CN109904613B

CN109904613B - Differential dual-frequency dual-polarized filtering antenna applied to 5G Sub 6GHz base station system

Info

Publication number: CN109904613B
Application number: CN201910122093.8A
Authority: CN
Inventors: 李亚鹏; 赵志鹏; 唐朝阳; 尹应增
Original assignee: Xian University of Electronic Science and Technology
Current assignee: Xian University of Electronic Science and Technology
Priority date: 2019-02-19
Filing date: 2019-02-19
Publication date: 2020-02-07
Anticipated expiration: 2039-02-19
Also published as: CN109904613A

Abstract

The invention discloses a differential double-frequency dual-polarized filter antenna applied to a 5G Sub 6GHz base station system, which comprises an upper medium substrate, a lower medium substrate and four metal columns connected with the upper medium substrate and the lower medium substrate, wherein a metal radiation patch is arranged on the upper medium substrate 1, a metal floor 25 is arranged on the upper surface of the lower medium substrate, and a metal feeder line is printed on the lower surface of the lower medium substrate; gain double-frequency filtering characteristics are obtained by slotting the metal radiation patch and introducing a stepped impedance type open-circuit branch on the metal feeder line. The invention has the advantages of simple structure, easy processing, wider resonance bandwidth in a radiation frequency band, better double-frequency filter response, stable gain and directional diagram, lower cross polarization, higher port isolation, easy integration with a differential circuit and the like. The antenna can be used for a 5G Sub 6GHz base station communication system, and is particularly suitable for a +/-45-degree dual-polarized base station antenna system with two frequency bands of 3.3GHz-3.6GHz and 4.8GHz-5.0 GHz.

Description

Differential dual-frequency dual-polarized filtering antenna applied to 5G Sub 6GHz base station system

Technical Field

The invention relates to a differential double-frequency dual-polarized filtering antenna applied to a 5G Sub 6GHz base station system, which works at 3.23GHz-3.67GHz and 4.76GHz-5.13GHz and can be used in the 5G base station system.

Background

The performance index of the base station antenna, which is the frontmost end of the receiving and transmitting of the wireless communication system, is directly related to the quality of the wireless communication, and as the requirements of the wireless communication system on the antenna are higher and higher, the design trend of the antenna is developing towards miniaturization, arraying, low profile, multi-frequency/broadband, and stable gain and directional diagram characteristics, high out-of-band rejection characteristics, and excellent isolation are also used as important indexes of the antenna performance. The general dual-polarized antenna has poor out-of-band rejection characteristics outside the working bandwidth, the gain of the multi-frequency antenna and the stability of a directional diagram are also poor, and the isolation of two groups of polarized ports is low.

Disclosure of Invention

In order to solve the problems, the differential double-frequency dual-polarization filtering antenna applied to a 5G Sub 6GHz base station system is provided, the antenna obtains the double-frequency filtering characteristic of gain by a method of slotting on a radiating body and introducing a stepped impedance type open-circuit branch on a feeder line, and can obtain better standing wave, gain and directional diagram characteristics while covering two frequency bands of 3.3GHz-3.6GHz and 4.8GHz-5.0GHz of 5G communication, so that the antenna can be applied to the 5G Sub 6GHz base station system.

The invention is realized by the following technical scheme.

A differential double-frequency dual-polarization filter antenna applied to a 5G Sub 6GHz base station system comprises an upper medium substrate, a lower medium substrate and four metal columns connected with the upper medium substrate and the lower medium substrate, wherein a metal radiation patch is arranged on the upper medium substrate, a metal floor is arranged on the upper surface of the lower medium substrate, and a metal feeder line is printed on the lower surface of the lower medium substrate; and a groove is formed in the metal radiation patch, and a stepped impedance type open-circuit branch is introduced to the metal feeder line, so that the gain double-frequency filtering characteristic is obtained.

With respect to the above technical solutions, the present invention has a further preferable solution:

further, the metal radiation patch is arranged on the upper surface of the upper-layer medium substrate.

Furthermore, rectangular grooves are etched on the periphery of the metal radiation patch, a cross-shaped upper metal patch slot is etched in the center of the metal radiation patch, and four metal patches on the upper surface of the upper medium substrate are respectively printed in the slots corresponding to the upper metal patch.

Furthermore, a metal floor is printed on the upper surface of the lower medium substrate, and four circular holes communicated with corresponding holes of the lower medium substrate are etched on the metal floor.

Further, a metal feeder is printed on the lower surface of the lower-layer medium substrate; the metal feeder line is provided with stepped impedance type open-circuit branches which are respectively vertical to the metal micro-strip feeder line and symmetrically distributed, and are bent towards two symmetrical sides at the extension section, and the bending sections on the same rectangular side are mutually distributed in parallel.

Furthermore, the tail end of the metal feeder printed on the lower surface of the lower dielectric substrate can be connected with a coaxial cable or an SMA adapter for feeding.

Furthermore, the upper ends of the metal columns are respectively connected with the metal patches through the upper-layer dielectric substrate, and the lower ends of the metal columns are respectively connected with the front ends of the metal feeders through floor etching circular holes in the metal floor.

Further, the metal patch is an aluminum plate or a copper plate.

The active standing wave of the differential dual-frequency dual-polarized filter antenna is less than 1.5, the impedance bandwidth is 12.8% at 3.23-3.67GHz and is 7.5% at 4.76-5.13 GHz; the gain of the antenna is 8.95 +/-0.39 dBi at the low frequency band and 9.97 +/-0.33 dBi at the high frequency band.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

1. the square patch with the slots at the symmetrical edges and the stepped impedance type open-circuit branch are adopted, three radiation zero points are generated outside a working frequency band, a good filtering effect is formed, and the problem of electromagnetic interference in a multi-antenna system can be well solved.

2. Besides generating a radiation zero point, the stepped impedance type open-circuit branch also obviously improves the impedance matching of two frequency bands, widens the working bandwidth of the dual-frequency antenna, and meets the requirements of the 5G base station application on the working frequency bands (3.3GHz-3.6GHz and 4.8GHz-5.0 GHz).

3. Because the antenna in the invention adopts a differential feed mode, the port isolation degree higher than 41dB is obtained, and the integrated design with a differential circuit is convenient.

4. The antenna has the advantages of simple structure, easy processing, low profile, small volume, light weight, low cost and the like.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention:

fig. 1 is a perspective view of an antenna of the present invention;

FIG. 2 is a cross-sectional side view of the present invention;

FIG. 3 is a top plan view of the present invention;

FIG. 4 is a bottom plan view of the base layer of the present invention;

FIG. 5 is a top plan view of the upper surface of a lower dielectric slab of the present invention;

FIG. 6 is a graph of the active standing wave of the antenna of the present invention;

FIG. 7 is a graph of the gain of the antenna of the present invention;

FIG. 8 is a port isolation simulation for an antenna of the present invention;

FIG. 9 is a radiation pattern of the present invention operating at 3.5 GHz;

FIG. 10 is a radiation pattern of the present invention operating at 4.9 GHz;

fig. 11 is a graph of the efficiency of the antenna of the present invention.

In the figure: 1. an upper dielectric substrate; 2. a metal radiation patch; 3. 4, 5 and 6, metal patch; 7. 8, 9 and 10, rectangular slots; 11. 12, 13, 14, metal posts; 15. 16, 17, 18, metal feed lines; 19. 20, 21, 22, etching a circular hole on the floor; 23. slotting the upper metal patch; 24. a lower dielectric substrate; 25. a metal floor.

Detailed Description

The present invention will now be described in detail with reference to the drawings and specific embodiments, wherein the exemplary embodiments and descriptions of the present invention are provided to explain the present invention without limiting the invention thereto.

As shown in fig. 1 and 2, the differential dual-frequency dual-polarization filtering antenna applied to a 5G Sub 6GHz base station system of the present invention includes an upper dielectric substrate 1, a lower dielectric substrate 24, and four

metal columns

11, 12, 13, 14 connecting the upper dielectric substrate 1 and the lower dielectric substrate 24, wherein the upper dielectric substrate 1 is provided with a metal radiation patch 2, the upper surface of the lower dielectric substrate 24 is provided with a metal floor 25, and the lower surface of the lower dielectric substrate 24 is printed with metal feeders 15, 16, 17, 18; gain double-frequency filtering characteristics are obtained by slotting the metal radiation patch 2 and introducing stepped impedance type open-circuit branches on the metal feeder line.

As shown in fig. 3, a rectangular metal radiation patch 2 is disposed on the upper surface of the upper dielectric substrate 1,

rectangular grooves

7, 8, 9, and 10 are etched around the metal radiation patch 2, a cross-shaped upper metal patch slot 23 is etched in the center of the metal radiation patch 2, four metal patches 3, 4, 5, and 6 are respectively printed in the corresponding upper metal patch slot 23, and the four metal patches 3, 4, 5, and 6 are disposed on the upper surface of the upper dielectric substrate 1.

As shown in fig. 4 and 5, a metal floor 25 is printed on the upper surface of the lower dielectric substrate 24, four

circular holes

19, 20, 21 and 22 are etched on the metal floor 25, and the lower dielectric substrate 24 is perforated at positions corresponding to the four

circular holes

19, 20, 21 and 22; the metal feed lines 15, 16, 17, 18 are printed on the lower surface of the lower dielectric substrate 24. The metal feeder lines 15, 16, 17 and 18 are stepped impedance open-circuit branches which are respectively vertical to the metal microstrip feeder lines and symmetrically distributed, and are bent towards two symmetrical sides at the extension section, and the bent sections at the same rectangular side are mutually distributed in parallel. And the metal feed lines 15, 18, 17 and 16 printed on the lower surface of the lower dielectric substrate 24 can be connected with coaxial cables or SMA adaptor at the tail ends for feeding.

The upper ends of the

metal posts

11, 12, 13, 14 are respectively connected with the metal patches 5, 6, 3, 4 through the upper dielectric substrate 1, and the lower ends thereof are respectively connected with the front ends of the metal patches 15, 18, 17, 16 through the floor etching

circular holes

19, 22, 21, 20 on the metal floor 25. Preferably, the metal patch is an aluminum plate or a copper plate.

An example is given below. The metal floor is 55mm long and 55mm wide, and the height of the air gap between the upper and lower dielectric substrates is 10 mm. The dielectric constant of the upper dielectric substrate 1 is 2.65, the length of the upper dielectric substrate is 55mm, the width of the upper dielectric substrate is 55mm, and the thickness of the upper dielectric substrate is 0.5 mm. The square metal radiating patch 2 has a side length of 27.2 mm. The width of the rectangular groove is 1.0mm, the length of the rectangular groove is 25mm, and the distance between the rectangular groove and the edge of the square metal radiation patch is 0.1 mm. The metal patches 3, 4, 5 and 6 are 4.6mm long and 2.3mm wide, and the gap interval between the metal patches and the metal patches is 0.6 mm. The dielectric constant of the lower dielectric substrate 24 is 2.65, the length of the lower dielectric substrate is 55mm, the width of the lower dielectric substrate is 55mm, the thickness of the lower dielectric substrate is 0.8 mm, the upper surface of the lower dielectric substrate is a metal floor, and the radius of four middle holes is 1 mm. The sizes of the stepped impedance type open-circuit branch knots are respectively as follows: the width of the low-impedance line is 1.1mm, the length of the low-impedance line is 13mm, the width of the high-impedance line is 0.2mm, and the length of each side is 21.5 mm. The width of the 50 ohm microstrip feed line connected with the microstrip feed line is 2.14 mm.

And finally welding the outer skin of the SMA connector to the metal grounding plate, welding the inner core to the metal feed wire, and feeding the differential signal into the two centrosymmetric ports. The differential double-frequency dual-polarized filtering antenna applied to the 5G Sub 6GHz base station system is completed.

The invention can be further illustrated by the following simulations:

1. emulated content

Simulation software is utilized to carry out simulation calculation on the standing wave curve, the gain curve, the port isolation degree, the far-field radiation pattern and the radiation efficiency of the differential double-frequency dual-polarized filter antenna applied to the 5G Sub 6GHz base station system.

2. Simulation result

Fig. 6 is a graph showing the standing wave of the antenna of the present invention. It can be seen that the impedance bandwidth of the bandwidth with the active voltage standing wave ratio of less than 1.5 of the antenna is 12.8% at 3.23-3.67GHz and 7.5% at 4.76-5.13GHz, and the antenna can cover a wider 5GSub 6GHz communication frequency band.

Fig. 7 is a gain variation curve of the present antenna. It can be seen that the gain of the antenna is 8.95 +/-0.39 dBi at the low frequency band and 9.97 +/-0.33 dBi at the high frequency band, and stable gain is realized in both the two frequency bands. In addition, gain fading is obvious outside two frequency bands, and a good filtering effect is formed.

Fig. 8 shows port isolation of the antenna in the operating band. It can be seen that the isolation of the antenna of the invention reaches more than 41dB in two frequency bands, and the port isolation requirement of the base station antenna system is better satisfied.

Fig. 9 and 10 are the radiation diagrams of the antenna at the frequency of 3.5GHz and 4.9GHz, respectively. Because the feeding port is diagonally and differentially fed, the polarization form of the antenna in the invention is dual polarization of +/-45 degrees, and horizontal and vertical polarization components of the antenna need to be tested in practical application. It can be seen from the figure that the antenna has a stable directional diagram, low cross polarization and high front-to-back ratio in the working frequency band.

Fig. 11 is a radiation efficiency diagram of an antenna. It can be seen that the antenna radiation efficiency is not less than 95% in both operating bands. Outside the two working frequency bands, the radiation efficiency of the antenna is lower than 15%, and a good out-of-band inhibition effect is obtained.

The present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.

Claims

1. The differential double-frequency dual-polarization filter antenna applied to a 5G Sub 6GHz base station system is characterized by comprising an upper-layer dielectric substrate (1), a lower-layer dielectric substrate (24) and four metal columns (11, 12, 13 and 14) connected with the upper-layer dielectric substrate (1) and the lower-layer dielectric substrate (24), wherein a metal radiation patch (2) is arranged on the upper-layer dielectric substrate (1), a metal floor (25) is arranged on the upper surface of the lower-layer dielectric substrate (24), and metal feeders (15, 16, 17 and 18) are printed on the lower surface of the lower-layer dielectric substrate (24); a groove is formed in the metal radiation patch (2) and a stepped impedance type open-circuit branch is introduced to the metal feeder line, so that the dual-frequency filter characteristic of the gain is obtained;

rectangular grooves (7, 8, 9 and 10) are etched on the periphery of the metal radiation patch (2), a cross-shaped upper metal patch slot (23) is etched in the center of the metal radiation patch (2), and four metal patches (3, 4, 5 and 6) on the upper surface of the upper medium substrate (1) are printed in the corresponding upper metal patch slot (23) respectively.

2. The differential dual-frequency dual-polarization filtering antenna applied to a 5G Sub 6GHz base station system is characterized in that the metal radiating patch (2) is arranged on the upper surface of the upper dielectric substrate (1).

3. The differential double-frequency dual-polarization filtering antenna applied to a 5G Sub 6GHz base station system is characterized in that a metal floor (25) is printed on the upper surface of the lower dielectric substrate (24), and four circular holes (19, 20, 21, 22) which are communicated with corresponding holes of the lower dielectric substrate (24) are etched in the metal floor (25).

4. A differential dual-frequency dual-polarized filter antenna applied to a 5G Sub 6GHz base station system according to claim 3, wherein the lower surface of the lower dielectric substrate (24) is printed with metal feeder lines (15, 16, 17, 18); the metal feeder lines (15, 16, 17 and 18) are provided with stepped impedance type open-circuit branches which are respectively vertical to the metal microstrip feeder lines and symmetrically distributed, and are bent towards two symmetrical sides at the extension section, and the bent sections at the same rectangular side are mutually distributed in parallel.

5. A differential double-frequency dual-polarized filtering antenna applied to a 5G Sub 6GHz base station system according to claim 4, characterized in that the metal microstrip feed lines (15, 18, 17, 16) printed on the lower surface of the lower dielectric substrate (24) are connected with coaxial cables or SMA adaptor at the tail ends for feeding.

6. A differential dual-frequency dual-polarization filtering antenna applied to a 5G Sub 6GHz base station system according to any one of claims 1-5, characterized in that the upper ends of the metal posts (11, 12, 13, 14) are respectively connected with the metal patches (5, 6, 3, 4) through the upper dielectric substrate (1), and the lower ends thereof are respectively connected with the front ends of the metal feeder lines (15, 18, 17, 16) through floor-etched circular holes (19, 22, 21, 20) on the metal floor (25).

7. The differential dual-frequency dual-polarization filtering antenna applied to a 5G Sub 6GHz base station system according to claim 6, wherein the metal patch is an aluminum plate or a copper plate.

8. The differential dual-frequency dual-polarized filtering antenna applied to a 5G Sub 6GHz base station system according to claim 1, wherein the impedance bandwidth of the active standing wave of the differential dual-frequency dual-polarized filtering antenna less than 1.5 is 12.8% at 3.23-3.67GHz and 7.5% at 4.76-5.13 GHz; the gain of the antenna is 8.95 +/-0.39 dBi at the low frequency band and 9.97 +/-0.33 dBi at the high frequency band.