CN210167507U

CN210167507U - Traffic radar feeder isolation device

Info

Publication number: CN210167507U
Application number: CN201921361493.6U
Authority: CN
Inventors: 倪勇; 陶征; 刘冬
Original assignee: Nanjing Hui Er Looks Intelligent Science And Technology Ltd
Current assignee: Nanjing Hui Er Looks Intelligent Science And Technology Ltd
Priority date: 2019-08-21
Filing date: 2019-08-21
Publication date: 2020-03-20
Anticipated expiration: 2029-08-21
Also published as: WO2021031357A1

Abstract

The utility model belongs to the field of traffic radar feeder isolation, in particular to a traffic radar feeder isolation device, which comprises a feeder metal structural part and a containing cavity, wherein the containing cavity is arranged at the bottom of two side walls and is respectively provided with an inlet and an outlet; the feeder line penetrates into the accommodating cavity from the inlet and penetrates out of the accommodating cavity from the outlet; the cone frustum-shaped metal structural part is provided with a large end face and a small end face, the large end face is connected to the top of the accommodating cavity, and the small end face of the cone frustum-shaped metal structural part faces to the surface where the feeder is located; wherein, there are a plurality of circular cone frustum shape metallic structure spare, and a plurality of circular cone frustum shape metallic structure spare evenly distributed holds the top in chamber. The shielding structure can shield the radiation of the feeder lines and improve the isolation between the feeder lines.

Description

Traffic radar feeder isolation device

Technical Field

The utility model belongs to traffic radar feeder keeps apart the field, concretely relates to traffic radar feeder isolating device.

Background

The frequency band of the traffic radar is 62.2GHz-63.2GHz, and the feeder adopts a coplanar waveguide form, so that the radiation of the feeder in the frequency band is larger, the directional diagram of the antenna is deteriorated, and the performance of the antenna is reduced.

The traffic radar adopts an MIMO antenna, the requirement on the isolation between the feeder lines is high, and important consideration is needed in the design of the feeder lines. The conventional metallic structure can shield the radiation of the feeder lines, but the isolation between the feeder lines is deteriorated. How to effectively shield the feed line radiation and improve the isolation between the feed lines is a main direction of the research of the radar antenna at present.

SUMMERY OF THE UTILITY MODEL

The application provides a traffic radar feeder isolating device, which can shield the radiation of feeders and simultaneously improve the isolation between the feeders.

In order to achieve the technical purpose, the technical scheme adopted by the application is that the traffic radar feeder line isolation device comprises,

the feeder line metal structural part is provided with accommodating cavities which are respectively provided with inlets and outlets and are arranged at the bottoms of the two side walls;

the feeder line penetrates into the accommodating cavity from the inlet and penetrates out of the accommodating cavity from the outlet;

the cone frustum-shaped metal structural part is provided with a large end face and a small end face, the large end face is connected to the top of the accommodating cavity, and the small end face of the cone frustum-shaped metal structural part faces to the surface where the feeder is located;

wherein, there are a plurality of circular cone frustum shape metallic structure spare, and a plurality of circular cone frustum shape metallic structure spare evenly distributed holds the top in chamber.

As the improved technical scheme of this application, hold the height interval 2mm of the least significant end of frustum-shaped metal structure spare and the most significant end of feeder in the chamber.

As an improved technical scheme of the application, the section diameter ratio of the large end face to the small end face of the truncated cone-shaped metal structural part is more than or equal to 1.5.

As the improved technical scheme of the application, the diameter of the large end face of the truncated cone-shaped metal structural part is 1.3mm, and the diameter of the small end face of the truncated cone-shaped metal structural part is 0.7 mm.

As an improved technical scheme of the application, the distance between any two adjacent truncated cone-shaped metal structural parts is not more than 2 mm.

As an improved technical scheme of the application, the rectangular windows of the inlet and the outlet are 28mil by 30 mil.

As an improved technical scheme of the application, an inlet arranged on one side wall of the metal structural member and an outlet arranged on the other side wall of the metal structural member are arranged in a staggered mode.

As an improved technical scheme of the application, the lower end of the side wall of the metal structural part is provided with at least two inlets or at least two outlets.

As an improved technical scheme of the application, the feeder line adopts a coplanar waveguide.

Advantageous effects

The novel metal structural member with the built-in uniform and periodic protruding truncated cone shape is adopted, and the novel metal structural member is covered on the feeder line, so that the isolation between the feeder lines can be improved while the radiation of the feeder lines is shielded; when electromagnetic waves hit the inner wall of the metal, only the inner surface of the metal structural part can form induced current due to skin effect, and the outer surface of the metal structural part cannot generate induced current, so that the metal cavity can shield leakage of the electromagnetic waves; if the inner wall of the cavity is a smooth surface, electromagnetic waves are mainly reflected in the cavity, and the isolation between the feeder lines is deteriorated; after the metal circular truncated cone is added, electromagnetic waves mainly undergo diffuse reflection in the cavity, and only a small amount of electromagnetic waves can affect the feeder lines, so that the isolation between the feeder lines can be optimized while electromagnetic wave leakage is shielded.

What it can realize is the performance of feeder: working frequency band: 62.2GHz-63.2 GHz; voltage standing wave ratio: less than or equal to 1.2; isolation between the feeders: less than or equal to-31 dB; no radiation is emitted outward, and the gain in the pitching direction is-9.78 dBi.

Drawings

FIG. 1 is a schematic view of a feeder model;

FIG. 2 feed line standing wave voltage ratio;

FIG. 3 isolation between feed lines;

FIG. 4 feed line radiation patterns;

FIG. 5 is a cross-sectional view of a feeder line plus a metallic structural member;

FIG. 6 shows the standing wave voltage ratio of the feeder line after the metal structure is added;

FIG. 7 shows the isolation between the feed lines after the metal structure is added;

FIG. 8 is a backfeed radiation pattern of a metallic structure;

FIG. 9 is a cross-sectional view of the present application showing feed line isolation;

FIG. 10 illustrates the voltage ratio of the feeder standing waves of the present application;

FIG. 11 shows the isolation between the feed lines of the present application;

FIG. 12 the present application feed line radiation pattern;

in the figure: 1. a metal structural member; 2. a truncated cone shaped metal structural member; 3. an inlet; 4. and a feeder line.

Detailed Description

In order to make the purpose and technical solution of the embodiments of the present invention clearer, the following description will clearly and completely describe the technical solution of the embodiments of the present invention by combining the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be obtained by a person skilled in the art without any inventive work based on the described embodiments of the present invention, belong to the protection scope of the present invention.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In order to adapt to specific application occasions and ensure the working performance of the radar antenna, the indexes of the traffic radar feeder 4 are generally required to be as follows:

A. working frequency band: 62.2GHz-63.2 GHz;

B. voltage standing wave ratio: less than or equal to 1.2;

C. isolation between the feeders: less than or equal to-30 dB.

In addition, since the antenna is coplanar with and very close to the feeder 4, the feeder 4 is generally required to be free of radiation in order to ensure the performance of the antenna and the pattern index.

A feeder 4 of the traffic radar adopts coplanar waveguide, the model of the feeder 4 is shown in figure 1, the standing wave voltage ratio of the feeder is shown in figure 2, the isolation between the feeders 4 is shown in figure 3, and the radiation direction of the feeder 4 is shown in figure 4.

The performance of the feeder 4 after simulation is shown as follows:

A. working frequency band: 62.2GHz-63.2 GHz;

B. voltage standing wave ratio: less than or equal to 1.16;

C. isolation between the feeders: less than or equal to-34 dB;

D. radiating outward, the gain in elevation is 5.6 dBi.

In the prior art, a metal structural member is added to a feeder 4, specifically: the feeder 4 is covered with a metal structural part 1, the inside of the feeder is hollowed by 4mm, a 28 mil-30 mil rectangular window is formed at the port of the feeder 4, and the specific model is shown in FIG. 5. After simulation, the standing wave voltage ratio of the feeder 4 after the metal structural member 1 is added is shown in fig. 6, the isolation between the feeders 4 after the metal structural member 1 is added is shown in fig. 7, and the radiation pattern 8 of the feeder 4 after the metal structural member 1 is added is shown.

The performance index after simulation shows that the performance of the feeder 4 is as follows:

A. working frequency band: 62.2GHz-63.2 GHz;

B. voltage standing wave ratio: less than or equal to 1.3;

C. isolation between the feeders: less than or equal to-25 dB;

D. without radiating outward, the gain is-9.86 dBi in pitch.

This application is feeder is last 4 to cover novel metal structure 1, and inside is hollowed 4mm and is added even periodic protrusion round platform, and the surface circle diameter is 1.3mm and 0.7mm respectively about the round platform, and the height is 2mm, and two liang of intervals are not more than 2mm, and feeder 4 port department opens 28mil x 30 mil's rectangle window, and concrete model sees figure 9.

Which may be interpreted as a traffic radar feed line 4 isolation device, includes,

the feeder line 4 is a metal structural part 1 which is provided with accommodating cavities at the bottoms of the two side walls and provided with an inlet and an outlet respectively;

the cone frustum-shaped metal structural part 2 is provided with a large end face and a small end face, the large end face is connected to the top of the accommodating cavity, and the small end face of the cone frustum-shaped metal structural part 2 faces the surface where the feeder line 4 is located;

wherein, there are a plurality of circular cone form metallic structure 2, and a plurality of circular cone form metallic structure 2 evenly distributed holds the top in chamber.

The height interval between the lowest end of the frustum-shaped metal structural part 2 in the accommodating cavity and the highest end of the feeder line 4 is 2 mm. If the distance is too small, the truncated cones can generate coupling with the feeder lines 4 to influence the impedance of the feeder lines 4, so that the impedance mismatching deteriorates the performance of the feeder lines 4; if the distance is too large, the whole structural part will rise along with the distance, which will affect the antenna in front of the feeder 4 and deteriorate the directional diagram; the distance of 2mm is a value obtained after the influence of the structural member on the feeder line 4 and the antenna is comprehensively considered and simulation optimization is carried out.

The section diameter ratio of the large end face to the small end face of the truncated cone-shaped metal structural member 2 is not less than 2.5, the selection of the embodiment is 13 (7-1), and in order to reduce the cost on the premise of ensuring the performance, the section diameter ratio of the large end face to the small end face of the truncated cone-shaped metal structural member 2 is 13: 7; therefore, the diameter of the large end face of the frustum-shaped metal structural member 2 in this embodiment is 1.3mm, and the diameter of the small end face thereof is 0.7 mm. If the cost is not considered, and only from the performance perspective, the metal structural part in the shape of the frustum cone is replaced by a cone structure.

In order to realize better performance, the distance between any two adjacent circular truncated cone-shaped metal structural members 2 is not more than 2mm, if the distance is too small, the circular truncated cones can be coupled with the feeder line to influence the impedance of the feeder line 4, so that the impedance mismatch deteriorates the performance of the feeder line 4; if the distance is too large, the whole structure will rise, which will affect the antenna in front of the feed line 4 and deteriorate the pattern. In order to control cost, the distance between any two adjacent truncated cone-shaped metal structural parts 2 is set to be 2mm, meanwhile, rectangular windows of an inlet and an outlet are 28mil multiplied by 30mil, wherein the selected 2mm distance is a value obtained after simulation optimization by comprehensively considering the influence of the structural parts on a feeder line 4 and an antenna; the width of the rectangular window is consistent with that of the coplanar waveguide, the width determination of the coplanar waveguide is from the combination of theoretical calculation and software simulation, and the height value is determined from simulation optimization; a too high rectangular window will result in a partly leaking electromagnetic wave radiated by the feed line 4 deteriorating the antenna pattern.

In order to meet the coplanar waveguide performance of the feeder 4, the inlet 3 arranged on one side wall of the metal structural member is arranged in a staggered manner with the outlet arranged on the other side wall.

In order to meet the requirement that a plurality of feed lines 4 penetrate through, the lower end of the side wall of the metal structural member 1 is provided with at least two inlets or at least two outlets, and in the embodiment, two feed lines 4 are arranged for conveniently and quickly verifying the effect.

After simulation, the standing wave voltage ratio of the feeder 4 is shown in fig. 10, the isolation between the feeders 4 is shown in fig. 11, and the radiation direction of the feeder 4 is shown in fig. 12.

The performance of the specific feeder 4:

A. working frequency band: 62.2GHz-63.2 GHz;

B. voltage standing wave ratio: less than or equal to 1.2;

C. isolation between the feeders: less than or equal to-31 dB;

D. no radiation is emitted outward, and the gain in the pitching direction is-9.78 dBi.

In summary, the following steps: 1. compared with the feeder line 4 without the metal structural part 1, the novel metal structural part 1 with the internally-added convex metal truncated cone can completely shield the radiation of the feeder line 4; 2. compared with the traditional metal structural part 1, the novel metal structural part 1 with the internally-added convex metal truncated cone can completely shield the radiation of the feeder lines 4, and simultaneously, the isolation between the feeder lines 4 is reduced to be below-30 dB.

The above description is only for the embodiments of the present invention, and the description is specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several changes and modifications can be made, which all fall within the scope of the present invention.

Claims

1. The traffic radar feed line isolation device is characterized by comprising

2. A traffic radar feed line isolation device as claimed in claim 1, wherein the height spacing between the lowest end of the frustum-shaped metal structural member in the accommodating cavity and the highest end of the feed line is 2 mm.

3. A traffic radar feed line isolation device as claimed in claim 1, wherein the diameter ratio of the large end face to the small end face of the truncated cone shaped metal structure is greater than or equal to 1.5.

4. A traffic radar feed line isolation device as claimed in claim 1, wherein the diameter of the large end face of the truncated cone shaped metal structure is 1.3mm and the diameter of the small end face is 0.7 mm.

5. A traffic radar feed line isolation device as claimed in claim 1, wherein the spacing between any two adjacent truncated cone shaped metallic structural members is no greater than 2 mm.

6. A traffic radar feed line isolation device as claimed in claim 1, wherein the rectangular windows of the inlet and outlet are 28mil x 30 mil.

7. A traffic radar feed line isolation device as claimed in claim 1, wherein the inlet provided in one side wall of the metallic structural member is offset from the outlet provided in the other side wall.

8. A traffic radar feed line isolation device as claimed in claim 1, wherein the lower end of the side wall of the metallic structural member is provided with at least two inlets or at least two outlets.

9. A traffic radar feed line isolation device as claimed in claim 1, wherein the feed line employs coplanar waveguides.