CN117060086A - Open cavity miniaturized broadband antenna based on substrate integrated waveguide - Google Patents

Abstract

The invention is an open cavity miniaturized broadband antenna based on a substrate integrated waveguide, belonging to the field of microwave antennas. It discloses a secondary open cavity substrate integrated wave miniaturized broadband antenna, which includes a bottom dielectric substrate and an upper dielectric substrate. A first metal layer is provided on the lower surface of the underlying dielectric substrate, and a second metal layer is provided on the upper surface of the underlying dielectric substrate. The second metal layer has a cracked strip-shaped open circuit gap, which is the first metal layer and the second metal layer. layer and the radiation surface of the underlying dielectric substrate. Several metal cylinders penetrate the underlying dielectric substrate, and the upper and lower ends of the several metal cylinders are connected to the first metal layer and the second metal layer respectively. The second metal layer is far away from the strip-shaped open circuit gap. One side is connected to the microstrip line feed, and the upper dielectric substrate is attached to the upper surface of the second metal layer and attached to the strip-shaped open circuit gap where the second metal layer is cracked. The miniaturized broadband antenna of the present invention covers the X frequency band, and increases the impedance bandwidth under the influence of the number and position of loading open gaps and metal through holes.

Description

An open cavity miniaturized broadband antenna based on substrate integrated waveguide

Technical field

The invention belongs to the field of microwave antennas, and specifically relates to an open-cavity miniaturized broadband antenna based on a substrate integrated waveguide.

Background technique

The antenna is a wireless communication device used to send and receive radio signals. Its performance determines the quality of the entire communication system to a certain extent. With the development of communication systems today, our demand for antenna miniaturization and broadband is gradually increasing. Traditional antennas usually face problems such as large size, narrow bandwidth, and low efficiency. Miniaturized antennas can meet more device integration requirements, but they face the problem of a narrow frequency range and cannot meet broadband applications. Therefore, how to design and produce miniaturized broadband antennas has become an important research topic in the field of antenna science and technology.

Substrate integrated waveguide antennas are significantly superior to traditional microstrip antennas and waveguide antennas due to their compact structure, efficient performance, and ease of manufacturing. However, due to its high Q value, the frequency band bandwidth is narrow. Under certain conditions, the Q value of an electrically small antenna is inversely proportional to the bandwidth. Therefore, the bandwidth of the antenna can be improved by partially opening the closed cavity to reduce the energy storage in the SIW cavity and reduce the Q value of the antenna.

In the past, there were a lot of research on miniaturized broadband antennas based on substrate integrated waveguides, but there were not many designs that took into account both operating bandwidth and gain. Therefore, it is of great significance to develop antennas with good operating bandwidth and gain performance.

Contents of the invention

In order to solve the above technical problems, the present invention provides an open-cavity miniaturized broadband antenna based on a substrate integrated waveguide, and realizes a new idea of miniaturizing the open-cavity broadband antenna with an open SIW back-cavity slot antenna. By removing some metal pillars, the narrow-band antenna can be The antenna is converted into a broadband antenna with simple design and structure and obvious effect.

In order to achieve the above objects, the present invention is achieved through the following technical solutions:

The invention is an open-cavity miniaturized broadband antenna based on a substrate integrated waveguide. The open-cavity miniaturized broadband antenna covers the X-band and includes a bottom dielectric substrate and an upper dielectric substrate. A first metal is provided on the lower surface of the bottom dielectric substrate. layer, a second metal layer is provided on the upper surface of the underlying dielectric substrate. The second metal layer has a cracked strip-shaped open circuit gap, which is the radiation surface of the first metal layer, the second metal layer and the underlying dielectric substrate, and several The metal cylinder penetrates the underlying dielectric substrate and the upper and lower ends of several metal cylinders are connected to the first metal layer and the second metal layer respectively, forming a SIW resonant cavity, which is connected on the side of the second metal layer away from the strip-shaped open circuit gap. The microstrip line feeds to form a co-excitation waveguide feed structure. The upper dielectric substrate is attached to the upper surface of the second metal layer and attached to the strip-shaped open circuit gap where the second metal layer is cracked. On the upper surface of the upper dielectric substrate is The third metal layer.

A further improvement of the present invention is that the third metal layer is a T-shaped metal patch with two gap widths, four metal short-circuit via holes are provided on the upper dielectric substrate, and the four metal short-circuit via holes penetrate the upper dielectric substrate. The size of the upper dielectric substrate is 1/4.5 of the size of the bottom dielectric substrate.

A further improvement of the present invention is that the width of the strip opening gap and the gap are consistent, both being 1.55mm-1.75mm.

A further improvement of the present invention is that: the bottom dielectric substrate on the same side as the microstrip line feed is opened, that is, no metal cylinder is provided, and the strip open circuit gap is opened on the bottom dielectric substrate on the same side as the microstrip line feed. In the process, no metal cylinder is provided, and three metal cylinders are provided on both sides of the underlying dielectric substrate on the different side from the microstrip line feed, with the center of the strip-shaped open-circuit gap as the symmetry axis.

A further improvement of the present invention is that the impedances of the microstrip line feed and the port are both 50 ohms.

The working principle of the present invention is: several metal cylinders penetrate the middle layer dielectric substrate, and the two ends are connected to the first metal layer and the second metal layer respectively, forming a SIW resonant cavity, thereby achieving the purpose of a low profile antenna; The resonant cavity is fed through the coplanar waveguide structure of the second metal layer, which excites the open-circuit gap of the second metal layer to radiate electromagnetic waves outward, and is coupled to the second layer of dielectric substrate through the gap and four metal short-circuit via holes. Surface, optimize the shape and position of the patch in the third metal layer to construct a secondary open miniaturized broadband antenna. The entire antenna has good radiation performance, low cross-polarization levels on the E and H surfaces, a flat gain curve within the operating frequency range, the maximum gain reaches 7.14dBi, and the relative bandwidth within the operating frequency range reaches 25.86%; Compared with other types of SIW broadband antennas, the present invention exhibits good performance in terms of relative operating bandwidth and radiation gain within the operating frequency range.

The beneficial effects of the present invention are:

(1) The present invention reduces the Q value of the SIW cavity by removing part of the metal pillars, increases the energy radiation of the side wall, and broadens the antenna bandwidth under the action of loading the open-circuit gap.

(2) By introducing a second layer of completely open antenna structure, the present invention enables the antenna to have a lower cross-polarization level in the process of expanding the bandwidth.

(3) The present invention proposes a new design to realize an open SIW miniaturized broadband antenna, and due to the independence of the parasitic patch, the antenna is simpler than other SIW array broadband antennas without adding additional complexity. Under the conditions of matching network and special structure, only part of the metal pillars need to be removed to increase the impedance bandwidth.

(4) The present invention finally enables the open SIW miniaturized broadband antenna to maintain good radiation performance while making the antenna structure simpler and easier to process.

Description of the drawings

Figure 1 is a schematic perspective view of the present invention.

Figure 2 is a partial top view of the present invention.

Figure 3 is a partial top view of the present invention.

Figure 4 is a simulated S-parameter diagram according to the embodiment of the present invention.

Figure 5 is a simulation gain diagram according to the embodiment of the present invention.

Figure 6 is the main polarization and cross-polarization E-plane simulation pattern at 9.7GHz according to the embodiment of the present invention.

Figure 7 is the main polarization and cross-polarization H-plane simulation pattern at 9.7GHz according to the embodiment of the present invention.

Figure 8 is a simulation pattern of the main polarization and cross-polarization E-plane at 10.6 GHz according to the embodiment of the present invention.

Figure 9 is the main polarization and cross-polarization H-plane simulation pattern at 10.6GHz according to the embodiment of the present invention.

Figure 10 is the main polarization and cross-polarization E-plane simulation pattern at 11.75GHz according to the embodiment of the present invention.

Figure 11 is the main polarization and cross-polarization H-plane simulation pattern at 11.75GHz according to the embodiment of the present invention.

Among them: 1-first metal layer, 2-second metal layer, 3-third metal layer, 4-bottom dielectric substrate, 6-upper dielectric substrate, 7-microstrip line feed, 8-slit, 9-T Type metal patch, 10-metal short-circuit through hole, 11-strip open-circuit gap.

Detailed ways

The following will disclose the embodiments of the present invention in the drawings. For the sake of clarity, many practical details will be explained in the following description. However, it will be understood that these practical details should not limit the invention. That is to say, in some embodiments of the invention, these practical details are not necessary. In addition, in order to simplify the drawings, some commonly used structures and components will be shown in the drawings in a simple schematic manner.

The present invention provides an open type SIW miniaturized broadband antenna. By removing some metal pillars on the side wall, the energy storage in the SIW cavity is reduced, the Q value of the antenna is reduced, and the bandwidth is broadened; and through gaps and short-circuit through holes, the energy storage in the SIW cavity is reduced. Coupling introduces a second layer of substrate structure to reduce the cross-polarization of the antenna and further improve the bandwidth.

As shown in Figures 1-3, the present invention is an open-cavity miniaturized broadband antenna based on a substrate integrated waveguide. The open-cavity miniaturized broadband antenna covers the X-band. The open-cavity miniaturized broadband antenna of the invention includes an underlying dielectric substrate. 4 and an upper dielectric substrate 6. The size of the upper dielectric substrate 6 is 1/4.5 of the size of the bottom dielectric substrate 4. A first metal layer 1 is provided on the lower surface of the bottom dielectric substrate 4. The upper surface of the dielectric substrate 4 is provided with a second metal layer 2. The second metal layer 2 has a split strip-shaped open circuit gap 11, which is the connection between the first metal layer 1, the second metal layer 2 and the underlying dielectric substrate 4. On the radiation surface, several metal cylinders penetrate the underlying dielectric substrate 4 and the upper and lower ends of the several metal cylinders are connected to the first metal layer 1 and the second metal layer 2 respectively, forming a SIW resonant cavity. In the second The side of the metal layer 2 away from the strip-shaped open-circuit gap 11 is connected to the microstrip line feed 7 to form a co-excitation waveguide feed structure. The impedances of the microstrip line feed 7 and the port are both 50 ohms, and the upper dielectric substrate 6 is attached On the upper surface of the second metal layer 2 and attached to the strip-shaped open slit 11 of the second metal layer 2, on the upper surface of the upper dielectric substrate 6 is the third metal layer 3, and the strip The width of the shaped open-circuit gap 11 is consistent with that of the gap 8, and both are 1.55mm-1.75mm, preferably: 1.65mm. The open-circuit gap couples energy from the bottom layer to the upper layer, reducing the energy leakage of the open cavity of the bottom layer. The third The metal layer 3 is a T-shaped metal patch 9 with two gaps 8 spaced apart. Four metal short-circuit vias 10 are provided on the upper dielectric substrate 6 and the four metal short-circuit vias 10 penetrate the upper layer. The dielectric substrate 6, the bottom dielectric substrate 4 on the same side as the microstrip line feed 7 is open, that is, no metal cylinder is provided, and the bottom dielectric substrate 4 on the same side as the microstrip line feed 7 Above, the strip-shaped open-circuit gap 11 is open, that is, no metal cylinder is provided. On the underlying dielectric substrate 4 on a different side from the microstrip line feed 7, the center of the strip-shaped open-circuit gap 11 is There are three metal cylinders on both sides of the symmetry axis.

The open SIW miniaturized broadband antenna of the present invention is an open structure improved by a closed substrate integrated waveguide cavity. It achieves a combination of miniaturization and broadband without adding complex network feeds and design structures, and is easier to integrate with planar circuits and has better practicability.

The technical solution of the present invention is further elaborated below through specific examples:

In this embodiment, as shown in Figure 1, the open SIW miniaturized broadband antenna consists of two layers of dielectric substrates, both of which use Rogers5880. The dielectric constant is 2.2, the loss tangent is 0.0009, and the thicknesses are 1.575mm and 0.787mm respectively. The bottom layer The upper surface of the dielectric board is covered with a third metal layer, the lower layer is covered with a lower second metal layer, and metal through holes are evenly distributed on the lower dielectric substrate. The metal cylinder penetrates the lower dielectric substrate through the metal through hole. There are two T-shaped metal patches on the upper surface of the upper dielectric board with a spacing of the width of the open circuit gap. The lower surface is attached to the surface of the upper metal layer of the bottom dielectric board, and 4 is added to the dielectric substrate. metal short-circuit vias. The original closed rectangular cavity SIW slot antenna S11≤-10dB has a frequency range of 10.74GHz-10.87GHz, a relative bandwidth of 1.2%, and a maximum gain of 3.26dBi in the operating frequency band. After opening, the frequency range of S11≤-10dB is 9.46GHz-12.27GHz, and three resonant frequency points are generated: 9.7GHz, 10.6GHz, and 11.75GHz. The impedance matching is good and the relative bandwidth reaches 25.86%. The gain curve in the operating frequency band is flat, with the maximum gain of 7.14dBi, reflecting good radiation characteristics.

As shown in Figure 2, it is the main first layer structure of the antenna structure of the present invention. It is fed by a 50Ω microstrip line. Several metal cylinders penetrate the intermediate dielectric substrate, and the two ends are connected to the first metal layer and the second metal layer respectively, forming a SIW resonant cavity. By etching the second metal layer For the strip-shaped open gap, remove some of the metal pillars around the strip-shaped open gap to open the closed cavity.

As shown in Figure 3, it is the second diagram of the main body of the antenna structure of the present invention, which consists of a dielectric substrate, two metal T-shaped patches on the upper surface, and four metal short-circuit through holes.

Figure 4 shows the simulation results of the S parameters of the open SIW miniaturized broadband antenna. The operating frequency range is 9.46GHz-12.27GHz, producing three resonant frequency points of 9.7GHz, 10.6GHz, and 11.75GHz. The impedance matching is good and the relative bandwidth reaches 25.86%.

Figure 5 shows the simulation gain results of the open SIW miniaturized broadband antenna.

Figure 6 is the main polarization and cross-polarization E-plane simulation direction diagram of the present invention at 9.7GHz.

Figure 7 is the main polarization and cross-polarization H-plane simulation direction diagram of the present invention at 9.7GHz.

Figure 8 is the main polarization and cross-polarization E-plane simulation direction diagram of the present invention at 10.6GHz.

Figure 9 is the main polarization and cross-polarization H-plane simulation direction diagram of the present invention at 10.6GHz.

Figure 10 is the main polarization and cross-polarization E-plane simulation pattern of the present invention at 11.75GHz.

Figure 11 is the main polarization and cross-polarization H-plane simulation pattern of the present invention at 11.75GHz.

It can be seen from Figures 6, 8 and 10 that the ratio of the main polarization to the cross-polarization on the E-plane of the antenna of the present invention is about 20dB. It can be seen from Figures 7, 9, and 11 that the ratio of the main polarization to the cross-polarization on the H plane of the antenna of the present invention is about 40dB.

The present invention finally realizes a miniaturized broadband antenna covering the X frequency band, with a relative bandwidth reaching 25.86%, a flat gain curve within the frequency band, a maximum gain reaching 7.14dBi, and good radiation performance. Starting from a simple open-cavity rectangular substrate integrated waveguide antenna, the bandwidth-broadening performance of the open-cavity substrate integrated waveguide antenna is verified. Without adding additional complex matching networks and special structures, only part of the metal pillars need to be removed. The impedance bandwidth is increased, the production is simple, and the cost is low, bringing more possibilities to the design of broadband antennas in the future.

The above descriptions are only embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations will occur to the present invention to those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims (8)

1. An open-cavity miniaturized broadband antenna based on a substrate integrated waveguide, including a bottom dielectric substrate (4) and an upper dielectric substrate (6). A first metal layer is provided on the lower surface of the bottom dielectric substrate (4). (1), a second metal layer (2) is provided on the upper surface of the underlying dielectric substrate (4), characterized in that: the second metal layer (2) has a split strip-shaped open circuit gap (11 ), is the radiation surface of the first metal layer (1), the second metal layer (2) and the underlying dielectric substrate (4). Several metal cylinders penetrate the underlying dielectric substrate (4) and the upper and lower sides of the several metal cylinders The ends are connected to the first metal layer (1) and the second metal layer (2) respectively, forming a SIW resonant cavity, which is connected on the side of the second metal layer (2) away from the strip-shaped open circuit gap (11). The microstrip line feeds (7) to form a coplanar waveguide feed structure. The upper dielectric substrate (6) is attached to the upper surface of the second metal layer (2) and is attached to the second metal layer (2). On the strip-shaped open slit (11), there is a third metal layer (3) on the upper surface of the upper dielectric substrate (6). 2. An open-cavity miniaturized broadband antenna based on a substrate integrated waveguide according to claim 1, characterized in that: the third metal layer (3) is a T-shape with two gaps (8) spaced apart. The metal patch (9) is provided with four metal short-circuit via holes (10) on the upper dielectric substrate (6), and the four metal short-circuit via holes (10) penetrate the upper dielectric substrate (6). 3. An open-cavity miniaturized broadband antenna based on a substrate integrated waveguide according to claim 2, characterized in that the width of the strip-shaped open-circuit slot (11) is consistent with that of the slot (8). 4. An open-cavity miniaturized broadband antenna based on a substrate integrated waveguide according to claim 3, characterized in that: the widths of the strip-shaped open-circuit slot (11) and the slot (8) are both 1.55mm. -1.75mm. 5. An open-cavity miniaturized broadband antenna based on a substrate integrated waveguide according to claim 1, characterized in that: the underlying dielectric substrate (4) is on the same side as the microstrip line feed (7) On the same side as the microstrip line feed (7), the bottom dielectric substrate (4) and the strip-shaped open circuit gap (11) are open, that is, no metal cylinder is provided. Metal cylinders, three metal cylinders are respectively provided on both sides of the underlying dielectric substrate (4) on the different side from the microstrip line feed (7), with the center of the strip-shaped open-circuit gap (11) as the symmetry axis. . 6. An open-cavity miniaturized broadband antenna based on a substrate integrated waveguide according to claim 1, characterized in that: the size of the upper dielectric substrate (6) is 1 times the size of the bottom dielectric substrate (4). /4.5. 7. An open-cavity miniaturized broadband antenna based on a substrate integrated waveguide according to claim 1, characterized in that: the impedances of the microstrip line feed (7) and the port are both 50 ohms. 8. An open-cavity miniaturized broadband antenna based on a substrate integrated waveguide according to any one of claims 1-7, characterized in that: the open-cavity miniaturized broadband antenna covers the X-band.