Open-type compact wideband antenna based on substrate-integrated waveguide

Abstract

The present invention relates to a compact, wideband antenna based on a secondary open-circuit integrated waveguide, which is related to the microwave antenna technology. It comprises a base dielectric substrate and an upper dielectric substrate. A first metal layer is provided on the lower surface of the base dielectric substrate, and a second metal layer is provided on the upper surface of the base dielectric substrate. The second metal layer has a split, strip-shaped open-circuit slit and functions as a radiating surface for the first metal layer, the second metal layer, and the base dielectric substrate. A plurality of metal cylinders penetrate the base dielectric substrate, and their upper and lower ends are connected to the first metal layer and the second metal layer, respectively. The second metal layer is connected to a microstrip line feed on the side away from the strip-shaped open-circuit slit. The upper dielectric substrate is attached to the upper surface of the second metal layer and also to the split, strip-shaped open-circuit slit in the second metal layer. The compact, wideband antenna of the present invention covers the X frequency band, and the impedance and bandwidth can be improved by optimizing the number and position of the open-circuit slits and metal through-holes.

Description

[Technical Field]

[0001] The present invention relates to the technical field of microwave antennas, and more particularly to an open-type compact wideband antenna based on a substrate-integrated waveguide (or an open-type compact wideband antenna using a substrate-integrated waveguide). [Background technology]

[0002] Antennas are wireless communication devices used to transmit and receive radio signals, and their performance affects the quality of the entire communication system. With the development of communication systems, there is an ever-increasing demand for smaller and broader antennas. Conventional antennas suffer from problems such as large size, narrow bandwidth, and low efficiency. While miniaturized antennas can meet more device integration requirements, they suffer from a narrow frequency range and are unable to be applied to broadband networks. Therefore, how to design and manufacture compact, broadband antennas has become an important research topic in the field of antenna technology.

[0003] Substrate-integrated waveguide antennas significantly outperform traditional microstrip and waveguide antennas due to their compact structure, efficient performance, and ease of fabrication. However, they have a narrow frequency bandwidth due to their high Q factor. Under certain conditions, the Q factor of an electrically small antenna is inversely proportional to its bandwidth. Therefore, the antenna bandwidth can be improved by partially opening the closed cavity to reduce energy accumulation in the SIW cavity and lower the antenna Q factor.

[0004] Although there have been many studies on compact broadband antennas using substrate-integrated waveguides, there have been no designs that take into account both the operating bandwidth and gain. Therefore, the development of antennas with good operating bandwidth and gain performance is very important. Summary of the Invention [Problem to be solved by the invention]

[0005] To solve the above technical problems, the present invention provides an open-type small-sized wideband antenna based on a substrate-integrated waveguide, which realizes a wideband antenna with a slit structure in an open-type SIW and eliminates some metal pillars, thereby improving the narrowband antenna into a wideband antenna structure with a simple design and structure and improving performance effects. [Means for solving the problem]

[0006] To achieve the above objectives, the present invention proposes the following technical solutions:

[0007] The present invention provides an open-type small wideband antenna using a substrate-integrated waveguide, the open-type small wideband antenna covering the X-band, comprising a base dielectric substrate and an upper dielectric substrate. A first metal layer is provided on the lower surface of the base dielectric substrate, and a second metal layer is provided on the upper surface of the base dielectric substrate, the second metal layer having a cleaved strip-shaped open-circuit slit (slit structure) that functions as a radiation surface for the first metal layer, the second metal layer, and the base dielectric substrate. A plurality of metal cylinders penetrate the base dielectric substrate, and the upper and lower ends of the plurality of metal cylinders are connected to the first metal layer and the second metal layer, respectively. No metal column is provided near the slit (11) of the open circuit, thereby forming a partially open SIW structure. The second metal layer is connected to the microstrip line feed on the side of the strip-shaped open circuit away from the slit, thereby forming SIW A power supply structure is formed by attaching an upper dielectric substrate to the upper surface of the second metal layer and to the slits of the open circuit of the split strip-shaped second metal layer. The upper surface of the upper dielectric substrate is a third metal layer.

[0008] Further improvements of the present invention are as follows: the third metal layer is composed of two T-shaped metal patches spaced apart by the width of the slit, the upper dielectric substrate is provided with four metal shorting through holes, and the four metal shorting through holes penetrate the upper dielectric substrate, and the size of the upper dielectric substrate is 1 / 4.5 of the size of the underlying dielectric substrate.

[0009] Further improvements of the present invention are as follows: The width of the slit of the strip-shaped open circuit is the same as the width of the slit, both of which are 1.55 mm to 1.75 mm.

[0010] Further improvements of the present invention are as follows: the underlayer dielectric substrate on the same side as the microstrip line feed is opened so as to have no metal cylinders to form an open structure, the underlayer dielectric substrate on the same side as the microstrip line feed is opened so as to have no metal cylinders at the slits of the strip-shaped open circuit to form an open structure, and the underlayer dielectric substrate on the opposite side from the microstrip line feed is provided with three metal cylinders on each side of the symmetry axis at the center of the slit of the strip-shaped open circuit (a straight line that runs perpendicular to the longitudinal direction of the slit and passes through the longitudinal center of the slit).

[0011] Further improvements of the present invention are as follows: Further improvements of the present invention are as follows: The impedance of the microstrip line feed and end ports is 50 ohms.

[0012] The working principle of the present invention is as follows: A plurality of metal cylinders penetrate the dielectric substrate of the intermediate layer; SIW power supply structure The two ends are connected to the first metal layer and the second metal layer, respectively, to form a low profile. A wideband SIW power supply structure is formed by eliminating the metal pillar for SIW waveguiding near the open circuit slit and opening the SIW structure. Second metal layer SIW structure using microstrip line structureWhen power is supplied to the antenna, the open-circuit slit in the second metal layer is excited, radiating electromagnetic waves to the outside. Furthermore, the slit and four metal short-circuit through-holes are electrically coupled to the upper surface of the second dielectric substrate. By optimizing the shape and position of the patch in the third metal layer, a two-dimensional open-circuit compact wideband antenna can be formed. The antenna has good radiation performance, relatively low cross-polarization levels in the E-plane and H-plane, a flat gain curve within the operating frequency range, a maximum gain of 7.14 dBi, and a relative bandwidth of 25.86% within the operating frequency range. Compared with other types of SIW wideband antennas, the present invention exhibits good performance in terms of relative operating bandwidth and radiation gain within the operating frequency range. [Effects of the Invention]

[0013] The advantageous effects of the present invention are as follows:

[0014] (1) By removing some of the metal pillars, the present invention can reduce the Q value of the SIW cavity and increase the energy radiation from the sidewalls. Also, by providing an open-circuit slit, the antenna bandwidth can be broadened.

[0015] (2) By introducing a second layer of a completely open (open, aperture-type) antenna structure, the present invention can relatively reduce the cross-polarization level of the antenna while broadening the antenna bandwidth.

[0016] (3) This invention proposes a new design for realizing an open-type SIW compact broadband antenna. Due to the independence of the parasitic patch, the antenna of this invention has a simpler structure than other SIW and other array broadband antennas. The impedance bandwidth can be increased by simply removing some metal pillars without adding complex network matching or special structures.

[0017] (4) The present invention finally enables an open-type SIW miniature broadband antenna to have a simpler and easier to fabricate antenna structure while maintaining good radiation performance. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view of the present invention. [Figure 2] FIG. 1 is a plan view of the present invention. [Figure 3] FIG. 2 is a plan view of a localized portion of the present invention. [Figure 4] FIG. 10 is a diagram showing a simulation result of S parameters in the embodiment of the present invention. [Figure 5] FIG. 10 is a diagram illustrating a simulation result of a gain in an embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing simulation results of main polarization and cross polarization E-plane antenna patterns of an embodiment of the present invention at 9.7 GHz. [Figure 7] 10A and 10B are diagrams showing simulation results of main polarization and cross polarization H-plane antenna patterns of an embodiment of the present invention at 9.7 GHz. [Figure 8] FIG. 10 is a diagram showing simulation results of main polarization and cross polarization E-plane antenna patterns of an embodiment of the present invention at 10.6 GHz. [Figure 9] FIG. 10 is a diagram showing simulation results of main polarization and cross polarization H-plane antenna patterns of an embodiment of the present invention at 10.6 GHz. [Figure 10] FIG. 10 is a diagram showing simulation results of main polarization and cross polarization E-plane antenna patterns of an embodiment of the present invention at 11.75 GHz. [Figure 11] FIG. 10 is a diagram showing simulation results of main polarization and cross polarization H-plane antenna patterns of an embodiment of the present invention at 11.75 GHz. [Explanation of symbols]

[0019] 1: First metal layer, 2: Second metal layer, 3: Third metal layer, 4: Underlayer dielectric substrate, 6: Upper layer dielectric substrate, 7: Microstrip line feed, 8: Slit, 9: T-shaped metal patch, 10: Metal short-circuit through-hole, 11: Strip-shaped open circuit slit DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For clarity, the following description will explain details for implementing the invention. However, it should be understood that these details do not limit the present invention. That is, the details described in some embodiments of the present invention are not essential configurations for the configuration of the present invention. Furthermore, to simplify the drawings, some commonly used structures and components are shown in schematic form.

[0021] This invention provides an open-type SIW (Substrate Integrated Waveguide) compact wideband antenna. By removing the metal pillars on the sidewalls, the energy accumulation in the SIW cavity is reduced, lowering the antenna's Q value and widening the bandwidth (making it possible to achieve broadband). In addition, by introducing a second-layer substrate structure through coupling with slits and short-circuit through-holes, the antenna's cross-polarization can be reduced, further improving and expanding the bandwidth.

[0022] 1 to 3 show an open-type small wideband antenna based on a substrate-integrated waveguide of the present invention. The open-type small wideband antenna covers the X-band. The open-type small wideband antenna of the present invention comprises a base layer dielectric substrate 4 and an upper layer dielectric substrate 6. The size of the upper layer dielectric substrate 6 is 1 / 4.5 of the size of the base layer dielectric substrate 4. A first metal layer 1 is provided on the lower surface of the base layer dielectric substrate 4. A second metal layer 2 is provided on the upper surface of the base layer dielectric substrate 4. The second metal layer 2 has open-circuit slits 11 in the shape of split strips (separated from each other), which function as radiation surfaces for the first metal layer 1, the second metal layer 2, and the base layer dielectric substrate 4. A plurality of metal cylinders penetrate the base layer dielectric substrate 4, and the upper and lower ends of the plurality of metal cylinders are connected to the first metal layer 1 and the second metal layer 2, The metal pillar for SIW waveguiding near the open circuit slit is not provided, and the circuit is partially open. SIW structure The second metal layer 2 is connected to the microstrip line feed 7 on the side of the strip-shaped open circuit away from the slit 11, Finally, broadband SIWA feed structure is formed. The impedance of the microstrip line feed 7 and the end port is both 50 ohms. An upper dielectric substrate 6 is attached to the upper surface of the second metal layer 2, and is attached over the split strip-shaped open-circuit slit 11 in the second metal layer 2. The upper surface of the upper dielectric substrate 6 is the third metal layer 3. The width of the strip-shaped open-circuit slit 11 matches the width of the slit 8, both being 1.55 mm to 1.75 mm, preferably 1.65 mm. The open-circuit slit couples energy from the base layer to the upper layer (energy is transmitted and reflected from the base layer to the upper layer), reducing energy leakage from the open-circuited base layer. The third metal layer 3 is composed of two T-shaped metal patches 9 spaced apart by the width of the slit 8. Four metal short-circuiting through holes 10 are provided in the upper layer dielectric substrate 6, and the four metal short-circuiting through holes 10 penetrate the upper layer dielectric substrate 6 and are open in the underlying layer dielectric substrate 4 on the same side as the microstrip line feed 7 (opening the conventional closed form, i.e., formed in a state where no metal cylinders are provided), and in the underlying layer dielectric substrate 4 on the same side as the microstrip line feed 7, the slit 11 of the strip-shaped open circuit is also open (i.e., formed in a state where no metal cylinders are provided), while on the other side of the underlying layer dielectric substrate 4 opposite to the microstrip line feed 7, three metal cylinders are provided on both sides with the center of the slit 11 of the strip-shaped open circuit as the symmetry axis (a line that passes through the longitudinal center of the slit 11 of the strip-shaped open circuit and is perpendicular to the longitudinal direction is the symmetry axis).

[0023] The open-type SIW compact broadband antenna of the present invention is an improved open-type structure based on a closed-substrate integrated waveguide cavity structure, which achieves both compactness and broadband performance without the need for complex network feeds or additional design structures, and is easy to integrate into planar circuits for practical use.

[0024] The technical solutions of the present invention are described below using specific embodiments.

[0025] As shown in Figure 1, the open-type SIW compact wideband antenna of this embodiment includes a two-layer dielectric substrate. The dielectric substrate is made of Rogers 5880, with a dielectric constant of 2.2, a loss tangent of 0.0009, and thicknesses of 1.575 mm and 0.787 mm, respectively. The top surface of the base dielectric substrate is covered with a third metal layer, and the bottom layer is covered with a second metal layer. Metal through-holes are evenly distributed in the base dielectric substrate. Metal cylinders penetrate the top dielectric substrate through the metal through-holes. The top surface of the top dielectric substrate is provided with two T-shaped metal patches spaced apart by the width of the open circuit slit. The bottom surface is the surface of the top metal layer of the base dielectric substrate, and the dielectric substrate is provided with four metal short-circuit through-holes. The closed-type rectangular cavity SIW slit antenna has a frequency range of 10.74 GHz to 10.87 GHz where S11 ≤ -10 dB, a relative bandwidth of 1.2%, and a maximum gain of 3.26 dBi within the operating frequency range. However, when converted to an open-type, the frequency range of 9.46 GHz to 12.27 GHz where S11 ≤ -10 dB can be achieved, generating three resonant frequency bins at 9.7 GHz, 10.6 GHz, and 11.75 GHz. The impedance matching is excellent, and the relative bandwidth reaches 25.86%. This results in a flat gain curve within the operating frequency range, a maximum gain of 7.14 dBi, and excellent radiation characteristics.

[0026] Figure 2 shows the first layer structure of the antenna structure body of the present invention. The structure is fed by a 50Ω microstrip line. A number of metal rods penetrate the middle layer dielectric substrate, and their ends are connected to the first and second metal layers, respectively, to form a SIW. Transmission Structure A closed cavity is formed by etching a strip-shaped open circuit slit in the second metal layer and removing some of the metal pillars around the strip-shaped open circuit slit. (SIW structure) partially Make it open.

[0027] Figure 3 shows the second diagram of the antenna structure body of the present invention, which is composed of a dielectric substrate, two metal T-patches arranged on the upper surface, and four metal short-circuiting through-holes (metal through-holes).

[0028] Figure 4 shows the S-parameter simulation results of the open-type SIW compact broadband antenna. The operating frequency range is 9.46 GHz to 12.27 GHz, with three resonant frequency bins at 9.7 GHz, 10.6 GHz, and 11.75 GHz. The impedance matching is good, and the relative bandwidth reaches 25.86%.

[0029] Figure 5 shows the simulation results of the gain of the open-type SIW compact wideband antenna.

[0030] FIG. 6 shows the simulation results of the main polarization and cross polarization E-plane antenna patterns of the present invention at 9.7 GHz.

[0031] FIG. 7 shows the simulation results of main polarization and cross polarization H-plane antenna patterns of the present invention at 9.7 GHz.

[0032] FIG. 8 shows the simulation results of the main polarization and cross polarization E-plane antenna patterns of the present invention at 10.6 GHz.

[0033] FIG. 9 is a diagram showing the simulation results of the main polarization and cross polarization H-plane antenna patterns of the present invention at 10.6 GHz.

[0034] FIG. 10 shows the simulation results of the main polarization and cross polarization E-plane antenna patterns of the present invention at 11.75 GHz.

[0035] FIG. 11 is a diagram showing the simulation results of main polarization and cross polarization H-plane antenna patterns of the present invention at 11.75 GHz.

[0036] As shown in Figures 6, 8, and 10, the antenna of the present invention has a ratio of main polarization to cross polarization in the E plane of about 20 dB. As shown in Figures 7, 9, and 11, the antenna of the present invention has a ratio of main polarization to cross polarization in the H plane of about 40 dB.

[0037] This invention ultimately provides a compact, wideband antenna covering the X frequency band (X-band), with a relative bandwidth of 25.86%, a flat gain curve within the frequency band, and a maximum gain of 7.14 dBi, achieving excellent radiation performance. Starting with a rectangular, substrate-integrated waveguide antenna with a simple structure, the bandwidth expansion performance of an open-type substrate-integrated waveguide antenna was verified. Furthermore, the impedance bandwidth can be increased by simply removing some metal pillars, without adding a complex matching network or special structures. This is simple and low-cost to manufacture, providing further possibilities for future wideband antenna designs.

[0038] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Those skilled in the art can make various changes and modifications to the present invention. All modifications, equivalent replacements, improvements, etc. made within the spirit and scope of the present invention are intended to be included in the scope of the claims of the present invention.

Claims

1. An open-type small wideband antenna using a substrate-integrated waveguide, comprising a base layer dielectric substrate (4) and an upper layer dielectric substrate (6), a first metal layer (1) provided on the lower surface of the base layer dielectric substrate (4), and a second metal layer (2) provided on the upper surface of the base layer dielectric substrate (4); The second metal layer (2) has a cleaved strip-shaped open-circuit slit (11), and the slit (11) functions as a radiation surface for the first metal layer (1), the second metal layer (2), and the underlying dielectric substrate (4). A plurality of metal cylinders penetrate the underlying dielectric substrate (4), and the upper and lower ends of the plurality of metal cylinders are connected to the first metal layer (1) and the second metal layer (2), respectively, to form a SIW resonator. The second metal layer (2) is a coplanar waveguide feed structure. The open-type small wideband antenna using a substrate-integrated waveguide is characterized in that the side of the strip-shaped open circuit away from the slit (11) is connected to a microstrip line feed (7) so as to form a structure, the upper layer dielectric substrate (6) is attached to the upper surface of the second metal layer (2) and is attached to the cleaved strip-shaped open circuit slit (11) of the second metal layer (2), and the upper surface of the upper layer dielectric substrate (6) is a third metal layer (3).

2. The open-type small wideband antenna using a substrate-integrated waveguide as described in claim 1, characterized in that the third metal layer (3) is composed of two T-shaped metal patches (9) arranged at an interval equal to the width of the slit (8), and four metal short-circuiting through holes (10) are provided in the upper layer dielectric substrate (6), and the four metal short-circuiting through holes (10) penetrate the upper layer dielectric substrate (6).

3. 3. The open-type small wideband antenna using a substrate-integrated waveguide according to claim 2, wherein the width of the slit (11) of the strip-shaped open circuit is the same as the width of the slit (8).

4. The open-type small wideband antenna using a substrate-integrated waveguide according to claim 3, characterized in that the widths of the strip-shaped open circuit slit (11) and the slit (8) are both 1.55 mm to 1.75 mm.

5. 2. The open-type small wideband antenna using a substrate-integrated waveguide according to claim 1, wherein the underlayer dielectric substrate (4) on the same side as the microstrip line feed (7) is not provided with a metal cylinder so as to form an open structure, the underlayer dielectric substrate (4) on the same side as the microstrip line feed (7) is not provided with a metal cylinder at the slit (11) of the strip-shaped open circuit so as to form an open structure, and the underlayer dielectric substrate (4) on the opposite side from the microstrip line feed (7) is provided with three metal cylinders on each side of a symmetry axis that passes through the longitudinal center of the slit (11) of the strip-shaped open circuit and is perpendicular to the longitudinal direction.

6. 2. The open-type small wideband antenna using a substrate-integrated waveguide according to claim 1, wherein the size of the upper layer dielectric substrate (6) is 1 / 4.5 of the size of the underlying layer dielectric substrate (4).

7. 2. The open-type small wideband antenna using a substrate-integrated waveguide according to claim 1, wherein the impedance of the microstrip line feed (7) and the terminal is both 50 ohms.

8. 8. The open-type small wideband antenna using the substrate-integrated waveguide according to claim 1, wherein the open-type small wideband antenna covers the X band.

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