SIW antenna unit with polarization variable along with frequency

Abstract

The invention relates to an SIW (substrate integrated waveguide) antenna unit with variable polarization along with frequency, which comprises an upper radiation structure, a dielectric substrate, a lower metal floor, an excitation port and a metal through hole, and is characterized in that the upper radiation structure and the lower metal floor are respectively attached to two sides of the dielectric substrate and are connected through the metal through hole penetrating through the dielectric substrate; the excitation port is used for excitation, the part surrounded by the metal through hole forms the substrate integrated waveguide, and a signal input by the excitation port is transmitted through the substrate integrated waveguide. The SIW antenna unit comprises the upper-layer radiation structure, the lower-layer floor and the periodically arranged metal through holes, and the structure is simple; by designing the SIW structure distribution, polarization switching under different frequency points can be realized, so that a multi-polarization radiation function can be realized in a broadband range; the device has the advantages of low cost, simple structure, easiness in processing and manufacturing, high integration level, low loss and the like, and has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave antennas, and in particular to a SIW antenna unit with variable polarization depending on frequency. Background Art

[0002] With the rapid development of mobile communication technology in the new era, low-frequency wireless spectrum resources are gradually exhausted, and millimeter waves have broad application prospects and potential in the field of mobile communications due to their advantages such as short wavelength, wide bandwidth and low interference, and have gradually attracted the attention of researchers in this field. Therefore, on this basis, the design of miniaturized, high-performance, multi-polarized and multi-functional millimeter wave antennas has also become a future research and development trend, and a series of new related technologies have emerged, among which the most concerned is the Substrate Integrated Waveguide (SIW) technology.

[0003] SIW technology is a new type of waveguide structure proposed in recent years. Through the metallized vias and the bottom metal connection to form a substrate integrated waveguide back cavity structure, the traditional PCB processing technology or LTCC technology can be used to achieve surface wave suppression and improve antenna gain. It can be applied to microwave and millimeter wave bands. It has been widely used due to its low radiation, low insertion loss, high power capacity and easy integration. The structure can realize the integration of active and passive devices, thereby realizing microwave millimeter wave antenna and device design.

[0004] In areas where mobile communication base stations are densely distributed, the use of new antenna technology with multi-frequency multi-polarization antennas can enable the antenna's transceiver channel to operate in duplex or multi-mode, which can effectively save the number of antennas for a single directional base station and reduce costs. At the same time, multi-polarization antennas can reduce losses, reduce interference, and improve the quality of mobile communications. Therefore, the design of multi-frequency multi-polarization antennas based on SIW is an important part of the mobile communication field. However, the design of such antennas in the prior art has the problems of complex structure and high cost, which is not conducive to production and use. Therefore, it is necessary to design a multi-frequency multi-polarization antenna based on SIW that is simple in structure and easy to produce. Summary of the invention

[0005] In order to solve the existing technical problems, the present invention provides a SIW antenna unit with variable polarization depending on frequency.

[0006] The specific contents of the present invention are as follows: A SIW antenna unit with variable polarization with frequency, comprising an upper radiation structure, a dielectric substrate, a lower metal floor, an excitation port and a metal through hole, wherein the upper radiation structure and the lower metal floor are respectively attached to two sides of the dielectric substrate and connected through a metal through hole penetrating the dielectric substrate, and the excitation port is used for excitation, and the portion surrounded by the metal through hole forms a substrate integrated waveguide, and the signal input by the excitation port is transmitted via the substrate integrated waveguide.

[0007] Furthermore, the upper radiation structure is realized by opening a rectangular radiation slot on the metal plate; the signal input from the excitation port realizes effective radiation of electromagnetic waves through the rectangular radiation slot in the upper radiation structure.

[0008] Furthermore, the metal through holes have a uniform spacing and are periodically arranged on the antenna unit.

[0009] Furthermore, the excitation port is transitioned through the metal cuboid structure and the metal cylindrical via in the metal through hole, the metal cuboid structure is arranged at the excitation port, the metal cylindrical via is arranged behind the metal cuboid structure, and the metal cylindrical via is arranged periodically.

[0010] Furthermore, the length L1 of the rectangular radiation slot is 2.3 mm, the width W1 is 1.9 mm, the length D1 of the antenna unit is 15 mm, the width D2 is 15 mm, the length L2 of the metal rectangular structure is 0.6 mm, the width W2 is 0.3 mm, the height H is 0.635 mm, the diameter D3 of the metal cylindrical via is 0.4 mm, and the periodic interval L3 between the metal cylindrical vias is 0.7 mm.

[0011] Furthermore, the upper radiation structure and the lower metal floor are respectively printed on the upper and lower surfaces of the dielectric substrate by a microwave dielectric plate printing process.

[0012] The SIW antenna unit of the present invention comprises an upper radiation structure, a lower floor and periodically arranged metal through holes, and has a simple structure. By designing the SIW structure distribution, polarization switching at different frequencies can be achieved, so that the function of multi-polarization radiation can be achieved within a broadband range. It has the advantages of low cost, simple structure, easy processing and manufacturing, high integration and low loss, and has a good prospect for use. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The specific implementation of the present invention will be further explained below in conjunction with the accompanying drawings.

[0014] Figure 1 It is a structural diagram of the SIW antenna unit of the present invention.

[0015] Figure 2 FIG. 4 is a side view of the SIW antenna unit of the present invention.

[0016] Figure 3 FIG. 4 is a top view of the SIW antenna unit of the present invention.

[0017] Figure 4 It is a schematic diagram of the standing wave changing with frequency according to the present invention.

[0018] Figure 5 It is a schematic diagram showing that the horizontal polarization gain, vertical polarization gain and total gain of the present invention vary with frequency.

[0019] Figure 6 It is a schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe in the horizontal plane of 42 GHz according to the present invention.

[0020] Figure 7 It is a schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe in the vertical plane at 42 GHz of the present invention.

[0021] Figure 8 It is a schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe in the horizontal plane at 46.5 GHz of the present invention.

[0022] Fig. 9 It is a schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe in the vertical plane at 46.5 GHz of the present invention.

[0023] Fig.10 It is a schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe in the horizontal plane of 48 GHz according to the present invention.

[0024] Fig.11 It is a schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe in the vertical plane at 48 GHz of the present invention. DETAILED DESCRIPTION

[0025] Combination Figure 1-Figure 3 The SIW antenna unit with variable polarization with frequency of the present invention has a length and a width of D1 and D2 respectively, and includes an upper radiation structure 1, a dielectric substrate 2, a lower metal floor 3, an excitation port 4 and a metal through hole 5. The upper radiation structure 1 and the lower metal floor 3 are respectively attached to the two sides of the dielectric substrate 2 and are connected through the metal through hole 5 penetrating the dielectric substrate 2. The excitation port 4 is used for excitation, and the part surrounded by the metal through hole 5 forms a substrate integrated waveguide. The signal input by the excitation port 4 is transmitted via the substrate integrated waveguide.

[0026] In this embodiment, the upper radiation structure 1 is preferably realized by opening a rectangular radiation slot 12 with a length and a width of L1 and W1 respectively on the metal plate 11; the signal input from the excitation port 4 realizes effective radiation of electromagnetic waves through the rectangular radiation slot 12 in the upper radiation structure 1. The rectangular radiation slot 12 falls into the area surrounded by the metal through hole 5.

[0027] Preferably, in this embodiment, the metal through holes 5 have uniform spacing and are periodically arranged on the antenna unit.

[0028] In this embodiment, the excitation port 4 is preferably transitioned through the metal rectangular parallelepiped structure 51 and the metal cylindrical via 52 in the metal through hole 5. The metal rectangular parallelepiped structure 51 is arranged at the excitation port 4, and the metal cylindrical via 52 is arranged behind the metal rectangular parallelepiped structure 51. The metal cylindrical vias 52 are arranged periodically. The length, width and height of the metal rectangular parallelepiped structure 51 are L2, W2 and H respectively, the diameter of the metal via 52 is D3, and the periodic interval between the metal vias 52 is L3. Among them, H is also the thickness of the antenna unit, and the periodic interval L3 refers to the distance between the centers of two adjacent metal vias 52. The metal through hole 5 is arranged in an L shape on the antenna unit as a whole, wherein the two metal rectangular parallelepiped structures 51 are located at the edge of the antenna unit and connected to the excitation port 4, and the metal cylindrical vias 52 are evenly arranged with the same spacing behind the two metal rectangular parallelepiped structures 51, and extend in the direction of the rectangular radiation slot 12 to surround the rectangular radiation slot 12.

[0029] The portion surrounded by the metal through hole 5 is constructed as a substrate integrated waveguide. The signal is input through the excitation port 4. After the signal is transmitted through the substrate integrated waveguide, the electromagnetic wave is effectively radiated through the rectangular radiation slot 12 of the upper radiation structure 1. Due to the broadband transmission characteristics of the substrate integrated waveguide, the change of the operating frequency causes the electromagnetic wave to form different transmission modes inside it, thereby forming different excitation forms at the position of the rectangular radiation slot, forming different polarizations, and converting from horizontal polarization to vertical polarization as the operating frequency increases.

[0030] In this embodiment, the upper radiation structure 1 and the lower metal floor 3 are respectively printed on the upper and lower surfaces of the dielectric substrate 2 by a microwave dielectric plate printing process. The microwave dielectric plate printing process is adopted, and only a double-layer structure is used to achieve the corresponding functions, which has the advantage of high integration.

[0031] The following table shows the specific parameters of the antenna subarray in the embodiment of the present invention. The operating frequency of the antenna unit is 41.7 GHz to 48.8 GHz, and as the antenna radiation frequency changes, the polarization of its radiation will also change accordingly, gradually transitioning from horizontal linear polarization to vertical linear polarization.

[0032] Table 1 Parameters of the radiation unit

[0033] like Figure 4As shown in the standing wave ratio curve of the SIW antenna unit of the present invention, it can be seen from the standing wave ratio curve of the input port that a standing wave coefficient less than 2 can be achieved in the frequency band range of 41.7 GHz to 48.8 GHz, which proves that it can achieve good matching performance within a relative bandwidth of 15.7%, ensuring that the input signal can be effectively transmitted to the substrate integrated waveguide structure to excite the antenna unit, thereby achieving good radiation performance.

[0034] like Figure 5 The gain and total gain of the SIW antenna unit of the present invention in the horizontal polarization and vertical polarization broadside directions vary with frequency as shown in the schematic diagram. It can be seen that within the operating frequency band, as the operating frequency increases, the synthetic total gain of the antenna remains basically unchanged, but the gain of the horizontal polarization gradually decreases, and the gain of the vertical polarization gradually increases. Since the antenna unit of the present invention has a wide operating bandwidth, the operating mode of the waveguide will also be different as the operating frequency changes. By reasonably designing the position of the metal vias in the substrate integrated waveguide, the electromagnetic wave energy of different operating modes can be coupled to the upper radiation structure, thereby stimulating its different polarizations to radiate. The present invention shows the directional patterns of horizontal polarization and vertical polarization in the horizontal and vertical planes and the synthetic total directional pattern at three typical operating frequencies of 42 GHz, 46.5 GHz and 48 GHz.

[0035] like Figure 6 The SIW antenna unit of the present invention is shown in the schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe in the horizontal plane at 42 GHz. From the displayed results, it can be seen that at the operating frequency of 42 GHz, the polarization of the antenna is horizontal polarization, and the beam gain in the broadside direction is basically the same as the total gain. At this time, the gain of cross polarization and vertical polarization is reduced by more than 15 dB compared with the gain of the main polarization, i.e., horizontal polarization.

[0036] like Figure 7 The SIW antenna unit of the present invention is shown in the schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe in the vertical plane at 42 GHz. Similarly, it can be seen from the displayed results that at the operating frequency of 42 GHz, the polarization of the antenna is horizontal polarization, and the beam gain in the broadside direction is basically the same as the total gain. At this time, the gain of the cross polarization and the vertical polarization is reduced by more than 15 dB compared with the gain of the main polarization, i.e., the horizontal polarization.

[0037] like Figure 8 The SIW antenna unit of the present invention is shown in the schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe of the horizontal plane at 46.5 GHz. From the displayed results, it can be seen that at the operating frequency of 46.5 GHz, the energy emitted in the side-beam direction of the horizontal polarization and vertical polarization of the antenna on the horizontal plane is the same, which is about 3 dB lower than the total gain of the antenna.

[0038] like Fig. 9 The SIW antenna unit of the present invention is shown in the schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe of the vertical plane at 46.5 GHz. From the displayed results, it can be seen that at the operating frequency of 46.5 GHz, the energy emitted in the side-fire direction of the horizontal polarization and vertical polarization of the antenna on the vertical plane is the same, which is about 3 dB lower than the total gain of the antenna.

[0039] like Fig.10 The SIW antenna unit of the present invention is shown in the schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe at 48 GHz horizontal plane. From the displayed results, it can be seen that at the operating frequency of 48 GHz, the polarization of the antenna is vertical polarization, and the beam gain in the broadside direction is basically the same as the total gain. At this time, the gain of cross polarization and horizontal polarization is reduced by more than 15 dB compared with the gain of main polarization, i.e. vertical polarization.

[0040] like Fig.11 The SIW antenna unit of the present invention is shown in the schematic diagram of horizontal polarization, vertical polarization and synthetic total lobe in the vertical plane at 48 GHz. Similarly, it can be seen from the displayed results that at the operating frequency of 42 GHz, the polarization of the antenna is vertical polarization, and the beam gain in the broadside direction is basically the same as the total gain. At this time, the gain of cross polarization and horizontal polarization is reduced by more than 15 dB compared with the gain of the main polarization, i.e., vertical polarization.

[0041] Compared with the prior art, the present invention has the following significant advantages: 1. High integration: The SIW antenna unit structure with variable polarization with frequency of the present invention adopts a microwave dielectric board printing process, and can realize the corresponding function using only a double-layer structure, which has the advantage of high integration; 2. Simple structure and easy processing: The SIW antenna unit structure with variable polarization with frequency of the present invention is composed of an upper radiation structure, a lower floor and periodically arranged metal through holes. It has a simple structure and can be realized by using mature microwave dielectric plate processing technology; 3. Low profile and light weight: The frequency-variable polarization SIW antenna unit of the present invention adopts a microwave dielectric plate printing process, and only includes a single-layer dielectric plate and upper and lower two-layer metal structures, avoiding various structural accessories in conventional integration methods, and effectively reducing the weight of the antenna; 4. Broadband multi-polarization: The SIW antenna unit with variable polarization with frequency of the present invention can realize polarization switching at different frequencies by designing the SIW structure distribution, so that the function of multi-polarization radiation can be realized within a broadband range.

[0042] Many specific details are described in the above description to facilitate a full understanding of the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person familiar with the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A SIW antenna unit with variable polarization according to frequency, characterized in that: The invention comprises an upper radiation structure (1), a dielectric substrate (2), a lower metal floor (3), an excitation port (4) and a metal through hole (5); the upper radiation structure (1) and the lower metal floor (3) are respectively attached to two sides of the dielectric substrate (2) and are connected via a metal through hole (5) penetrating the dielectric substrate (2); the excitation port (4) is used for excitation; the portion surrounded by the metal through hole (5) forms a substrate integrated waveguide; and the signal inputted from the excitation port (4) is transmitted via the substrate integrated waveguide.

2. The SIW antenna unit with variable polarization according to claim 1, characterized in that: The upper radiation structure (1) is realized by opening a rectangular radiation slot (12) on a metal plate (11); the signal input from the excitation port (4) realizes effective radiation of electromagnetic waves through the rectangular radiation slot (12) in the upper radiation structure (1).

3. The SIW antenna unit with variable polarization according to claim 2, characterized in that: The metal through holes (5) have a uniform spacing and are periodically arranged on the antenna unit.

4. The SIW antenna unit with variable polarization according to claim 2, characterized in that: The excitation port (4) is transitioned through the metal rectangular parallelepiped structure (51) and the metal cylindrical via hole (52) in the metal through hole (5); the metal rectangular parallelepiped structure (51) is arranged at the excitation port (4); the metal cylindrical via hole (52) is arranged behind the metal rectangular parallelepiped structure (51); and the metal cylindrical via holes (52) are arranged periodically.

5. The SIW antenna unit with variable polarization according to claim 4, characterized in that: The length L1 of the rectangular radiation slot (12) is 2.3 mm, and the width W1 is 1.9 mm; the length D1 of the antenna unit is 15 mm, and the width D2 is 15 mm; the length L2 of the metal rectangular parallelepiped structure (51) is 0.6 mm, the width W2 is 0.3 mm, and the height H is 0.635 mm; the diameter D3 of the metal cylindrical via (52) is 0.4 mm, and the periodic interval L3 between the metal cylindrical vias (52) is 0.7 mm.

6. The SIW antenna unit with variable polarization according to claim 1, characterized in that: The upper radiation structure (1) and the lower metal floor (3) are respectively printed on the upper and lower surfaces of the dielectric substrate (2) by means of a microwave dielectric plate printing process.

Images