TE, TM and other resonance modes of the antenna electromagnetic waves, achieving high radiation efficiency. Summary of the Invention

[0004] The problems to be solved by the present invention: Achieve performance requirements such as impedance bandwidth, cross - polarization, and beam bandwidth of the antenna in the frequency range of 11 GHz to 13 GHz.

[0005] To solve the above problems, the following solutions are adopted in the present invention: A broadband low - profile low - cross - polarization dielectric patch antenna according to the present invention includes a dielectric body, and a metal patch, a slot metal sheet, a coupling microstrip line, and a metal floor which are arranged on the dielectric body, supported by the dielectric body, parallel to each other, separated from each other, and stacked in sequence in the up - down direction; wherein, a slot is provided on the slot metal sheet; the coupling microstrip line is located below the slot; the metal patch is a square sheet; four metal columns are vertically connected to the four corners of the square - sheet metal patch; the metal columns are arranged in the dielectric body, between the metal patch and the slot metal sheet, and the top ends are connected to the metal patch; the coupling microstrip line is connected to a feeding microstrip line.

[0006] Further, the metal columns are connected to the metal patch by welding.

[0007] Further, the slot metal sheet is a square sheet; the size of the slot metal sheet is larger than that of the metal patch, and the center of the slot metal sheet is aligned with the center of the metal patch.

[0008] Furthermore, the dielectric body includes a first dielectric layer, a second dielectric layer, and a third dielectric layer; the metal patch is disposed on the top surface of the first dielectric layer; the slot metal sheet is disposed on the top surface of the second dielectric layer; the feeding microstrip line and the coupling microstrip line are disposed on the top surface of the third dielectric layer; the bottom surface of the third dielectric layer is connected to the metal floor; the bottom surface of the second dielectric layer covers the coupling microstrip line and the feeding microstrip line disposed on the third dielectric layer and is joined to the third dielectric layer; the bottom surface of the first dielectric layer covers the slot metal sheet disposed on the second dielectric layer and is joined to the second dielectric layer.

[0009] Furthermore, the dielectric constant of the first dielectric layer is 1.06 and the tangent of the loss angle is 0.0001; the dielectric constant of the second dielectric layer is 2.20 and the tangent of the loss angle is 0.0009; the dielectric constant of the third dielectric layer is 2.20 and the tangent of the loss angle is 0.0009.

[0010] Furthermore, the thicknesses of the second dielectric layer and the third dielectric layer are 0.02A, where A is the center wavelength of the operating frequency of the antenna.

[0011] Furthermore, the slot includes a U-shaped slot; the U-shaped slot includes a bottom slot and two first side slots that are parallel to each other, equal in length, and flush at both ends; the bottom slot is perpendicularly connected to one end of the two first side slots, so that the bottom slot and the two first side slots are connected and form a U-shaped structure.

[0012] Furthermore, the slot further includes an H-shaped slot; the H-shaped slot is located inside the U-shaped slot and includes a middle slot and two second side slots that are parallel to each other, equal in length, and flush at both ends; the two second side slots are located between the two first side slots and are parallel to the first side slots, and the distances from each of the two second side slots to the adjacent first side slot are equal; the middle slot is perpendicularly connected to the two second side slots, so that the middle slot and the two second side slots form an H-shaped structure.

[0013] Furthermore, the coupling microstrip line includes a first microstrip line and a second microstrip line; wherein, the length direction of the first microstrip line is parallel to the first side slot and is on the central axis between the two first side slots; the length direction of the second microstrip line is perpendicular to the first side slot and is on the central axis between the two first side slots, and the front projection of the second microstrip line on the slot metal sheet is located inside the U-shaped slot; one end of the first microstrip line is connected to the feeding microstrip line, and the other end is connected to the second microstrip line, and forms a T-shaped structure with the second microstrip line.

[0014] Furthermore, the front projection of the second microstrip line on the slot metal sheet does not exceed the rectangular area enclosed by the bottom slot, the middle slot, and the two first side slots.

[0015] The technical effects of the present invention are as follows: 1. The four metal posts connected to the four corners at the bottom of the metal patch of the present invention can effectively expand the impedance bandwidth of the low frequency and also play a role in fixing the metal patch; 2. The operating frequency range of the antenna of the present invention is 11G - 13GHz. It covers multiple frequency bands and meets the requirements of modern wireless communication for broadband. Compared with traditional patch antennas, the bandwidth of the present invention is wider, enabling it to adapt to more application scenarios; 3. The size and profile of the antenna of the present invention are small, which is conducive to the integration of devices and meets the requirements of the development of small and portable devices; 4. The antenna of the present invention guides the current flow path through the double - slot structure of the U - shaped slot and the H - shaped slot, introducing more resonance modes. The cross - polarizations of these resonance modes cancel each other out, thereby reducing the overall cross - polarization level, making the cross - polarization lower than - 30dB and improving the communication efficiency of the device; 5. By adding a smaller U - shaped slot inside the U - shaped slot, a relative bandwidth of about 16% can be achieved under the index requirement that the impedance bandwidth is less than - 10dB. However, under the index requirement that the impedance bandwidth is less than - 15dB, the relative bandwidth deteriorates. The present invention optimizes the anti - phase TM 20 resonance mode by adding an H - shaped slot inside the U - shaped slot, so as to achieve a wider bandwidth under higher impedance bandwidth index requirements. Description of the Drawings

[0016] Figure 1 is the overall three - dimensional structure schematic diagram of the dielectric patch antenna embodiment of the present invention.

[0017] Figure 2 is the structure schematic diagram and dimension marking diagram of the cross - sectional view of the dielectric patch antenna embodiment of the present invention.

[0018] Figure 3 is the structure schematic diagram and dimension marking diagram of the top - view projection of the dielectric patch antenna embodiment of the present invention.

[0019] Figure 4 is the reflection coefficient curve graph of the dielectric patch antenna embodiment of the present invention.

[0020] Figure 5 is the cross - polarization curve graph of the dielectric patch antenna embodiment of the present invention.

[0021] Figure 6 is the antenna gain curve graph of the dielectric patch antenna embodiment of the present invention.

[0022] Figure 7 and Figure 8 are respectively the antenna gain curve graphs of the E - plane and H - plane of the dielectric patch antenna embodiment of the present invention.

[0023] Figure 1 、 Figure 2 、 Figure 3 In 1 is a metal patch, 2 is a slotted metal sheet, 3 is a coupled microstrip line, 31 is the first microstrip line, 32 is the second microstrip line, 4 is a metal ground plane, 5 is a slot, 51 is a U-shaped slot, 511 is the bottom slot, 512 is the first side slot, 52 is an H-shaped slot, 521 is the middle slot, 522 is the second side slot, 6 is a metal post, 9 is a dielectric body, 91 is the first dielectric layer, 92 is the second dielectric layer, 93 is the third dielectric layer. For the convenience of illustration, Figure 1 in which, the first dielectric layer 91 and the second dielectric layer 92 are made transparent and are represented by dashed lines. Detailed implementation manner

[0024] The present invention will be further described in detail below with reference to the accompanying drawings.

[0025] Figure 1 An example of a broadband low-profile and low cross-polarization dielectric patch antenna is provided, which includes a dielectric body 9 and a metal patch 1, a slotted metal sheet 2, a coupled microstrip line 3, and a metal ground plane 4 that are arranged on the dielectric body 9 and supported by the dielectric body 9, are parallel to each other, are separated from each other, and are stacked in sequence layer by layer from top to bottom. Among them, a slot 5 is provided on the slotted metal sheet 2. The coupled microstrip line 3 is opposite to the slot 5, is connected to a feeding microstrip line 39, and is connected to a radio frequency connector through the feeding microstrip line 39.

[0026] The metal ground plane 4 is a sheet-like body for grounding. For the convenience of description, in this specification, the metal ground plane 4 is used as the reference ground, and the plane of the metal ground plane 4 is used as the horizontal plane. The side far from the metal ground plane 4 is the upper side, and the side close to the metal ground plane 4 is the lower side. Based on the above reference, the dielectric patch antenna of the present invention is divided into four layers from top to bottom: the first layer, the metal patch layer, which is provided with the metal patch 1; the second layer, the coupled slot layer, which is provided with the slotted metal sheet 2; the third layer, the coupled microstrip layer, which is provided with the coupled microstrip line 3; the fourth layer, the metal ground plane layer, which is provided with the metal ground plane 4. The metal patch 1, the slotted metal sheet 2, and the coupled microstrip line 3 are all metal thin sheets. Referring to Figure 2 and Figure 3 , their thicknesses are respectively marked as H1, H2, and H3.

[0027] For the assembly of the above four-layer structure, the dielectric body is naturally divided into three layers: the first dielectric layer 91 provided with the metal patch 1, the second dielectric layer 92 provided with the slot metal sheet 2, and the third dielectric layer 93 provided with the coupled microstrip line 3 and the metal floor 4. Specifically, the metal patch 1 is disposed on the top surface of the first dielectric layer 91. The slot metal sheet 2 is disposed on the top surface of the second dielectric layer 92. The feeding microstrip line 39 and the coupled microstrip line 3 are disposed on the top surface of the third dielectric layer 93. The metal floor 4 is disposed below the third dielectric layer 93, that is, the bottom surface of the third dielectric layer 93 is connected to the metal floor 4. The bottom surface of the second dielectric layer 92 covers the coupled microstrip line 3 and the feeding microstrip line 39 disposed on the third dielectric layer 93 and is joined to the third dielectric layer 93. The bottom surface of the first dielectric layer 91 covers the slot metal sheet 2 disposed on the second dielectric layer 92 and is joined to the second dielectric layer 92. The aforementioned top surface and bottom surface are the upper and lower two surfaces of the dielectric layer.

[0028] In this embodiment, the first dielectric layer 91 is made of an insulating dielectric material with a dielectric constant of 1.06 and a loss tangent of 0.0001, and the thickness is H91. The second dielectric layer 92 and the third dielectric layer 93 are made of an insulating dielectric material with a dielectric constant of 2.20 and a loss tangent of 0.0009, and the thicknesses are H92 and H93 respectively. Specifically, in this embodiment, Cuming Microwave C-Foam PF-4 is used as the material of the first dielectric layer 91, and Rogers RT5880 is used as the material of the second dielectric layer 92 and the third dielectric layer 93. The Cuming Microwave C-Foam PF-4 plate has a dielectric constant of 1.06 and a loss tangent of 0.0001; the Rogers RT5880 plate has a dielectric constant of 2.20 and a loss tangent of 0.0009.

[0029] The metal patch 1 is a square sheet with a side length of L1 and a thickness of H1. Four metal posts 6 are perpendicularly connected to the four corners of the square sheet metal patch 1. The metal posts 6 are used to expand the impedance bandwidth of the low frequency, are disposed in the dielectric body 9, are located between the metal patch 1 and the slot metal sheet 2, and the top ends are connected to the metal patch 1. The metal posts 6 are cylinders with a height of H6 and a diameter of D6. The metal posts 6 are perpendicularly connected to the metal patch 1, and the distance between the connection part and the edge of the metal patch 1 is D16. In this embodiment, the metal posts 6 and the metal patch 1 are preferably connected by welding. After the metal posts 6 and the metal patch 1 are welded, they are integrally formed with the first dielectric layer 91, so that the metal posts 6 are buried in the first dielectric layer 91, and the metal patch 1 is attached to the surface of the first dielectric layer 91. Since the metal posts 6 are integrally formed with the first dielectric layer 91 within the first dielectric layer 91, and the metal posts 6 are welded to the metal patch 1, the metal posts 6 also play a role in fixing the metal patch 1.

[0030] In this embodiment, the slotted metal sheet 2 is a square sheet with side length L2 and thickness H2. The size of the slotted metal sheet 2 is larger than that of the metal patch 1, and the center of the slotted metal sheet 2 is aligned with the center of the metal patch 1. Specifically, L2 > L1. The alignment of the centers of the slotted metal sheet 2 and the metal patch 1 means that the distance between the edge of the front projection of the metal patch 1 on the slotted metal sheet 2 and the edge of the slotted metal sheet 2 is (L2 - L1) / 2. The slot 5 on the slotted metal sheet 2 includes a U-shaped slot 51 and an H-shaped slot 52.

[0031] The U-shaped slot 51 includes a bottom slot 511 and two first side slots 512 that are parallel, equal in length, and flush at both ends. The bottom slot 511 perpendicularly connects one end of the two first side slots 512, so that the bottom slot 511 and the two first side slots 512 are connected and form a U-shaped structure. The bottom slot 511 and the first side slots 512 are both parallel to the edge of the slotted metal sheet 2. The length of the first side slot 512 is L512, and the spacing between the two first side slots is W512. The spacing W512 between the two first side slots is also the length of the bottom slot 511. The slot widths of the bottom slot 511 and the first side slots 512 are the same, both being W5. The distance between the bottom slot 511 and the edge of the slotted metal sheet 2 is D51, and the distance between the first side slot 512 and the edge of the slotted metal sheet 2 is D52. The U-shaped slot 51 is located at the center of the slotted metal sheet 2. Specifically, D52 satisfies the condition: D52 = (L2 - 2×W5 - W512) / 2.

[0032] The H-shaped slot 52 is located inside the U-shaped slot 51 and includes a middle slot 521 and two second side slots 522 that are parallel, equal in length, and flush at both ends. The two second side slots 522 are located between the two first side slots 512 and are parallel to the first side slots 512. The middle slot 521 perpendicularly connects the two second side slots 522, so that the middle slot 521 and the two second side slots 522 form an H-shaped structure. The distances from the two second side slots 522 to the adjacent first side slots 512 are respectively equal. The length of the second side slot 522 is L522, and the spacing between the two second side slots is W522. The spacing W522 between the two second side slots is also the length of the middle slot 521. The slot widths of the middle slot 521 and the second side slots 522 are the same, both being W5. The distance between the inner end of the second side slot 522 and the bottom slot 511 is D53, the distance from the middle slot 521 to the inner end of the second side slot 522 is D54, and the distance between the second side slot 522 and the adjacent first side slot 512 is D55. The fact that the distances from the two second side slots 522 to the adjacent first side slots 512 are respectively equal means that the distance D55 between the second side slot 522 and the adjacent first side slot 512 satisfies the condition: D55 = (W512 - 2×W5 - W522) / 2. Here, the inner end of the second side slot 522 refers to the end of the second side slot 522 facing the bottom slot 511.

[0033] The coupled microstrip line 3 is located below the slot 5 and is directly opposite to the slot 5. In this embodiment, the coupled microstrip line 3 includes a first microstrip line 31 and a second microstrip line 32. Among them, the length direction of the first microstrip line 31 is parallel to the first side slot 512 and is located on the central axis between the two first side slots 512. The length direction of the second microstrip line 32 is perpendicular to the first side slot 512 and is located on the central axis between the two first side slots 512, and its front projection on the slot metal sheet 2 is located inside the U-shaped slot 51. Specifically, the front projection of the second microstrip line 32 on the slot metal sheet 2 does not exceed the rectangular area enclosed by the bottom slot 511, the middle slot 521, and the two first side slots 512. One end of the first microstrip line 31 is connected to the feeding microstrip line 39, and the other end is connected to the second microstrip line 32, and they form a T-shaped structure with the second microstrip line 32. More specifically, in this embodiment, the first microstrip line 31 and the feeding microstrip line 39 are an integrated microstrip line. The first microstrip line 31 is the part that overlaps with the slot metal sheet 2 when the integrated microstrip line is projected onto the slot metal sheet 2, and the part outside the slot metal sheet 2 is the feeding microstrip line 39. The length of the first microstrip line 31 is L31, which is also the distance between the edge of the second microstrip line 32 and the edge of the slot metal sheet 2. The width of the first microstrip line W31 is also the width of the feeding microstrip line 39. The length of the second microstrip line 32 is L32, and the width is W32.

[0034] In this embodiment, the configuration of each dimensional parameter is as follows: The thickness of the metal patch 1 is H1 = 0.10 mm, and the side length is L1 = 6.16 mm; The thickness of the slot metal sheet 2 is H2 = 0.10 mm, and the side length is L2 = 7.50 mm; The slot widths of the bottom slot 511, the first side slots 512, the middle slot 521, and the second side slots 522 are W5 = 0.15 mm; The length of the first side slot 512 is L512 = 4.78 mm, and the distance between the two first side slots 512 is W512 = 2.85 mm; The distance between the bottom slot 511 and the edge of the slot metal sheet 2 is D51 = 0.65 mm; The distance between the first side slot 512 and the edge of the slot metal sheet 2 is D52 = 2.175 mm; The length of the second side slot 522 is L522 = 2.80 mm, and the distance between the two second side slots 522 is W522 = 0.65 mm; The distance between the inner end of the second side slot 522 and the bottom slot 511 is D53 = 1.79 mm; The distance from the middle slot 521 to the inner end of the second side slot 522 is D54 = 0.485 mm; The distance between the second side slot 522 and the first side slot 512 is D55 = 0.95 mm; The thickness of the coupled microstrip line 3 is H3 = 0.10 mm; The length of the first microstrip line 31 is L31 = 1.73 mm, and the width is W31 = 1.20 mm; The length of the first microstrip line 31 is L32 = 2.14 mm, and the width is W32 = 1.48 mm; The thickness of the metal floor 4 is H4 = 0.10 mm; The thickness of the first dielectric layer 91 is H91 = 3.28 mm; The thickness of the second dielectric layer 92 is H92 = 0.51 mm; The thickness of the third dielectric layer 93 is H93 = 0.51 mm.

[0035] The operating frequency of the antenna in this embodiment under the above size parameter configuration is 11G - 13GHz, corresponding to a wavelength range of 23.06 - 27.25 mm, the center frequency is 12GHz, and the center wavelength is A = 25 mm.

[0036] According to the influence of the substrate thickness on the surface wave, when the substrate thickness satisfies the influence of the surface wave can be ignored, where T is the substrate thickness, A is the wavelength of the electromagnetic wave, is the dielectric constant of the substrate. In this embodiment, the dielectric constants of the second dielectric layer 92 and the third dielectric layer 93 as the substrate are 2.2, and it can be obtained that when the substrate thickness satisfies the influence of the surface wave can be ignored. In this embodiment, to minimize the influence of the surface wave as much as possible, the thickness of 0.51 mm of the second dielectric layer 92 and the third dielectric layer 93 is equivalent to 0.02A.

[0037] Figure 4 Shows the reflection coefficient of the dielectric patch antenna in this embodiment when operating at 11G - 13GHz. It can be seen from this figure that the reflection coefficient of the dielectric patch antenna in this embodiment when operating at 11G - 13GHz is less than -20 dB, especially close to -30 dB at 11.2 GHz.

[0038] Figure 5 Shows the cross - polarization of the dielectric patch antenna in this embodiment when operating at 11G - 13GHz. It can be seen from this figure that the cross - polarization of the dielectric patch antenna in this embodiment when operating at 11G - 13GHz is -33 dB - -38 dB, lower than the design requirement of -30 dB.

[0039] Figure 6 Shows the gain of the dielectric patch antenna in this embodiment when operating at 11G - 13GHz. It can be seen from this figure that the gain of the dielectric patch antenna in this embodiment when operating at 11G - 13GHz is above 6.5 dB.

[0040] Figure 7 and Figure 8Shows the gain of the dielectric patch antenna of this embodiment in space. It can be seen from this figure that the dielectric patch antenna of this embodiment has good antenna gain in the range of -20 degrees to 20 degrees in the front direction.

Claims

1. A broadband low-profile low cross-polarization dielectric patch antenna, characterized in that: The invention comprises a dielectric body (9), and metal patches (1), slot metal sheets (2), coupling microstrip lines (3), and metal floor (4) which are arranged on the dielectric body (9) and supported by the dielectric body (9), are parallel to each other, are separated from each other, and are stacked in order in layers up and down; wherein a slot metal sheet (2) is provided with a slot (5); the coupling microstrip line (3) is located below the slot (5); the metal patch (1) is a square sheet; four metal columns (6) are vertically connected to the four corners of the square sheet metal patch (1); the metal column (6) is arranged in the dielectric body (9), is located between the metal patch (1) and the slot metal sheet (2), and is connected to the metal patch (1) at its top; and the coupling microstrip line (3) is connected to the feeding microstrip line (39).

2. The broadband low-profile low cross-polarization dielectric patch antenna according to claim 1, characterized in that: The metal column (6) is connected to the metal patch (1) by welding.

3. The broadband low-profile low cross-polarization dielectric patch antenna according to claim 1, characterized in that: The slot metal sheet (2) is a square sheet; the size of the slot metal sheet (2) is larger than the metal patch (1), and the center of the slot metal sheet (2) is aligned with the center of the metal patch (1).

4. The broadband low-profile low cross-polarization dielectric patch antenna according to claim 1, characterized in that: The dielectric body (9) comprises a first dielectric layer (91), a second dielectric layer (92) and a third dielectric layer (93); the metal patch (1) is arranged on the top surface of the first dielectric layer (91); and the gap metal sheet (2) is arranged on the top surface of the second dielectric layer (92); The feeding microstrip line (39) and the coupling microstrip line (3) are arranged on the top surface of the third dielectric layer (93); the bottom surface of the third dielectric layer (93) is connected to the metal floor (4); the bottom surface of the second dielectric layer (92) covers the coupling microstrip line (3) and the feeding microstrip line (39) arranged on the third dielectric layer (93) and is joined to the third dielectric layer (93); the bottom surface of the first dielectric layer (91) covers the slotted metal sheet (2) arranged on the second dielectric layer (92) and is joined to the second dielectric layer (92).

5. The broadband low-profile low cross-polarization dielectric patch antenna according to claim 4, characterized in that: The dielectric constant of the first dielectric layer (91) is 1.06, and the loss tangent is 0.0001; the dielectric constant of the second dielectric layer (92) is 2.20, and the loss tangent is 0.0009; and the dielectric constant of the third dielectric layer (93) is 2.20, and the loss tangent is 0.0009.

6. The broadband low-profile low cross-polarization dielectric patch antenna according to claim 5, characterized in that: The thickness of the second dielectric layer (92) and the third dielectric layer (93) is 0.02A, where A is the central wavelength of the antenna operating frequency.

7. The broadband low-profile low cross-polarization dielectric patch antenna according to claim 1 or 2 or 3 or 4 or 5 or 6, characterized in that: The gap (5) comprises a U-shaped gap (51); the U-shaped gap (51) comprises a bottom gap (511) and two first side gaps (512) which are parallel to each other and of equal length and flush at both ends; the bottom gap (511) vertically connects one end of the two first side gaps (512), so that the bottom gap (511) and the two first side gaps (512) are connected to form a U-shaped structure.

8. The broadband low-profile low cross-polarization dielectric patch antenna according to claim 7, characterized in that: The gap (5) further comprises an H-shaped gap (52); the H-shaped gap (52) is located inside the U-shaped gap (51), and comprises a center gap (521) and two second side gaps (522) which are parallel to each other and of equal length and flush at both ends; the two second side gaps (522) are located between the two first side gaps (512) and are parallel to the first side gaps (512), and are each equidistant from the adjacent first side gaps (512); the center gap (521) vertically connects the two second side gaps (522), so that the center gap (521) and the two second side gaps (522) form an H-shaped structure.

9. The broadband low-profile low cross-polarization dielectric patch antenna according to claim 8, characterized in that: The coupled microstrip line (3) comprises a first microstrip line (31) and a second microstrip line (32); wherein the length direction of the first microstrip line (31) is parallel to the first side seams (512) and is located on the center axis between the two first side seams (512); the length direction of the second microstrip line (32) is perpendicular to the first side seams (512) and is located on the center axis between the two first side seams (512), and its front projection on the gap metal sheet (2) is located inside the U-shaped gap (51); one end of the first microstrip line (31) is connected to the feeding microstrip line (39), and the other end is connected to the second microstrip line (32), and forms a T-shaped structure with the second microstrip line (32).

10. The broadband low-profile low cross-polarization dielectric patch antenna according to claim 9, characterized in that: The front projection of the second microstrip line (32) on the slotted metal sheet (2) does not exceed the rectangular area surrounded by the bottom slot (511), the middle slot (521) and the two first side slots (512).

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