Millimeter wave broadband circularly polarized filtering antenna

Abstract

The invention relates to a millimeter wave broadband circularly polarized filtering antenna, which belongs to the technical field of wireless energy transmission and comprises an upper dielectric substrate, a lower dielectric substrate, an upper metal floor, a middle metal floor, a lower metal floor, a top patch array, cavity columns and short circuit via holes. The bottom metal floor is arranged on the lower surface of the lower dielectric substrate; the middle-layer metal floor is arranged on the upper surface of the lower-layer dielectric substrate; the upper-layer metal floor is arranged on the lower surface of the upper-layer dielectric substrate; the top-layer patch array is arranged on the upper surface of the upper-layer dielectric substrate; the cavity column penetrates through the middle-layer metal floor, the lower-layer dielectric substrate and the bottom-layer metal floor to define an I-shaped SIW cavity; a feed hole is formed in the I-shaped SIW cavity; the short-circuit via hole penetrates through the top-layer patch array, the upper-layer dielectric substrate and the upper-layer metal floor; and two same rectangular coupling grooves are respectively etched in the middle parts of the upper-layer metal floor and the middle-layer metal floor.

Description

Technical Field

[0001] The invention belongs to the technical field of wireless energy transmission and relates to a millimeter wave broadband circular polarization filtering antenna. Background Art

[0002] Driven by 5G and IoT applications, the demand for high-speed wireless communication systems is growing rapidly, and therefore the demand for millimeter wave antennas is also increasing. However, wireless communication in the millimeter wave frequency band is susceptible to path loss, multipath interference, and polarization mismatch.

[0003] In order to solve these problems, circularly polarized antennas with filtering characteristics are used in millimeter wave communications. Millimeter wave circularly polarized antennas can effectively suppress interference from adjacent frequency bands while maintaining their circular polarization characteristics. At present, many millimeter wave circularly polarized antennas use SIW technology, which has the advantages of easy integration, low loss, and high reliability. In addition, in most millimeter wave circularly polarized antennas, circular polarization can be achieved through various technologies, including the use of sequential rotating feeds, dedicated circularly polarized structures, 90° SIW directional couplers, etc. However, most of the current millimeter wave circularly polarized antennas lack certain filtering performance, and due to the needs of broadband communication systems, the axial ratio bandwidth of millimeter wave antennas needs to be further broadened. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a millimeter wave broadband circular polarization filtering antenna with three controllable radiation zero points to achieve a good filtering effect. Three left-handed circular polarization axis ratio points are generated to achieve a larger axis ratio bandwidth. The antenna has a simple structure and is easy to integrate, while reducing the manufacturing cost of the antenna and facilitating processing and manufacturing.

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

[0006] A millimeter wave broadband circular polarization filtering antenna comprises an upper dielectric substrate, a lower dielectric substrate, an upper metal floor, a middle metal floor, a lower metal floor, a top patch array, a cavity column and a short-circuit via; the bottom metal floor is arranged on the lower surface of the lower dielectric substrate; the middle metal floor is arranged on the upper surface of the lower dielectric substrate; the upper metal floor is arranged on the lower surface of the upper dielectric substrate; the top patch array is arranged on the upper surface of the upper dielectric substrate; the cavity column passes through the middle metal floor, the lower dielectric substrate and the bottom metal floor to form an "I"-shaped SIW cavity; a feeding hole is provided in the "I"-shaped SIW cavity; the short-circuit via passes through the top patch array, the upper dielectric substrate and the upper metal floor; two identical rectangular coupling slots are etched in the middle of the upper metal floor and the middle metal floor respectively.

[0007] Furthermore, the top-level patch array includes four identical square patches; the square patches are etched with a first rectangular groove along a group of diagonals, and the square patches are etched with a second rectangular groove along another group of diagonals; the first rectangular groove is longer and narrower than the second rectangular groove; an L-shaped branch is respectively provided on two adjacent sides of the square patch; the two sides of the four square patches without L-shaped branches are connected in pairs to form a square top-level patch array; the first rectangular grooves of the four square patches are parallel, and the second rectangular grooves of the four square patches are parallel.

[0008] Furthermore, there are four short-circuit vias in total, which respectively penetrate through the four square patches and the upper dielectric substrate and the upper metal floor.

[0009] Furthermore, the "I"-type SIW cavity includes an upper rectangular cavity, a middle rectangular cavity and a lower rectangular cavity; the upper rectangular cavity is L1 long and W1 wide; the middle rectangular cavity is L2 long and W2 wide; the lower rectangular cavity is L3 long and W3 wide; wherein L1>L3>L2, W1>W2>W3.

[0010] Furthermore, the center distance of the cavity columns at the bottom side of the lower rectangular cavity is smaller than the center distance of the other cavity columns in the "I"-type SIW cavity.

[0011] The beneficial effects of the present invention are: the SIW resonant cavity is combined with the patch, the cavity and the patch are connected by a short-circuit column, the antenna excites the cavity in a bottom-fed manner, and the cavity excites the patch array through the top rectangular slot to achieve good radiation effect and filtering performance. The design of the antenna is conducive to further research in the field of millimeter wave circular polarization. It can be applied to the research and design of 5G communication systems. The antenna uses the I-type SIW cavity structure to realize three independently controllable radiation zero points, so that the antenna obtains a better filtering effect. The short-circuit columns arranged regularly on the upper layer produce a left-handed axial ratio extreme point, and the top square patch etched with a cross groove introduces two axial ratio extreme points for the antenna, and finally achieves a larger axial ratio bandwidth. The -10dB impedance bandwidth of this antenna ranges from 23.9 to 26.97GHz, and the 3dB axial ratio bandwidth ranges from 24.24 to 26.97GHz, which can achieve a peak gain of 10.6dBi. This antenna has the characteristics of easy integration, low loss, high reliability, simple structure, low manufacturing cost, and easy processing and manufacturing, and has certain engineering use value.

[0012] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] 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 in conjunction with the accompanying drawings, wherein:

[0014] Figure 1 This is a schematic diagram of the structure of the millimeter wave broadband circularly polarized filter antenna of the present invention;

[0015] Figure 2 This is a schematic diagram of the dimensions of the millimeter wave broadband circularly polarized filtering antenna of the present invention;

[0016] Figure 3 The millimeter wave broadband circularly polarized filtering antenna S of the present invention 11 Parameters, achievable gains;

[0017] Figure 4 The axial ratio bandwidth of the millimeter wave broadband circularly polarized filtering antenna of the present invention;

[0018] Figure 5 : The radiation pattern of the millimeter wave broadband circularly polarized filter antenna at the axis ratio point of the present invention; wherein (a) is the E plane and (b) is the H plane;

[0019] Figure numerals: bottom metal floor 1, lower dielectric substrate 2, middle metal floor 3, upper metal floor 4, upper dielectric substrate 5, top patch array 6, cavity column 7, feeding hole 8, cross slot 9, short-circuit via 10, rectangular coupling slot 11. DETAILED DESCRIPTION

[0020] The following describes the embodiments of the present invention by 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 only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0021] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0022] 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 the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position 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.

[0023] See attached Figure 1 The present invention provides a millimeter-wave broadband circularly polarized filtering antenna, which includes a bottom metal floor 1, a bottom dielectric substrate 2, a middle metal floor 3, an upper metal floor 4, an upper dielectric substrate 5, a top patch array 6, a cavity column 7, a feeding hole 8, a cross-shaped slot 9, a short-circuit via 10, and a rectangular coupling slot 11. The bottom metal floor 1 is arranged on the lower surface of the lower dielectric substrate 2, the middle metal floor 3 is arranged on the upper surface, the upper metal floor 4 is arranged on the lower surface of the upper dielectric substrate 5, and the top patch array 6 is arranged on the upper surface. The cavity column 7 penetrates the bottom metal floor 1, the bottom dielectric substrate 2, and the middle metal floor 3. A feeding hole 8 is arranged on the bottom metal floor 1. A cross-shaped slot 9 is etched on the top patch array 6. A short-circuit via 10 penetrates the top patch array 6, the upper dielectric substrate 5, and the upper metal floor 4. A rectangular coupling slot 11 is arranged on the middle metal floor 3 and the upper metal floor 4.

[0024] The three metal floors are the same size as the two dielectric substrates, with a length of 24 mm and a width of 18.8 mm. The length of the long cross slot is 6.2 mm and the width is 0.2 mm, and the length of the short slot is 4.3 mm and the width is 0.3 mm. The diameter of the four short-circuit vias is 1.2 mm. The diameter of the cavity column is 1.2 mm. The length of the rectangular coupling slot is 3.6 mm and the width is 0.5 mm.

[0025] The material of the dielectric substrate is Rogers RT / duroid 5880(tm), with a relative dielectric constant of 2.22 and a loss tangent of 0.0009.

[0026] The millimeter-wave broadband circularly polarized filter antenna is simulated using high-frequency electromagnetic simulation software HFSS2022, and the parameters after simulation optimization are shown in Table 1 (in mm).

[0027] Table 1

[0028] <![CDATA[W1]]> <![CDATA[W2]]> <![CDATA[W3]]> <![CDATA[W4]]> <![CDATA[W5]]> 1.2 1.6 0.2 0.3 0.2 <![CDATA[W6]]> <![CDATA[W7]]> <![CDATA[W8]]> <![CDATA[W9]]> <![CDATA[W 10 ]]> 15.3 6.2 0.5 11.1 6.58 <![CDATA[W 11 ]]> <![CDATA[L1]]> <![CDATA[L2]]> <![CDATA[L3]]> <![CDATA[L4]]> 0.34 4.1 1.3 5.8 6.2 <![CDATA[L5]]> <![CDATA[L6]]> <![CDATA[L7]]> <![CDATA[L8]]> <![CDATA[d1]]> 4.3 4.75 4.62 3.6 1.2 <![CDATA[d2]]> <![CDATA[d3]]> <![CDATA[P1]]> <![CDATA[P2]]> <![CDATA[H1]]> 1.2 0.52 1.5 1.4 0.508 <![CDATA[H2]]> 0.787

[0029] See attached Figure 2 , W1-W2 is the width of the L-shaped branch of the top-layer patch matrix, W3-W4 are the widths of the long and short grooves of the cross-shaped slot, W5 is the spacing between the four square patches of the top-layer patch matrix, L1-L2 are the lengths of the L-shaped branch of the top-layer patch matrix, L3 is the side length of the four square patches of the top-layer patch matrix, L4-L5 are the lengths of the long and short grooves of the cross-shaped slot, L6-L7 are the spacing between the two short-circuit vias, d1 is the diameter of the short-circuit via, W6-W7 and W9-W 10 are the longest center distances of the cavity columns on each side of the I-type SIW cavity, W8 is the width of the rectangular coupling slot, L8 is the length of the rectangular coupling slot, P1-P2 are the center distances of the cavity columns, d2 is the diameter of the cavity column, H1 is the thickness of the upper dielectric substrate, and H2 is the thickness of the lower dielectric substrate.

[0030] Figure 3 S is obtained by simulation of the present invention. 11 The parameters can realize the curve graph of gain changing with frequency. As shown in the figure, from the simulation results, S 11 The -10dB impedance bandwidth ranges from 23.9 to 26.97GHz; the simulated achievable gain curve shows that the achievable gain in the band can reach up to 10.6dBi, and the response is flat in the passband. At the same time, there are three controllable radiation zero points, which improves the filtering performance of the antenna. Figure 4 This is a curve diagram of the axial ratio changing with frequency obtained by simulation of the present invention. From the simulation results, it can be seen that the axial ratio bandwidth of 3dB axial ratio is 11.2% (24.24-26.97GHz). Figure 5 (a)-(b) are the axial ratio point simulation radiation patterns of the present invention at 25.8 GHz. From the simulation results, it can be seen that the antenna has good broadside radiation characteristics.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. 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 solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A millimeter wave broadband circularly polarized filtering antenna, characterized in that: It includes an upper dielectric substrate, a lower dielectric substrate, an upper metal floor, a middle metal floor, a lower metal floor, a top patch array, a cavity column and a short-circuit via; the bottom metal floor is arranged on the lower surface of the lower dielectric substrate; the middle metal floor is arranged on the upper surface of the lower dielectric substrate; the upper metal floor is arranged on the lower surface of the upper dielectric substrate; the top patch array is arranged on the upper surface of the upper dielectric substrate; the cavity column passes through the middle metal floor, the lower dielectric substrate and the bottom metal floor to form an "I"-shaped SIW cavity; a feeding hole is provided in the "I"-shaped SIW cavity; the short-circuit via passes through the top patch array, the upper dielectric substrate and the upper metal floor; two identical rectangular coupling grooves are etched in the middle of the upper metal floor and the middle metal floor respectively.

2. The millimeter wave broadband circularly polarized filtering antenna according to claim 1, characterized in that: The top-layer patch array includes four identical square patches; the square patches are etched with a first rectangular groove along a group of diagonals, and the square patches are etched with a second rectangular groove along another group of diagonals; the first rectangular groove is longer and narrower than the second rectangular groove; an L-shaped branch is respectively provided on two adjacent sides of the square patch; the two sides of the four square patches without L-shaped branches are connected in pairs to form a square top-layer patch array; the first rectangular grooves of the four square patches are parallel, and the second rectangular grooves of the four square patches are parallel.

3. The millimeter wave broadband circularly polarized filtering antenna according to claim 1, characterized in that: There are four short-circuit vias in total, which respectively penetrate through four square patches and the upper dielectric substrate and the upper metal floor.

4. The millimeter wave broadband circularly polarized filtering antenna according to claim 1, characterized in that: The "I"-type SIW cavity includes an upper rectangular cavity, a middle rectangular cavity and a lower rectangular cavity; the upper rectangular cavity is L1 long and W1 wide; the middle rectangular cavity is L2 long and W2 wide; the lower rectangular cavity is L3 long and W3 wide; wherein L1>L3>L2, W1>W2>W3.

5. The millimeter wave broadband circularly polarized filtering antenna according to claim 1, characterized in that: The center distance of the bottom cavity columns of the lower rectangular cavity is smaller than the center distance of the other cavity columns in the "I" type SIW cavity.

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