A SIW-based microstrip patch antenna with circular polarization and filtering response

Abstract

The present invention relates to a SIW-based microstrip patch antenna with circular polarization and filtering response, belonging to the field of wireless energy transmission. The antenna comprises an SIW cavity structure arranged on a lower layer and a microstrip patch structure arranged on an upper layer. The SIW cavity structure comprises a lower dielectric substrate, a bottom metal floor, a middle metal floor and four groups of metallized through holes. The four groups of metallized through holes penetrate the lower dielectric substrate, the bottom metal floor and the middle metal floor to form a square SIW cavity. A pair of metallized through holes is arranged at the upper left and lower right corners of the SIW cavity relative to the midline where a feeding point is located, serving as disturbance columns. Two pairs of metallized through holes are arranged in pairs at the center of the SIW cavity, serving as matching columns. A feeding hole is also provided in the SIW cavity. A rectangular slot is respectively provided on four sides of the SIW cavity. The microstrip patch structure comprises an upper dielectric substrate and four orthogonally arranged square microstrip patches.

Description

Technical Field

[0001] The invention belongs to the field of wireless energy transmission and relates to a SIW-based microstrip patch antenna with circular polarization and filtering response. Background Art

[0002] With the rapid development of communication systems, the requirements for antennas are no longer simple signal transceivers. Antennas are often required to have high performance while also having multiple functions. This has brought unprecedented challenges to the antenna field.

[0003] Traditional antennas require cascaded filters for frequency selection, which often results in excessively large RF front-end components and hinders system integration. Antenna polarization is also a key indicator of antenna performance. Linear polarization often suffers from signal distortion caused by channel polarization and multipath effects. Therefore, satellite antennas often use circular polarization. Circular polarization can receive signals of all polarizations, and its radiated signals can also be received by antennas with different polarizations. However, existing circularly polarized antennas often have narrow axial bandwidths and poor circular polarization performance. To account for polarization, many circularly polarized antennas have complex structures, making them difficult to manufacture. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a circularly polarized filtering microstrip patch antenna based on SIW to solve the problem of miniaturization of RF front-end circuits. At the same time, the antenna has good circular polarization performance and other properties. Through design and optimization, the structure of the antenna is simplified and easy to process and manufacture.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A SIW-based microstrip patch antenna with circular polarization and filtering response, comprising a SIW cavity structure arranged at a lower layer and a microstrip patch structure arranged at an upper layer;

[0007] The SIW cavity structure includes a lower dielectric substrate, a bottom metal floor, a middle metal floor, and four groups of metallized through holes. The bottom metal floor is arranged on the lower surface of the lower dielectric substrate, and the middle metal floor is arranged on the upper surface of the lower dielectric substrate. The four groups of metallized through holes penetrate the lower dielectric substrate, the bottom metal floor, and the middle metal floor, serving as cavity columns, and enclosing a square SIW cavity. A pair of metallized through holes is arranged at the upper left and lower right corners of the SIW cavity relative to the midline of the feeding point, serving as disturbance columns. Two pairs of metallized through holes are arranged in pairs at the center of the SIW cavity, serving as matching columns. A feeding hole is also provided in the SIW cavity, and the feeding hole is in a straight line with one of the pairs of matching columns. A rectangular slot is provided on each of the four sides of the SIW cavity.

[0008] The microstrip patch structure includes an upper dielectric substrate and four square microstrip patches, wherein the four square microstrip patches are orthogonally arranged on the upper surface of the upper dielectric substrate; the lower surface of the upper dielectric substrate is bonded to the middle metal floor.

[0009] Furthermore, the four square microstrip patches are arranged around the upper dielectric substrate, and the centers of the patches and the centers of the slots in the SIW structure are at the same position.

[0010] Furthermore, the SIW cavity structure of the lower layer is fitted with the microstrip patch structure of the upper layer in a vertical manner and fixed by using fixing holes at four corners, and the fixing holes penetrate all layers.

[0011] Furthermore, four groups of cavity columns are evenly distributed around the lower dielectric substrate. The side length of the enclosed cavity is 44.1 mm, the diameter of the cavity column is 0.8 mm, and the distance between the cavity columns is 1.2 mm.

[0012] Furthermore, the diameter of the disturbance column is 1.1 mm, and the shortest distance from the center of the four groups of cavity columns is 6.7 mm.

[0013] Furthermore, the diameter of the matching column is 1.6 mm, the spacing between a pair of matching columns on the center line of the feed point is 3.8 mm, and the spacing between a pair of matching columns on the center line perpendicular to the center line is 6.6 mm.

[0014] Furthermore, the rectangular groove is 6 mm long, 1.2 mm wide, and 7.1 mm away from the four groups of cavity column edges.

[0015] Furthermore, the side length of the patch is 16.7 mm, and the distance between the side of the patch close to the edge of the upper dielectric substrate and the edge of the upper dielectric substrate is 6.35 mm.

[0016] Furthermore, the thickness of the lower dielectric substrate and the upper dielectric substrate are both 1 mm, the side length is 63 mm, the relative dielectric constant is 2.55, and the loss tangent is 0.0015; the diameter of the fixing hole is 6.6 mm, and the distance between the center of the fixing hole and the edges of the two dielectric substrates is 6.5 mm; the shortest distance between the feeding position and the edge of the metallized through hole is 10.5 mm.

[0017] The beneficial effects of the present invention are:

[0018] (1) SIW technology is used to achieve a basic resonant mode. The feed position is then adjusted and a disturbance column is introduced to achieve a dual-mode resonant mode, which is then rotated to form circular polarization, forming an axial ratio minimum point. Four rectangular slots are then etched around the upper surface of the SIW cavity, and a layer of microstrip patch structure is added. The patch position corresponds to the rectangular slot, which excites the dual mode on the microstrip patch, expands the impedance bandwidth, and introduces another axial ratio minimum point. This method not only enhances the impedance bandwidth and axial ratio bandwidth, but also maintains a flat and high achievable gain. Because the patch current excited by the parasitic mode is reversed, a radiation zero point is introduced, which enhances the filtering performance of the antenna.

[0019] (2) The antenna operates at a center frequency of 5.125 GHz, an impedance bandwidth of 6.9% (4.95-5.3 GHz), an axial ratio bandwidth of 4.2% (5-5.21 GHz), and can achieve a gain of up to 8.4 dBi.

[0020] (3) While achieving high performance, the antenna's filtering response is also guaranteed, with attenuation on both sides of the passband greater than 20dB, and the antenna's profile height is only 0.033λ0. This antenna has excellent performance, a small size, multiple functions, and a simple structure, and has certain engineering value.

[0021] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0023] Figure 1 Schematic diagram of the structure of the circularly polarized filtering microstrip patch antenna based on SIW according to the present invention;

[0024] Figure 2 Schematic diagram of the dimensions of the SIW-based circularly polarized filtering microstrip patch antenna of the present invention;

[0025] Figure 3 The circularly polarized filtering microstrip patch antenna S based on SIW of the present invention 11 Parameters, achievable gain and AR bandwidth plots;

[0026] Figure 4The radiation patterns of the circularly polarized filtering microstrip patch antenna based on SIW according to the present invention are as follows: (a) is the normalized radiation pattern of the antenna in the E plane at 5.03 GHz, (b) is the normalized radiation pattern of the antenna in the H plane at 5.03 GHz; (c) is the normalized radiation pattern of the antenna in the E plane at 5.17 GHz, and (d) is the normalized radiation pattern of the antenna in the H plane at 5.17 GHz.

[0027] Reference numerals: bottom metal floor 1 , middle metal floor 2 , lower dielectric substrate 3 , upper dielectric substrate 4 , feeding hole 5 , matching column 6 , disturbance column 7 , cavity column 8 , rectangular slot 9 , microstrip patch 10 , fixing hole 11 . DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0029] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0030] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0031] See attached Figure 1The present invention provides a circularly polarized filtering microstrip patch antenna based on SIW, which includes a bottom metal floor 1, a middle metal floor 2, a lower dielectric substrate 3, an upper dielectric substrate 4, a feeding hole 5, a matching column 6, a disturbance column 7, a cavity column 8, a rectangular slot 9, a microstrip patch 10, and a fixing hole 11. The middle metal floor 2 is provided on the upper surface of the lower dielectric substrate 3, and the bottom metal floor 1 is provided on the lower surface. A square SIW cavity is placed in the metal floor 2, with a total of four groups of cavity columns 8, 37 in each group. Feeding holes 5, matching columns 6 and disturbance columns 7 are provided in the SIW cavity, which, like the cavity columns, respectively penetrate the bottom metal floor 1, the middle metal floor 2 and the lower dielectric substrate 3. On the middle metal floor 2, a rectangular slot 9 is provided on each side of the SIW cavity. Four orthogonally placed microstrip patches 10 are provided on the upper surface of the upper dielectric substrate 4.

[0032] The two metal floors are the same size as the two dielectric substrates, both measuring 63mm. The minimum distance between the feed point and the edge of the SIW cavity is 10.5mm. The diameter of the matching post is 1.6mm. The distance between a pair of matching posts on the same line as the feed hole is 3.8mm, and the distance between a pair of matching posts perpendicular to the line is 6.6mm. The diameter of the disturbance post is 1.1mm, and the minimum distance from the edge of the SIW cavity is 6.7mm. The rectangular slot is 6mm long and 1.2mm wide, with the minimum distance from its center to the edge of the SIW cavity being 7.1mm. The distance between the cavity posts is 1.2mm, and the diameter is 0.8mm. The patch has a side length of 16.7mm, and the distance from the edge of the dielectric substrate to the edge of the dielectric substrate is 6.35mm. The copper thickness of the metal floor and patch is 0.017mm, and the thickness of the dielectric substrate is 1mm.

[0033] The material of the dielectric substrate is Arlon AD255A(tm), which has a relative dielectric constant of 2.55 and a loss tangent of 0.0009.

[0034] The high-frequency electromagnetic simulation software HFSS2019 is used to simulate the SIW-based circularly polarized filtering microstrip patch antenna. The parameters after simulation optimization are shown in Table 1 (unit: mm).

[0035] Table 1

[0036] <![CDATA[L g ]]> <![CDATA[L s ]]> <![CDATA[L t ]]> <![CDATA[W m ]]> <![CDATA[W s ]]> 63 44.1 6 16.7 1.2 <![CDATA[p 1 ]]> <![CDATA[p 2 ]]> <![CDATA[p 3 ]]> <![CDATA[p 4 ]]> <![CDATA[p 5 <!-- 3 -->]]> 0.9 1.2 6.7 6.6 3.8 <![CDATA[p6]]> m f s <![CDATA[d1]]> 6.5 6.35 10.5 7.1 0.8 <![CDATA[d2]]> <![CDATA[d3]]> <![CDATA[d4]]> <![CDATA[h1]]> 1.6 1.1 3 1

[0037] Refer to the attached Figure 2 , L g is the side length of the dielectric substrate, L s is the side length of the SIW cavity, L t and W s are the length and width of the rectangular slot, W mis the side length of the microstrip patch, p1 and p2 are the spacing between the cavity columns, p3 is the distance between the disturbance column and the edge of the SIW cavity, p4 and p5 are the distances between the two teams of matching columns, m is the distance between the patch edge close to the substrate edge and the substrate edge, f and s are the distances from the feeding position and the center of the rectangular slot to the SIW cavity edge, d1-d4 are the diameters of the cavity column, matching column, disturbance column and fixing hole, respectively, and h1 is the thickness of the dielectric substrate.

[0038] Figure 3 S is obtained by simulation of the present invention 11 The parameters can realize the curve of gain and AR bandwidth changing with frequency. As shown in the figure, from the simulation results, S 11 The impedance bandwidth below -10dB is 6.9%, the center frequency is 5.125GHz, and the operating frequency ranges from 4.95-5.3GHz; the simulated achievable gain curve shows that the average gain within the band is 8dBi, and the response is flat within the passband. At the same time, there is a radiation zero point at the upper edge and the gain attenuation at the lower edge is also large, which improves the filtering performance of the antenna; the axial ratio bandwidth below 3dB is 4.2%, and the operating frequency ranges from 5GHz to 5.21GHz. Figure 4 (a) and (b) are the left-hand and right-hand circular polarization patterns of the simulated antenna at the minimum axial ratio point of 5.03GHz, respectively. Figure 4 (c) and (d) are the simulated left-hand and right-hand circular polarization patterns of the antenna at the minimum axial ratio point of 5.17 GHz, respectively. It can be seen from the figure that the antenna is left-hand circularly polarized and has good radiation characteristics.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A SIW-based microstrip patch antenna with circular polarization and filter response, characterized by: It includes a SIW cavity structure arranged on a lower layer, and a microstrip patch structure arranged on an upper layer; The SIW cavity structure includes a lower dielectric substrate, a bottom metal floor, a middle metal floor, and four groups of metallized through holes. The bottom metal floor is arranged on the lower surface of the lower dielectric substrate, and the middle metal floor is arranged on the upper surface of the lower dielectric substrate. The four groups of metallized through holes penetrate the lower dielectric substrate, the bottom metal floor, and the middle metal floor, serving as cavity columns to form a square SIW cavity; a pair of metallized through holes is provided at the upper left and lower right corners of the SIW cavity relative to the midline of the feed point, serving as disturbance columns; two pairs of metallized through holes are provided in pairs at the center of the SIW cavity, serving as matching columns; a feeding hole is further provided in the SIW cavity, and the feeding hole is aligned with one of the pairs of matching columns; a rectangular slot is provided on each of the four sides of the SIW cavity; The microstrip patch structure includes an upper dielectric substrate and four square microstrip patches, wherein the four square microstrip patches are orthogonally arranged on the upper surface of the upper dielectric substrate; the lower surface of the upper dielectric substrate is bonded to the middle metal floor.

2. The SIW-based microstrip patch antenna with circular polarization and filtering response according to claim 1, characterized in that: The four square microstrip patches are arranged around the upper dielectric substrate, and the centers of the patches and the centers of the slots in the SIW structure are at the same position.

3. The SIW-based microstrip patch antenna with circular polarization and filtering response according to claim 1, characterized in that: The SIW cavity structure of the lower layer is fitted with the microstrip patch structure of the upper layer up and down, and is fixed by using fixing holes at four corners, which penetrate all layers.

4. The SIW-based microstrip patch antenna with circular polarization and filtering response according to claim 1, characterized in that: Four groups of cavity columns are evenly distributed around the lower dielectric substrate. The side length of the enclosed cavity is 44.1 mm, the diameter of the cavity column is 0.8 mm, and the distance between the cavity columns is 1.2 mm.

5. The SIW-based microstrip patch antenna with circular polarization and filtering response according to claim 1, characterized in that: The diameter of the disturbance column is 1.1 mm, and the shortest distance from the center of the four groups of cavity columns is 6.7 mm.

6. The SIW-based microstrip patch antenna with circular polarization and filtering response according to claim 1, characterized in that: The diameter of the matching column is 1.6 mm, the spacing between a pair of the matching columns on the center line of the feed point is 3.8 mm, and the spacing between a pair of the matching columns on the center line perpendicular to the center line is 6.6 mm.

7. The SIW-based microstrip patch antenna with circular polarization and filtering response according to claim 1, characterized in that: The rectangular groove is 6 mm long, 1.2 mm wide, and 7.1 mm away from the four groups of cavity column edges.

8. The SIW-based microstrip patch antenna with circular polarization and filtering response according to claim 1, characterized in that: The side length of the patch is 16.7 mm, and the distance between the side of the patch close to the edge of the upper dielectric substrate and the edge of the upper dielectric substrate is 6.35 mm.

9. The SIW-based microstrip patch antenna with circular polarization and filtering response according to claim 1, characterized in that: The thickness of the lower dielectric substrate and the upper dielectric substrate are both 1 mm, the side length is 63 mm, the relative dielectric constant is 2.55, and the loss tangent is 0.0015; the diameter of the fixing hole is 6.6 mm, and the distance between the center of the fixing hole and the edges of the two dielectric substrates is 6.5 mm; the shortest distance between the feeding position and the edge of the metallized through hole is 10.5 mm.

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