CN109546348B - A novel miniaturized broadband SW-SIW horn antenna and its design method - Google Patents

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

A novel miniaturized broadband SW-SIW horn antenna and its design method

technical field

The invention belongs to the technical field of microwave antenna engineering, and can be widely used in interstellar communication, 5G (5th-generation) communication and millimeter wave communication, especially a miniaturized broadband slow-wave substrate integrated waveguide (SW-SIW, SlowWave-Substrate Integrated Waveguide) technology H-plane horn antenna.

Background technique

With the arrival of a new generation of wireless communication technology, the entire international community is stepping up efforts to build a new generation of communication infrastructure and research and develop a new generation of communication technology and new microwave devices. The new generation of communication systems also puts forward higher requirements for the performance and integration of microwave devices. The antenna is the most critical component of the communication system, and has a wide range of applications in daily life, aerospace, interstellar communication and other fields. It is very important to realize broadband communication and miniaturization of the antenna.

Compared with the traditional microstrip antenna, the horn antenna has a simpler structure and a convenient feeding method. Moreover, the horn antenna can realize high-frequency communication, and has the advantages of wide frequency band, strong directivity, and high gain. However, compared with the traditional microstrip antenna, the horn antenna is relatively large in size, occupies a large space and is difficult to integrate. Moreover, the horn antenna is connected to the circuit system by the traditional coaxial transition method, which often produces a large amount of noise. insertion loss.

Substrate Integrated Waveguide (SIW, Substrate Integrated Waveguide) technology, SIW and traditional rectangular metal waveguide have a similar quasi-closed planar waveguide structure, with good transmission characteristics. Moreover, the substrate-integrated waveguide is processed by standard PCB technology, and has the characteristics of high Q value, easy processing and integration, light weight and small size. The substrate-integrated waveguide is also a waveguide structure. The cut-off frequency of the waveguide is mainly determined by the bandwidth. Compared with the coplanar waveguide and the microstrip circuit, the physical size of the SIW is still very large. The slow wave (SW, Slow Wave) structure was first used in the traveling wave tube, which can reduce the speed of the electromagnetic wave propagating in the slow wave structure, and the wavelength of the corresponding electromagnetic wave will also become smaller. Since the size of the antenna is also related to the wavelength of the electromagnetic wave, the SW structure can further reduce the physical size of the antenna. Therefore, the miniaturized broadband SW-SIW horn antenna has long-term scientific significance and practical application value in the application of wireless communication.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a new type of miniaturized broadband SW-SIW horn antenna, which has wider frequency band, higher gain, good directivity, greatly improves radiation efficiency, reduces volume, and is easier to implement Integrated, simple structure, low application cost.

The present invention is realized as follows: a miniaturized broadband SW-SIW horn antenna includes a dielectric layer, a top metal layer is provided on the top surface of the dielectric layer, a bottom metal layer is provided on the bottom surface of the dielectric layer, and a front end of the top metal layer is provided There are microstrip line structure and transition structure of SIW to microstrip; grooves with corresponding positions and shapes are opened in the middle of the top metal layer and the bottom metal layer to form slow wave structure A and slow wave structure B, forming slow wave The grooves of structure A and slow-wave structure B are symmetrical along the central axis of the dielectric layer and are periodically distributed; on the dielectric layer there are front-end metal cylinders and guide metal cylinders that are symmetrical along the central axis, and both the front-end metal cylinder and the guide metal cylinder are It penetrates through the dielectric layer and is connected to the top metal layer and the bottom metal layer, so that the top metal layer and the bottom metal layer are electrically connected; the front metal cylinder is arranged in parallel on both sides of the front end of the dielectric layer, and forms an equivalent rectangular waveguide, which guides the metal cylinder It is located at the end of the metal cylinder at the front end, and the opening angles along the edges of both sides of the dielectric layer are distributed in a stepped shape. The guiding metal cylinder is mainly to achieve better impedance matching of the antenna, keep the horn antenna in good directivity, improve the gain and radiation efficiency of the antenna, and further improve the performance of the antenna.

In the front-end metal cylinder and the guide metal cylinder, the spacing p between adjacent metal cylinders satisfies λ _c /4>p>λ _c /20, and the diameter d ₁ of the metal cylinder satisfies d ₁ <p<2.5d ₁ , where λ _c is the cutoff wavelength of the dominant mode transmission of SIW.

Rectangular arrays are arranged at the ends of the top metal layer and the bottom metal layer, and the upper and lower two sets of rectangular arrays are symmetrical up and down, and together form a dipole array. By loading the dipole array, the gain of the antenna is increased, the radiation energy is more concentrated, the directivity of the antenna is improved, and the radiation efficiency and performance of the antenna are further improved.

Due to the adoption of the above technical solution, the inventors of the present invention found that the same periodic grooves are formed on the top metal plate and the bottom metal plate, and coupling capacitances are generated between the upper and lower grooves, which will affect the electrical performance parameters of the dielectric substrate and make the dielectric layer The propagation constant and impedance characteristics of the electromagnetic wave are changed, which in turn affects the propagation of electromagnetic waves and forms slow-wave characteristics. The two slow-wave structures formed by the slot make the electromagnetic wave change from spherical wave to plane wave at the radiation port of the horn antenna, which reduces the width of the radiation lobe and effectively improves the radiation efficiency of the antenna. Compared with the traditional horn antenna, the present invention has good directivity, wider frequency band, and higher gain, greatly improves the radiation efficiency, has a low profile, small size, low connection loss with a plane circuit, and is easier to integrate. It has the advantages of simple structure, easy processing and low engineering application cost.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Fig. 2 is the bottom view structure diagram of Fig. 1;

Fig. 3 is the top view structure diagram of Fig. 1;

Fig. 4 is the side view structure diagram of Fig. 1;

Fig. 5 is the perspective structure diagram of Fig. 2;

Fig. 6 is the HFSS simulation result diagram of the miniaturized broadband SW-SIW horn antenna _S11 of the present invention;

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

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

Detailed ways

Example: A miniaturized broadband SW-SIW horn antenna, as shown in Figures 1-4, includes a dielectric layer 2, a top metal layer 1 is provided on the top surface of the dielectric layer 2, and a bottom metal layer is provided on the bottom surface of the dielectric layer 2 4. The front end of the top metal layer 1 is provided with a microstrip line structure 8 and an SIW-to-microstrip transition structure 9; the middle positions of the top metal layer 1 and the bottom metal layer 4 are provided with slots corresponding to positions and shapes, The slow-wave structure A 6 and the slow-wave structure B 7 are formed, 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 periodically distributed; The front-end metal cylinder 10 and the guide metal cylinder are symmetrical with the central axis. The front-end metal cylinder 10 and the guide metal cylinder 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 connected. The electrical connection is formed; the front metal cylinder 10 is arranged in parallel on both sides of the front end of the dielectric layer 2 to form an equivalent rectangular waveguide. distributed. In this embodiment, the structure of the guide metal cylinder is shown in Fig. 5, which is divided into 8 groups, which are labeled 11-18 in the drawing. Good impedance matching can keep the horn antenna in good directivity, improve the gain of the antenna, and then improve the radiation efficiency of the antenna, so that the performance of the antenna is further improved. But it is not limited to such a scheme.

In the front-end metal cylinder 10 and the guide metal cylinder, the spacing p between adjacent metal cylinders satisfies λ _c /4>p>λ _c /20, and the diameter d ₁ of the metal cylinder satisfies d ₁ <p<2.5d ₁ , where λ _c is the cutoff wavelength of the dominant mode transmission of SIW.

Rectangular arrays 5 are provided at the ends of the top metal layer 1 and the bottom metal layer 4 , and the upper and lower two sets of rectangular arrays 5 are symmetrical and form a dipole array 19 together.

In this embodiment, the material of the dielectric substrate 2 is Rogers Ro6002 dielectric substrate material, the relative permittivity is 2.94, and the loss tangent is 0.0012. It has the characteristics of low dielectric loss and good cut-off adhesion between conduction band metal and substrate.

In this embodiment, the grooves forming the slow-wave structure A 6 and the slow-wave structure B 7 may be of regular shape or irregular shape, and the final overall shape formed according to the periodic arrangement can also be adjusted according to actual parameters. of.

The ANSOFT HFSS simulation result of this embodiment is shown in FIG. 6 . It can be seen from the return loss curve _S11 of the horn antenna that the passband width of the invented horn antenna is 32.87GHz-35.08GHz, and the communication bandwidth is 2.21GHz. As shown in FIG. 7 , the SW-SIW horn antenna of the present invention has good directivity, the side lobes are well suppressed, and the gain in the maximum radiation direction is 12.1 dB. As shown in FIG. 8 , in the SW-SIW horn antenna of the present invention, the propagating electromagnetic wave forms a plane wave from a spherical wave at the radiation port, which reduces the radiation lobe width and improves the radiation efficiency of the antenna.

Claims (3)

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 ₁ Satisfy the requirement ofd ₁ <p<2.5d ₁ Wherein, in the step (A),λ _c is 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.

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