CN109546348B

CN109546348B - Novel miniaturized broadband SW-SIW horn antenna and design method thereof

Info

Publication number: CN109546348B
Application number: CN201811420295.2A
Authority: CN
Inventors: 黄鹏; 李良荣; 金海焱
Original assignee: Guizhou University
Current assignee: Guizhou University
Priority date: 2018-11-26
Filing date: 2018-11-26
Publication date: 2020-08-25
Anticipated expiration: 2038-11-26
Also published as: CN109546348A

Abstract

The invention discloses a novel miniaturized broadband SW-SIW horn antenna and a design method thereof. The top metal plate and the bottom metal plate are provided with the same periodic grooves, and coupling capacitance is generated between the upper groove and the lower groove, so that the electrical property parameters of the dielectric substrate can be influenced, the propagation constant and the impedance characteristic of the dielectric layer are changed, the propagation of electromagnetic waves is further influenced, and the slow wave characteristic is formed. The two slow wave structures formed by the slots enable electromagnetic waves to be converted from spherical waves into plane waves at the radiation port of the horn antenna, the width of a radiation lobe is reduced, and the radiation efficiency of the antenna is effectively improved. Compared with the traditional horn antenna, the invention has the advantages of good directivity, wider frequency band, higher gain, greatly improved radiation efficiency, low section, small size, lower connection loss with a planar circuit, easier integration realization, simple structure, easy processing and lower engineering application cost.

Description

Novel miniaturized broadband SW-SIW horn antenna and design method thereof

Technical Field

The invention belongs to the technical field of microwave antenna engineering, can be widely applied to interplanetary communication, 5G (5th-generation) communication and millimeter wave communication, and particularly relates to an H-plane horn antenna of a miniaturized broadband slow-wave Substrate Integrated Waveguide (SW-SIW) technology.

Background

With the advent of the new generation of wireless communication technology, the entire international society is increasing the effort to build a new generation of communication infrastructure and to develop a new generation of communication technology and novel microwave devices. New generation communication systems also place higher demands on the performance and integration of microwave devices. The antenna is the most critical component of the communication system, and has wide application in the fields of daily life, aerospace, interplanetary communication and the like. It becomes important to realize antenna broadband communication and miniaturization.

Compared with the traditional microstrip antenna, the horn antenna has a simpler structure and a convenient feed mode. Moreover, the horn antenna can realize high-frequency communication, and has the advantages of wide frequency band, strong directivity, high gain and the like. However, compared with the conventional microstrip antenna, the horn antenna has a large size, occupies a large space and is difficult to integrate, and the horn antenna is connected to a circuit system in a conventional coaxial transition mode and often generates large insertion loss.

Substrate Integrated Waveguide (SIW) technology, SIW and conventional rectangular metal waveguides have similar quasi-closed planar Waveguide structures and have good transmission characteristics. In addition, the substrate integrated waveguide is processed by a standard PCB process, and has the characteristics of high Q value, easiness in processing and integration, light weight, small size and the like. A substrate integrated waveguide is also a waveguide structure whose cut-off frequency is mainly determined by the bandwidth, and the physical size of the SIW is still large compared to coplanar waveguides and microstrip circuits. The Slow Wave (SW) structure is applied to the traveling Wave tube for the first time, so that the speed of the electromagnetic Wave propagating through the Slow Wave structure can be reduced, and the wavelength of the electromagnetic Wave corresponding to the Slow Wave structure is reduced. The SW structure allows the physical size of the antenna to be further reduced, since the size of the antenna is also related to the wavelength of the electromagnetic wave. Therefore, the miniaturized broadband SW-SIW horn antenna has long-term scientific significance and practical application value in the application of the wireless communication field.

Disclosure of Invention

The purpose of the invention is: the novel miniaturized broadband SW-SIW horn antenna has the advantages of wide frequency band, high gain, good directivity, greatly improved radiation efficiency, reduced size, easy integration, simple structure and low application cost.

The invention is realized by the following steps: the miniaturized broadband SW-SIW horn antenna comprises a dielectric layer, wherein a top metal layer is arranged on the top surface of the dielectric layer, a bottom metal layer is arranged on the bottom surface of the dielectric layer, and a microstrip line structure and a transition structure of SIW-to-microstrip are arranged at the front end of the top metal layer; grooves with corresponding positions and shapes are formed in the middle positions of the top metal layer and the bottom metal layer to form a slow-wave structure A and a slow-wave structure B, and the grooves forming the slow-wave structure A and the slow-wave structure B are symmetrical along the central axis of the dielectric layer and are distributed periodically; the front-end metal cylinder and the guide metal cylinder are arranged on the dielectric layer and are symmetrical along the central axis, and both the front-end metal cylinder and the guide metal cylinder penetrate through the dielectric layer and are connected with the top metal layer and the bottom metal layer, so that the top metal layer is electrically connected with the bottom metal layer; the front end metal cylinders are arranged in parallel at two sides of the front end of the dielectric layer and form equivalent rectangular waveguides, and the guide metal cylinders are positioned at the tail ends of the front end metal cylinders and distributed in a step shape along the opening angles of the edges of the two sides of the dielectric layer. The guide metal cylinder is mainly used for realizing better impedance matching of the antenna, so that the horn antenna keeps better directivity, the gain and the radiation efficiency of the antenna are improved, and the performance of the antenna is further improved.

In the front-end metal cylinder and the guide metal cylinder, the distance p between adjacent metal cylinders meets lambda_c/4>p>λ_c/20 diameter of metal cylinder d₁Satisfy d₁<p<2.5d₁Wherein λ is_cIs the cutoff wavelength for the main mode transmission of SIW.

The ends of the top metal layer and the bottom metal layer are respectively provided with a rectangular array, and the upper and lower groups of rectangular arrays are vertically symmetrical and form a dipole array together. By loading the dipole array, the gain of the antenna is improved, the radiation energy is more concentrated, the directivity of the antenna is improved, and the radiation efficiency and the performance of the antenna are further improved.

By adopting the technical scheme, the inventor of the invention finds that the top metal plate and the bottom metal plate are provided with the same periodic grooves, and the coupling capacitance is generated between the upper groove and the lower groove, so that the electrical property parameters of the dielectric substrate can be influenced, the propagation constant and the impedance characteristic of the dielectric layer are changed, the propagation of electromagnetic waves is further influenced, and the slow wave characteristic is formed. The two slow wave structures formed by the slots enable electromagnetic waves to be converted from spherical waves into plane waves at the radiation port of the horn antenna, the width of a radiation lobe is reduced, and the radiation efficiency of the antenna is effectively improved. Compared with the traditional horn antenna, the invention has the advantages of good directivity, wider frequency band, higher gain, greatly improved radiation efficiency, low section, small size, lower connection loss with a planar circuit, easier integration realization, simple structure, easy processing and lower engineering application cost.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a bottom view of the structure of FIG. 1;

FIG. 3 is a top view of the structure of FIG. 1;

FIG. 4 is a side view structural diagram of FIG. 1;

FIG. 5 is a perspective structural view of FIG. 2;

FIG. 6 is a schematic diagram of a miniaturized broadband SW-SIW horn antenna S of the present invention₁₁The HFSS simulation result graph of (1);

FIG. 7 is a H-plane radiation pattern of a miniaturized broadband SW-SIW horn antenna of the present invention;

FIG. 8 is a diagram of the electric field distribution of the miniaturized broadband SW-SIW horn antenna of the present invention.

Detailed Description

Example (b): a miniaturized broadband SW-SIW horn antenna, as shown in fig. 1-4, includes a dielectric layer 2, a top metal layer 1 is disposed on the top surface of the dielectric layer 2, a bottom metal layer 4 is disposed on the bottom surface of the dielectric layer 2, a microstrip line structure 8 and a transition structure 9 for transforming SIW into microstrip are disposed at the front end of the top metal layer 1; grooves with corresponding positions and shapes are formed in the middle positions of the top metal layer 1 and the bottom metal layer 4 to form a slow-wave structure A6 and a slow-wave structure B7, and the grooves forming the slow-wave structure A6 and the slow-wave structure B7 are symmetrical along the central axis of the dielectric layer 2 and are periodically distributed; the dielectric layer 2 is provided with a front-end metal cylinder 10 and a guide metal cylinder which are symmetrical along a central axis, and the front-end metal cylinder 10 and the guide metal cylinder both penetrate through the dielectric layer 2 and are connected with the top metal layer 1 and the bottom metal layer 4, so that the top metal layer 1 and the bottom metal layer 4 are electrically connected; the front end metal cylinders 10 are arranged in parallel at two sides of the front end of the dielectric layer 2 and form equivalent rectangular waveguides, and the guide metal cylinders are positioned at the tail ends of the front end metal cylinders 10 and distributed in a step shape along the opening angles of the two side edges of the dielectric layer 2. In this embodiment, the structure of the guiding metal cylinder is as shown in fig. 5, and is divided into 8 groups, which are respectively marked with 11-18 in the drawing, and the grouping design conforms to a certain opening angle and is distributed in a ladder shape, so as to realize better impedance matching of the antenna, keep better directivity of the horn antenna, improve the gain of the antenna, further improve the radiation efficiency of the antenna, and further improve the performance of the antenna. But is not limited to such a scheme.

In the front-end metal cylinder 10 and the guide metal cylinder, the distance p between adjacent metal cylinders meets lambda_c/4>p>λ_c/20 diameter of metal cylinder d₁Satisfy d₁<p<2.5d₁Wherein λ is_cIs the cutoff wavelength for the main mode transmission of SIW.

The ends of the top metal layer 1 and the bottom metal layer 4 are both provided with rectangular arrays 5, and the upper and lower groups of rectangular arrays 5 are vertically symmetrical and form a dipole array 19 together.

In this embodiment, the dielectric substrate 2 is a Rogers Ro6002 dielectric substrate material, and has a relative dielectric constant of 2.94 and a loss tangent of 0.0012. The method has the characteristics of low dielectric loss, good cut-off adhesion of the conduction band metal and the substrate and the like.

In this embodiment, the grooves forming the slow-wave structures A6 and B7 may be regular or irregular, and the overall shape finally formed by the periodic arrangement may be adjusted according to actual parameter requirements.

The ANSOFT HFSS simulation results of this example are shown in fig. 6. Return loss curve S from horn antenna₁₁It can be seen that the passband width of the horn antenna is 32.87 GHz-35.08 GHz, and the communication bandwidth is 2.21 GHz. Fig. 7 shows that the SW-SIW horn antenna of the present invention has better directivity, better suppression of side lobes, and a gain of 12.1dB in the maximum radiation direction. As shown in FIG. 8, the SW-SIW horn antenna of the present invention has the electromagnetic wave propagating in the radiation portThe spherical wave forms plane wave, reduces the width of radiation lobe and improves the radiation efficiency of the antenna.

Claims

1. A miniaturized broadband SW-SIW horn antenna comprises a dielectric layer (2) and is characterized in that a top metal layer (1) is arranged on the top surface of the dielectric layer (2), a bottom metal layer (4) is arranged on the bottom surface of the dielectric layer (2), and a microstrip line structure (8) and a transition structure (9) for converting SIW into microstrip are arranged at the front end of the top metal layer (1); grooves with corresponding positions and shapes are formed in the middle positions of the top metal layer (1) and the bottom metal layer (4) to form a slow-wave structure A (6) and a slow-wave structure B (7), and the grooves forming the slow-wave structure A (6) and the slow-wave structure B (7) are symmetrical along the central axis of the dielectric layer (2) and are distributed periodically; the medium layer (2) is provided with a front-end metal cylinder (10) and a guide metal cylinder which are symmetrical along the central axis, and the front-end metal cylinder (10) and the guide metal cylinder both penetrate through the medium layer (2) and are connected with the top metal layer (1) and the bottom metal layer (4) to form electrical connection between the top metal layer (1) and the bottom metal layer (4); the front-end metal cylinders (10) are arranged in parallel at two sides of the front end of the dielectric layer (2) and form equivalent rectangular waveguides, and the guide metal cylinders are positioned at the tail ends of the front-end metal cylinders (10) and distributed in a step shape along the opening angles of the edges of the two sides of the dielectric layer (2); the tail end of the front end metal cylinder (10) is sequentially provided with a second metal column (11), a third metal column (12), a fourth metal column (13), a fifth metal column (14), a sixth metal column (15), a seventh metal column (16), an eighth metal column (17) and a ninth metal column (18) which are distributed in a stepped and symmetrical manner.

2. The miniaturized broadband SW-SIW feedhorn of claim 1, wherein said front metal cylinder (10) and said guiding metal cylinder are spaced apart from each other by a distance between adjacent ones of said guiding metal cylinderspSatisfy the requirement ofλ _c/4>p>λ _c/20 diameter of metal cylinderd ₁Satisfy the requirement ofd ₁<p<2.5d ₁Wherein, in the step (A),λ _cis the cutoff wavelength for the main mode transmission of SIW.

3. The miniaturized broadband SW-SIW feedhorn of claim 1, wherein rectangular arrays (5) are disposed at the ends of the top metal layer (1) and the bottom metal layer (4), and the two sets of rectangular arrays (5) are vertically symmetric and form a dipole array (19) together.