CN115548678A - Wide-angle scanning millimeter wave array antenna structure - Google Patents

Abstract

The invention relates to a wide-angle scanning millimeter wave array antenna structure which comprises a plurality of antenna units which are arranged and connected at intervals, wherein each antenna unit comprises a first dielectric layer, a bonding layer and a second dielectric layer which are sequentially arranged from top to bottom, the top surface of the first dielectric layer is provided with a radiation patch layer, the second dielectric layer is provided with a coupling short-circuit structure and a coupling feed structure which are symmetrical about the center, and in addition, the antenna units are sequentially connected through an anti-symmetrical neutral line. Compared with the prior art, the antenna adopts the coupling short circuit structure to reduce the vertical current component, thereby reducing the high cross polarization component of the H surface and improving the radiation characteristic of the antenna unit; the size of the antenna units is further reduced by adopting a coupling feed mode, the side lobe level when the wave beam is scanned to a large angle is reduced by reducing the distance between the antenna units, and the wide wave beam scanning capability of the array antenna is expanded; the mutual coupling between the antenna units is improved by using the asymmetric neutralization line, and the mutual influence between the adjacent antenna units is reduced.

Description

A Wide Angle Scanning Millimeter Wave Array Antenna Structure

technical field

The invention relates to the technical field of antenna design, in particular to a wide-angle scanning millimeter-wave array antenna structure.

Background technique

In recent years, millimeter-wave antennas with beam scanning characteristics have received extensive research and attention. Among them, for mobile terminal devices such as mobile phones, most of the space is reserved for batteries, cameras, screens, etc., and the antenna design space is very limited, and the posture of the terminal device in use is arbitrary. In order to avoid the antenna being blocked and unable to effectively outward Radiation, millimeter-wave array antennas with small size and wide-angle scanning are a major problem facing the current terminal antenna design.

According to the principle of phased array, the fewer the number of units, the larger the unit interval, and the smaller the beam scanning range. Common millimeter-wave array antennas (such as Qualcomm QTM547 millimeter-wave antenna modules are mostly 4-unit arrays), in which the antenna units need to resonate based on 0.5 wavelengths, and the unit spacing is 0.5 wavelengths to form an array, resulting in a larger array size and limited Beam scan range. On the premise of not increasing the number of units, if you want to expand the beam scanning range, you need to reduce the unit spacing. For array antennas with small spacing, the difficulty lies in: how to improve the wide beam on the basis of realizing miniaturized antenna units. Scanning ability, while effectively reducing the coupling between antenna elements.

For this reason, in the prior art, for the microstrip patch antenna resonant at 0.5 wavelength, a short-circuit wall is added to the ground at its central electric field of 0, which will not affect its mode distribution, and at the same time, the patch size can be reduced to half of the original , so as to realize the direct short-circuit microstrip patch antenna based on 0.25 wavelength resonance, but because the short-circuit column will introduce a large vertical current component, resulting in a high H-plane cross-polarization component, which will affect the radiation characteristics of the antenna unit.

Contents of the invention

The purpose of the present invention is to provide a wide-angle scanning millimeter-wave array antenna structure to overcome the above-mentioned defects in the prior art, which can optimize the size of the array antenna, effectively improve the radiation characteristics of the antenna units, and reduce the coupling between the antenna units.

The purpose of the present invention can be achieved through the following technical solutions: a wide-angle scanning millimeter-wave array antenna structure, including a plurality of antenna units arranged and connected at intervals, and the antenna units include the first medium arranged in sequence from top to bottom layer, an adhesive layer and a second dielectric layer, the top surface of the first dielectric layer is provided with a radiation patch layer, and the second dielectric layer is provided with a coupling short-circuit structure and a coupling feeding structure symmetrical about the center.

Further, the top surface of the second dielectric layer is respectively provided with a coupling short-circuit patch layer and a coupling feed patch layer, and the bottom surface of the second dielectric layer is a metal ground layer.

Further, the coupling short-circuit patch layer and the coupling feed patch layer are respectively connected to the metal ground layer to respectively form a coupling short-circuit structure and a coupling feed structure.

Further, the coupling short-circuit patch layer is connected to the metal ground layer through a short-circuit column.

Further, the coupling feed patch layer is connected to the metal ground layer through probes.

Further, the top end and the bottom end of the probe penetrate through the coupling feed patch layer and the metal ground layer respectively.

Further, the antenna elements are sequentially connected through an anti-symmetrical neutral line.

Further, both ends of the neutralization line are respectively connected to the radiation patch layers of two adjacent antenna units.

Further, the center-to-center spacing between the antenna elements is ≥0.3 wavelengths.

Further, the number of the antenna units is ≥4.

Compared with the prior art, the present invention arranges the coupling short-circuit structure and the coupling feeding structure on the second dielectric layer of the antenna unit. On the one hand, the coupling short-circuit structure is used to replace the traditional direct short-circuit structure, which can effectively reduce the vertical current component, thereby reducing the The high cross-polarization component of the H plane improves the radiation characteristics of the antenna unit. On the other hand, the coupled feed structure is used to further reduce the size of the antenna unit while realizing the coupled feed.

In the present invention, an antisymmetric neutral line is sequentially connected between adjacent antenna units to introduce new coupling, and the newly introduced coupling and the original coupling are used to cancel each other, which can effectively reduce the mutual influence of coupling between antenna units and improve Isolation between closely spaced antenna elements.

In the present invention, the center distance between the antenna units is set to ≥0.3 wavelength, and the minimum setting is 0.3 wavelength to form a compact array antenna structure. By reducing the distance between the antenna units, the side lobe when the beam scans to a large angle can be effectively reduced Level, thereby expanding the wide beam scanning capability of the array antenna.

Description of drawings

Fig. 1 is the schematic diagram of antenna element design process among the present invention;

Fig. 2 is corresponding reflection coefficient simulation result in the design process of antenna unit in the present invention;

Fig. 3 is the corresponding H surface direction diagram of the antenna unit design process in the present invention;

Figure 4a and Figure 4b are schematic diagrams of the top surface structure of the antenna unit based on 0.25 wavelength resonance in the embodiment;

FIG. 5 is a schematic diagram of the side structure of an antenna unit based on 0.25 wavelength resonance in an embodiment;

6 is a schematic diagram of the top surface structure of the wide-angle scanning millimeter-wave array antenna in the embodiment;

7 is a schematic diagram of the side structure of the wide-angle scanning millimeter-wave array antenna in the embodiment;

8a, 8b and 8c are schematic diagrams of the neutral line design process of the wide-angle scanning millimeter-wave array antenna in the embodiment;

Figures 9a, 9b and 9c are the corresponding isolation simulation results during the neutral line design process of the wide-angle scanning millimeter-wave array antenna in the embodiment;

Fig. 10a and Fig. 10b are the simulation results of the radiation patterns of the wide-angle scanning millimeter-wave array antenna under different beams in the embodiment.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example

As shown in Figures 5, 6, and 7, a wide-angle scanning millimeter-wave array antenna structure includes a plurality of antenna units arranged and connected at intervals. The antenna unit includes a first dielectric layer, an adhesive layer, and a layer and the second dielectric layer, the top surface of the first dielectric layer is provided with a radiation patch layer (as shown in the antenna patch in Figure 5), and the second dielectric layer is provided with a coupling short-circuit structure and a coupling feed structure symmetrical about the center .

Specifically, the top surface of the second dielectric layer is respectively provided with a coupling short circuit patch layer and a coupling feed patch layer, the bottom surface of the second medium layer is a metal ground layer, and the coupling short circuit patch layer and the coupling feed patch layer are respectively It is connected with the metal ground layer to respectively form a coupled short-circuit structure and a coupled feed structure.

Among them, the coupling short-circuit patch layer is connected to the metal ground layer through the short-circuit column, and the coupling feed patch layer is connected to the metal ground layer through the probe. Ground floor.

In addition, the antenna units are sequentially connected through an antisymmetric neutral line (as shown in FIG. 6 ), and both ends of the neutral line are respectively connected to the radiation patch layers of two adjacent antenna units.

In practical applications, the center-to-center spacing between antenna elements is ≥0.3 wavelengths, and the number of antenna elements is ≥4. In this embodiment, the center distance between the antenna units is designed to be 0.3 wavelength, and four antenna units are arranged and linearly connected to form an array antenna structure, which can cover the 25.5-27.5 GHz millimeter wave frequency band.

FIG. 1 is a schematic diagram of the design process of the antenna unit in the present invention, wherein the antenna unit is evolved from a common patch antenna based on 0.5 wavelength resonance. In the prior art, for an ordinary patch antenna working in TM01 mode, the symmetrical central electric field is 0, and adding a short-circuit wall to the ground here will not affect the mode distribution of the patch antenna, and at the same time, the size of the patch antenna can be reduced to the original half. However, since the direct short-circuit structure will introduce a large vertical current component, the direct-short patch antenna based on the 0.25 wavelength resonance will generate a high cross-polarization component on the H plane. Therefore, the design of this technical solution uses a coupled short-circuit structure instead of a direct short-circuit structure, which can effectively reduce the vertical current component, thereby reducing the H-plane cross-polarization component.

Fig. 2 shows the corresponding reflection coefficient simulation structure in the antenna unit design process in the present invention, wherein, based on the common patch antenna of 0.5 wavelength resonance, the direct short circuit patch antenna based on 0.25 wavelength resonance and the coupled short circuit based on 0.25 wavelength resonance The patch antennas (that is, using this technical solution) are all tuned to the 25.5-27.5 GHz frequency band. It can be seen from FIG. 2 that this technical solution can effectively reduce the high cross-polarization component of the H plane.

Fig. 3 shows the H-plane pattern corresponding to the design process of the antenna unit in the present invention. Among them, the H-plane peak gain and cross-polarization level of the ordinary patch antenna are 7.7dBi and -17dB respectively; directly short-circuiting the patch antenna, the peak gain of the H-plane is only 2.7dBi due to the deflection of the pattern caused by the increase of asymmetry, At the same time, due to the vertical current component introduced by the short-circuit column, the H-plane cross-polarization level is as high as -2.2dB; and the coupled short-circuit patch antenna designed by this technical solution can significantly weaken the asymmetry of the short-circuit patch and reduce the vertical current at the same time Component, H-plane peak gain and cross-polarization level are 6.3dBi and -12.4dB, respectively, which are obviously improved.

Fig. 4 a, 4b and Fig. 5 are respectively the top surface and the side structural schematic diagrams of the coupled short-circuit patch antenna based on 0.25 wavelength resonance in the present embodiment, and the dimensions of each part in the figure are respectively: Lg=12, Wg=12, Lp=2.5 , Wp=2.7, Ls=0.6, Ws=2.7, Lf=1.6, Wf=1, h1=0.254, h2=0.101, h3=0.381, the unit is mm.

Figure 6 and Figure 7 are schematic diagrams of the top and side structures of the wide-angle scanning millimeter-wave array antenna in this embodiment, respectively. The dimensions of each part in the figure are: D=3.4, La=12.9, Wa=5, and the units are mm .

Therefore, the array antenna designed in this embodiment is composed of four patch antenna units, which are arranged linearly with a center-to-center spacing of 0.3 wavelengths to form an array antenna. Among them, each antenna unit is composed of three layers of dielectric substrates, which are antenna dielectric layer 1, adhesive layer and antenna dielectric layer 2 from top to bottom. The radiation patch layer is located on the top surface of the antenna dielectric layer 1, and the coupling short circuit patch The layer and the coupling feed patch layer are both located on the top surface of the antenna dielectric layer 2, and the bottom surface of the antenna dielectric layer 2 is a metal ground layer, and the antenna dielectric layer 1 and the antenna dielectric layer 2 are glued together through the adhesive layer. Each antenna unit has a probe that penetrates the metal ground and the antenna dielectric layer 2, and is combined with a coupling and feeding patch provided on the surface of the antenna dielectric layer 2 to realize probe coupling and feeding. The coupling short-circuit structure is composed of a short-circuit post connecting the coupling short-circuit patch on the surface of the antenna dielectric layer 2 and the metal ground. In the radiating patch layer, adjacent radiating patches are connected by antisymmetric neutral lines to improve the isolation between closely arranged antenna elements.

8a, 8b and 8c are schematic diagrams of the neutral line design process of the wide-angle scanning millimeter-wave array antenna in this embodiment. Due to the asymmetry of the array, the decoupling effect of the usual sequential connection of neutral lines on the same side is limited. Based on this, this technical solution adopts an anti-symmetrical neutral line structure to improve the isolation between antennas.

9a, 9b, and 9c show the corresponding isolation simulation results during the neutral line design process of the wide-angle scanning millimeter-wave array antenna in this embodiment. When there is no neutral line decoupling, the coupling between adjacent antenna elements is as high as -8.9dB, and the mutual influence between the antennas is large, resulting in the deterioration of the pattern and resonance characteristics of the array antenna; when using the neutral line decoupling on the same side, the antenna The isolation has been improved, but the mutual coupling between the middle antenna units is still as high as -10.2dB; considering the asymmetry of the array, the antisymmetric neutral line structure adopted in this technical solution can effectively reduce the mutual coupling between the antenna units, so that the The isolation between adjacent antenna elements is better than 14.5dB. That is to say, this technical solution uses an asymmetric neutral line to introduce new coupling between closely placed adjacent antenna elements, changes the original coupling by controlling the size of the patch antenna, and adjusts the size of the two to make the newly introduced coupling and the original coupling offset each other (in actual design and application, the length and height of the neutralization line can be directly adjusted, and the adjustment of the size of the antenna radiation patch is adjusted together with the position movement of the coupling short-circuit structure to ensure that the operating frequency band of the antenna unit remains unchanged), namely The mutual coupling between antenna elements can be improved from -8.9dB without neutral line decoupling to below -15dB.

Figures 10a and 10b show the radiation direction simulation diagrams of the wide-angle scanning millimeter-wave array antenna in this embodiment under different beam directions. It can be seen that within the beam scanning range of -60° to 60°, the peak gain fluctuation is only 1.6dB. The sidelobe level is better than -7.7dB, and the cross-polarization isolation is greater than 12dB. The array has good gain, lower sidelobe level and lower cross-polarization level.

It can be seen from the above that the wide-angle scanning millimeter-wave array antenna in this embodiment is designed and implemented based on a miniaturized coupled short-circuit patch antenna with 0.25 wavelength resonance. First, use a coupled short-circuit structure instead of a direct short-circuit to reduce the high cross-polarization component on the H-plane of the patch antenna based on 0.25 wavelength resonance;

Secondly, in order to reduce the size of the array and expand the scanning range of the beam, the array antenna adopts an element spacing of 0.3 wavelengths to form an array, which can effectively reduce the side lobe level when the beam scans to a large angle and realize wide-angle scanning. Arrangement, the mutual influence will increase, which will lead to the deterioration of the resonance and radiation characteristics of the antenna units. Therefore, the antisymmetric neutral line structure is designed to reduce the mutual coupling between the antenna units, improve the isolation between the antenna units, and ensure the array characteristics. The millimeter-wave array antenna proposed in this technical solution has greatly improved antenna size, beam scanning range and decoupling performance.

It should be noted that the distance between the centers of the antenna elements in this embodiment is 0.3 wavelength, which is a very small value. It is very difficult to decouple under such a small distance between the elements. The connection between units can be effectively decoupled, and for the case where the unit spacing is greater than 0.3 wavelengths, the difficulty of decoupling decreases accordingly, and the antisymmetric neutral line decoupling proposed in this technical solution is also more applicable; in addition, this embodiment In order to meet the application requirements of the mobile terminal for the small size of the millimeter wave antenna, only 4 antenna units are used, but the application of this technical solution can be extended to the case where the number of antenna units is greater than 4.

The technical solution of the present invention is not limited to the limitations of the above specific examples. The present invention can provide an optimized solution for the miniaturized, wide-beam scanning array antenna working in the millimeter wave frequency band, and is not limited to the limitations of the unit spacing and the number of units in this embodiment. The technical effect of the present invention can be achieved by the feeding mode of the coupled short-circuit patch antenna unit, or by adjusting the array configuration and polarization characteristics. All technical deformations made according to the technical solutions of the present invention fall within the scope of protection of the present invention.

Claims (10)

1. A wide-angle scanning millimeter-wave array antenna structure is characterized in that it includes a plurality of antenna units arranged at intervals and connected, and the antenna unit includes a first dielectric layer, an adhesive layer and a layer arranged in sequence from top to bottom. The second dielectric layer is provided with a radiation patch layer on the top surface of the first dielectric layer, and the second dielectric layer is provided with a coupling short-circuit structure and a coupling feeding structure symmetrical about the center. 2. A wide-angle scanning millimeter-wave array antenna structure according to claim 1, wherein the top surface of the second dielectric layer is respectively provided with a coupling short-circuit patch layer and a coupling feed patch layer, so that The bottom surface of the second dielectric layer is a metal ground layer. 3. A wide-angle scanning millimeter-wave array antenna structure according to claim 2, wherein the coupling short-circuit patch layer and the coupling feed patch layer are connected to the metal ground layer respectively to form a coupling Short circuit structure, coupled feed structure. 4 . The wide-angle scanning millimeter-wave array antenna structure according to claim 3 , wherein the coupling short-circuit patch layer is connected to the metal ground layer through a short-circuit post. 5 . The wide-angle scanning millimeter-wave array antenna structure according to claim 3 , wherein the coupling and feeding patch layer is connected to the metal ground layer through probes. 6 . The wide-angle scanning millimeter-wave array antenna structure according to claim 5 , wherein the top end and the bottom end of the probe penetrate through the coupling feed patch layer and the metal ground layer respectively. 7 . 7. The wide-angle scanning millimeter-wave array antenna structure according to any one of claims 1-6, wherein the antenna elements are sequentially connected by an antisymmetric neutral line. 8 . The wide-angle scanning millimeter-wave array antenna structure according to claim 7 , wherein both ends of the neutral line are respectively connected to the radiation patch layers of two adjacent antenna units. 9 . The wide-angle scanning millimeter-wave array antenna structure according to any one of claims 1 to 6 , wherein the center-to-center spacing between the antenna elements is ≥0.3 wavelengths. 10 . The wide-angle scanning millimeter-wave array antenna structure according to any one of claims 1 to 6 , wherein the number of the antenna elements is ≥4. 11 .

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