Wideband dual-band 5g antenna with large frequency ratio

Abstract

The application provides a large-frequency-ratio wide dual-band 5G antenna, comprising a main antenna, a folding probe and a feeding substrate; the main antenna comprises a bottom surface, a rectangular slot is arranged at the center of the bottom surface, a WR-34 waveguide is arranged in the rectangular slot, an open structure composed of two inclined plate electric dipoles is arranged on the bottom surface, and planar magnetic dipoles are respectively arranged on the upper edges of the two inclined plate electric dipoles; the folding probe is two, and is respectively arranged on the two sides of the inclined plate electric dipole, and a square horn structure is formed by the inclined plate electric dipole and the folding probe; the feeding substrate is arranged on the upper surface of the bottom surface, and comprises a dielectric plate and a microstrip line printed on the dielectric plate. The application improves the gain of the millimeter wave band antenna while maintaining high isolation of two frequency bands, and the branch designed on the basis of the main probe limits the wave leaked from the side of the inclined horn antenna in the radiation area, thereby improving the gain of the inclined horn antenna.

Description

Technical Field

[0001] This application relates to the field of antennas, and more particularly to a high frequency-to-width dual-band 5G antenna. Background Technology

[0002] Microwave spectrum resources are becoming increasingly scarce, and bandwidth is limited, which restricts transmission rates. Millimeter waves have a higher absolute bandwidth than microwaves, providing wider channel bandwidth and higher transmission rates. Currently, 5G research and development has incorporated millimeter waves, and my country has also adopted a spectrum allocation strategy that considers both microwave and millimeter waves. Therefore, future communication systems must cover both microwave and millimeter wave bands simultaneously. This requires components in the communication system to have a high frequency ratio, such as antennas.

[0003] The traditional method for achieving a high frequency ratio dual-band antenna is to design two antennas in different frequency bands and then combine them vertically or horizontally. However, this method increases the size of the antenna in the communication system, and the manufacturing cost also increases accordingly.

[0004] In recent years, shared aperture antennas have been proposed to solve this problem. Shared aperture antennas reuse a local area of ​​a low-frequency antenna as a high-frequency antenna, so antennas designed in this way do not occupy additional space, thus achieving the goal of high antenna integration.

[0005] A compact, high-frequency-ratio antenna (Y.-X. Sun, KW Leung and K. Lu, “Compact Dual Microwave / Millimeter-Wave Planar Shared-Aperture Antenna for Vehicle-to-Vehicle / 5G Communications,” IEEE Transactions on Vehicular Technology, vol. 70, no. 5, pp. 5071-5076, May 2021.) was designed to cover the 5.9 GHz vehicle-to-vehicle communication band and the 28 GHz 5G band. The antenna designed in the aforementioned literature consists of three dielectric substrates. The bottom dielectric substrate serves as the feed layer, with microstrip lines printed above it to excite the feed probe. Two vertical rectangular metal apertures are fabricated on the other two dielectric substrates to form the magnetic dipoles of the microwave band magnetoelectric dipole antenna. Two parallel metal plates are introduced on either side of the rectangular metal apertures as electric dipoles. By adjusting the spacing between the two magnetic dipoles, a parallel plate resonant cavity is formed, thus constructing a millimeter-wave parallel plate resonant antenna. The magnetoelectric dipole antenna is excited by a folded probe, while the parallel-plate resonant antenna is fed by a pair of differentially fed L-shaped probes. This antenna achieves 41% bandwidth (5.30-8.08 GHz) in the low-frequency band, but the high Q value of the parallel-plate resonant antenna results in only 6% bandwidth (27.15-29.02 GHz) in the high-frequency band. This limits the antenna's capabilities, for example, it cannot cover the 5 GHz n257 band (26.5-29.5 GHz). To achieve broadband coverage in both frequency bands of a large frequency ratio antenna, a dielectric resonator (DRA) antenna with a centrally etched groove was proposed (LYFeng and KWLeung, “Wideband Dual-Frequency Antenna With Large Frequency Ratio,” IEEE Trans. Antennas Propag., vol. 67, no. 3, pp. 1981-1986, Mar. 2019.). A copper foil layer was then attached around the groove to form a millimeter-wave Fabry-Perot resonator (FPRA) covering the 2.4 / 24 GHz ISM band. The low-frequency DRA was further improved by incorporating TE... 111 x Pattern and TE 113 xThe first mode achieved a bandwidth of 38.24%. The high-frequency FPRA achieved a bandwidth of 16.18% by simultaneously exciting two L-probe modes and the FPRA mode. However, the rectangular slots on the DRA generate strong cross-polarization fields, thus affecting the DRA's radiation performance. Furthermore, the copper foil forming the FPRA metal plate is prone to detaching from the DRA surface due to manufacturing issues, which also affects the antenna's stable radiation performance. Summary of the Invention

[0006] The purpose of this application is to overcome the deficiencies in the prior art and provide a high frequency-to-width dual-band 5G antenna.

[0007] This application provides a high frequency ratio wide dual-band 5G antenna, including: a main antenna, a folded probe and a feed substrate;

[0008] The main antenna includes a bottom surface, a rectangular slot is provided in the center of the bottom surface, a WR-34 waveguide is provided in the rectangular slot, an open structure composed of two inclined plate electric dipoles is provided on the bottom surface, and planar magnetic dipoles are respectively provided on the upper edges of the two inclined plate electric dipoles.

[0009] There are two folded probes, which are respectively disposed on both sides of the inclined plate electric dipole, and the inclined plate electric dipole and the folded probes form a square trumpet-shaped structure;

[0010] The power supply substrate is disposed on the upper surface of the bottom surface and includes a dielectric substrate and microstrip lines printed on the dielectric substrate.

[0011] Optionally, the folded probe includes an L-shaped main strip with multiple L-shaped branch structures.

[0012] Optionally, the thickness of the main strip and the branch structure is 0.5 mm.

[0013] Optionally, a rectangular groove is provided at the center of the bottom surface, and a waveguide is provided in the rectangular groove.

[0014] Optionally, the folded probe is fixed to the inclined plate dipole by bolts.

[0015] Optionally, a feed hole is provided at one end of the microstrip line, and SMA is used for power feeding.

[0016] Optionally, the dielectric substrate is made of Taconic RF-60 with a thickness of 0.64 mm.

[0017] Optionally, the SMA is connected to a 50-ohm 0.85mm microstrip line, and then connected to a 50-ohm microstrip line with a phase difference of 180° via two quarter-wavelength 0.44mm conversion lines, and finally connected to the folded probe.

[0018] Optionally, the length and width of the bottom surface are Lg = 150mm and Wg = 150mm, respectively.

[0019] Optionally, the distance between the folded probe and the magnetic dipole is d = 1.2 mm.

[0020] The advantages and beneficial effects of this application are as follows:

[0021] This application provides a high frequency ratio wide dual-band 5G antenna, comprising: a main antenna, folded probes, and a feeding substrate; the main antenna includes a bottom surface, a rectangular slot is provided at the center of the bottom surface, a WR-34 waveguide is provided in the rectangular slot, and an open structure composed of two inclined plate electric dipoles is provided on the bottom surface, with planar magnetic dipoles respectively provided on the upper edges of the two inclined plate electric dipoles; two folded probes are respectively provided on both sides of the inclined plate electric dipoles, forming a square horn-shaped structure with the inclined plate electric dipoles and the folded probes; the feeding substrate is provided on the upper surface of the bottom surface, including a dielectric substrate and microstrip lines printed on the dielectric substrate. This application can improve the gain of millimeter-wave antennas while maintaining high isolation between the two frequency bands. Its feeding method is a pair of differentially fed folded multi-segment probes, wherein differential feeding eliminates the asymmetry of the magnetoelectric dipole pattern, and the two branches designed on the basis of the main probe can limit the waves leaking from the side of the inclined horn antenna to the radiation area, thereby improving the gain of the inclined horn antenna. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a high frequency-to-width dual-band 5G antenna in this application.

[0023] Figure 2 This is a schematic diagram of the folded probe structure in this application.

[0024] Figure 3 This is a schematic diagram of the feed dielectric board structure in this application.

[0025] Figure 4 This is a schematic diagram of the gain and VSWR of the tilted horn antenna and the probe with and without a loaded stub in this application.

[0026] Figure 5 This is a schematic diagram of the simulated VSWR and gain of the microwave band magnetoelectric dipole antenna in this application.

[0027] Figure 6 This is a schematic diagram of the simulated VSWR and gain of the high-frequency tilting horn antenna in this application.

[0028] Figure 7a This is a schematic diagram of the E-plane radiation pattern of the 2.1 GHz analog antenna in this application.

[0029] Figure 7b This is a schematic diagram of the H-plane radiation pattern of the 2.1 GHz analog antenna in this application.

[0030] Figure 8a This is a schematic diagram of the E-plane radiation of the 32GHz analog antenna in this application.

[0031] Figure 8b This is a schematic diagram of the H-plane radiation of the 32GHz analog antenna in this application. Detailed Implementation

[0032] The present application will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present application.

[0033] The following are examples of specific implementation processes provided to illustrate the technical solutions to be protected in this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can implement this application by different technical means under the guidance of the concept of this application. Therefore, this application is not limited to the specific embodiments below.

[0034] This application provides a high frequency ratio wide dual-band 5G antenna, comprising: a main antenna, folded probes, and a feeding substrate; the main antenna includes a bottom surface, a rectangular slot is provided at the center of the bottom surface, a WR-34 waveguide is provided in the rectangular slot, and an open structure composed of two inclined plate electric dipoles is provided on the bottom surface, with planar magnetic dipoles respectively provided on the upper edges of the two inclined plate electric dipoles; two folded probes are respectively provided on both sides of the inclined plate electric dipoles, forming a square horn-shaped structure with the inclined plate electric dipoles and the folded probes; the feeding substrate is provided on the upper surface of the bottom surface, including a dielectric substrate and microstrip lines printed on the dielectric substrate. This application can improve the gain of millimeter-wave antennas while maintaining high isolation between the two frequency bands. Its feeding method is a pair of differentially fed folded multi-segment probes, wherein differential feeding eliminates the asymmetry of the magnetoelectric dipole pattern, and the two branches designed on the basis of the main probe can limit the waves leaking from the side of the inclined horn antenna to the radiation area, thereby improving the gain of the inclined horn antenna.

[0035] Figure 1 This is a schematic diagram of a high frequency-to-width dual-band 5G antenna in this application.

[0036] Please refer to Figure 1 As shown, the antenna consists of three parts: the main body of the antenna, the multi-segment folded probe, and the feed substrate.

[0037] The main body of the antenna can be machined from aluminum plates. This antenna integrates a microwave-band magnetoelectric dipole antenna and a millimeter-wave-band tilted-plane horn antenna. The magnetoelectric dipole antenna is placed on a base surface with a length and width of Lg = 150 mm and Wg = 150 mm, respectively. The magnetoelectric dipole antenna consists of magnetic and electric dipoles. Two planar dipoles constitute the electric dipole of the magnetoelectric dipole antenna, with a length of Ld = 71 mm and a width of Wd = 35 mm. The length and width of the dipoles can be fine-tuned based on quarter-wavelength and half-wavelengths of the center frequency to achieve optimal antenna performance. For the magnetic dipole section, two tilted conical metal plates with widths gradually decreasing from Wh = 37 mm serve as the magnetic dipoles, with a tilt angle of θ. Notably, the magnetic dipole section of the magnetoelectric dipole antenna is reused as a tilted-plane horn antenna in the millimeter-wave band, thus this dual-band antenna maintains a compact structure while achieving a high frequency ratio. To excite the tilted horn antenna, a rectangular slot is cut in the center of the bottom surface, and a WR-34 waveguide is placed at the center of the antenna for feeding. This main body can be directly manufactured by machining.

[0038] Please refer to Figure 2 As shown, the folded probe of the antenna is a multi-branch folded probe. The main folded probe is designed based on the Γ-type probe and consists of three strips with a thickness of 0.5 mm. Due to the tilted placement of the magnetic dipole, to ensure good performance of the magnetoelectric dipole antenna, the first part of the probe is parallel to the magnetic dipole, and this part together with the magnetic dipole forms a section of air microstrip line. The electrical signal is transmitted through the first part of the strip to the second part, and then coupled to the electric dipole. The third part is also parallel to the magnetic dipole, and the matching of the magnetoelectric dipole antenna can be adjusted by changing the length of this part.

[0039] To further improve the gain of the tilted horn antenna, two L-shaped branches were introduced into the main probe, each with a structure similar to the main probe. This multi-branch folded probe was manufactured using 3D printing technology, which allows for high precision.

[0040] Two multi-branched folded probes are placed on the side of the magnetic dipole, with a distance of d = 1.2 mm between the probes and the dipole. To secure the probes, holes are drilled in the probes, and they are connected to the magnetic dipole using screws and a fixing strip made of Teflon. Compared to directly soldering the probes, this method is simpler and offers higher stability.

[0041] In addition, since the probe of this application has a certain tilt angle with the bottom surface, there will be some error when fixing it with solder.

[0042] Please refer to Figure 3 As shown, this is the feeding substrate portion. A dielectric substrate of the same size as the bottom surface is placed on top of the bottom surface for printing the feeding microstrip line. The dielectric substrate material is Taconic RF-60 with a thickness of 0.64 mm. The SMA is connected to a 50-ohm 0.85 mm microstrip line, and then connected to a 50-ohm microstrip line with a 180° phase difference via two quarter-wavelength 0.44 mm transition lines, and finally connected to a multi-branch folded probe. A hole is punched at one end of the microstrip line to allow the SMA to be fed. Compared with directly soldering the SMA to the probe, this method is easier to solder and has higher stability. The 180° phase shifter ensures that the two probes have the same amplitude but different phase, thus giving the magnetoelectric dipole antenna a symmetrical radiation pattern.

[0043] Furthermore, the magnetoelectric dipole antenna section and the bottom section are fabricated separately. The bottom of the magnetic dipole can be disassembled with screws to facilitate the installation of the feed substrate. Compared with the method of disassembling the dielectric substrate into two parts for installation, the method of this application can ensure that the antenna performance is not affected, and the manufacturing process is simple.

[0044] To address the limitations of conventional dual-band antennas in certain 5G scenarios due to their low integration and small frequency ratio, this application innovatively proposes a broadband dual-band antenna with a frequency ratio of 14. This dual-band antenna consists of a microwave-band magnetoelectric dipole antenna and a millimeter-wave-band tilted horn antenna. Two tilted conical metal plates serve as magnetic dipoles in the microwave band and as tilted horn antennas in the millimeter-wave band. Both antennas share the same polarization. To avoid mutual coupling between the two antennas and its impact on antenna performance, a novel feeding method for the magnetoelectric dipole antenna is proposed. Unlike traditional Γ-shaped probes, a pair of differentially fed multi-branch folded probes are used to excite the magnetoelectric dipole antenna, maintaining good isolation between the two frequency bands. Furthermore, this feeding method improves the gain of the millimeter-wave-band tilted horn antenna.

[0045] Test results:

[0046] Please refer to Figure 4 As shown, to ensure that other parameters do not affect the performance of the high-frequency antenna, all antennas used in the comparison have the same aperture size. From Figure 4As can be seen, among the three antenna types, the tilted-plane horn antenna has the lowest gain. This is because the sides of the tilted-plane horn antenna are open, allowing waves to leak into free space. By adding a pair of electric dipoles and a pair of folded probes, the antenna gain is improved. Introducing electric dipoles is equivalent to lengthening the horn's size, and the electric dipoles help to make the electric field distribution at the horn aperture more uniform, both of which improve the gain of the high-frequency antenna. In addition, the folded probes can block some of the edge radiation of the wave. After introducing two stubs, the wave is properly confined within the horn's radiation aperture, with almost no wave leakage, thus the proposed antenna has the highest gain. Achieving a full-band gain improvement in a broadband antenna is quite rare.

[0047] Please refer to Figure 5 As shown, from Figure 5 It can be seen that the analog impedance bandwidth (VSWR<2) of the magnetoelectric dipole antenna is 1.61-2.45 GHz. The peak gain of the antenna can reach 9.62 dBi. The operating frequency of the magnetoelectric dipole antenna covers n1 (1.92-1.98 GHz), n2 (1.85-1.91 GHz), and n3 in the 5G band.

[0048] The n66 (1.71-1.78GHz), n70 (1.695-1.71GHz), and n84 (1.92-1.98GHz) bands have promising potential.

[0049] Please refer to Figure 7a and Figure 7b As shown, due to the use of differential feeding for the feed probe, symmetrical radiation patterns can be observed in both the E-plane and H-plane along the radiation direction.

[0050] Please refer to Figure 6 As shown in the figure, the VSWR of the tilted horn antenna is less than 2 in the 20-40GHz band, making it suitable for use as a broadband antenna in 5G applications, covering the entire FR2 band. Furthermore, the peak gain of the high-frequency tilted horn antenna reaches 17.2dBi.

[0051] Please refer to Figure 8a and Figure 8b As shown, from Figure 8a and Figure 8b As can be seen, the antenna's E-plane and H-plane radiation patterns at 32 GHz exhibit directional radiation. The cross-polarization of both planes is below -10 dB, and stable results are also achieved at other frequency points within the operating band, verifying the feasibility of the tilted horn antenna in the millimeter-wave band.

Claims

1. A high frequency-to-width dual-band 5G antenna, characterized in that, include: Main antenna, folded probe and feed substrate; The main antenna includes a bottom surface, a rectangular slot is provided in the center of the bottom surface, a WR-34 waveguide is provided in the rectangular slot, an open structure composed of two inclined plate electric dipoles is provided on the bottom surface, and planar magnetic dipoles are respectively provided on the upper edges of the two inclined plate electric dipoles. There are two folded probes, which are respectively disposed on both sides of the inclined plate electric dipole, and the inclined plate electric dipole and the folded probes form a square trumpet-shaped structure; The power supply substrate is disposed on the upper surface of the bottom surface, including a dielectric substrate and microstrip lines printed on the dielectric substrate; The folded probe includes an L-shaped main strip with multiple L-shaped branch structures on it; the thickness of the main strip and the branch structures is 0.5 mm; and the distance between the folded probe and the magnetic dipole is d = 1.2 mm.

2. The high frequency-to-width dual-band 5G antenna according to claim 1, characterized in that, A rectangular groove is provided at the center of the bottom surface, and a waveguide is provided in the rectangular groove.

3. The high frequency-to-width dual-band 5G antenna according to claim 1, characterized in that, The folded probe is fixed to the inclined plate dipole by bolts.

4. The high frequency-ratio dual-band 5G antenna according to claim 1, characterized in that, A power feed hole is provided at one end of the microstrip line, and SMA is used for power feeding.

5. The high frequency-ratio wide-band dual-band 5G antenna according to claim 4, characterized in that, The dielectric substrate is made of Taconic RF-60 and has a thickness of 0.64 mm.

6. The high frequency-ratio dual-band 5G antenna according to claim 4, characterized in that, The SMA is connected to a 50-ohm 0.85mm microstrip line, and then connected to a 50-ohm microstrip line with a phase difference of 180° via two quarter-wavelength 0.44mm conversion lines, and finally connected to the folded probe.

7. The high frequency-to-width dual-band 5G antenna according to claim 1, characterized in that, The length and width of the bottom surface are Lg = 150mm and Wg = 150mm, respectively.

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