A wide-angle scanning millimeter wave array antenna structure

Abstract

The application relates to a wide-angle scanning millimeter wave array antenna structure, which comprises a plurality of antenna units arranged and connected at intervals, wherein the antenna unit comprises a first dielectric layer, a bonding layer and a second dielectric layer arranged in sequence 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 symmetric about the center, and the antenna units are sequentially connected through anti-symmetrical neutral lines. Compared with the prior art, the coupling short circuit structure is adopted to reduce the vertical current component, thereby reducing the high cross-polarization component of the H plane, improving the radiation characteristics of the antenna unit; the coupling feed form is adopted to further reduce the size of the antenna unit, the spacing between the antenna units is reduced to reduce the sidelobe level when the beam is scanned to a large angle, and the wide-beam scanning capability of the array antenna is expanded; the asymmetric neutral line is used to improve the mutual coupling between the antenna units and reduce the mutual influence between the adjacent antenna units.

Description

Technical Field

[0001] This invention relates to the field of antenna design technology, and in particular to a wide-angle scanning millimeter-wave array antenna structure. Background Technology

[0002] 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 and screens, leaving very limited space for antenna design. Moreover, the orientation of terminal devices during use is arbitrary. To avoid the antenna being blocked and unable to effectively radiate outwards, small-size, wide-angle scanning millimeter-wave array antennas are a major challenge in current terminal antenna design.

[0003] According to the principles of phased arrays, fewer elements and larger element spacing result in a smaller beam scanning range. Common millimeter-wave array antennas (such as the Qualcomm QTM547 millimeter-wave antenna module) are mostly 4-element arrays. The antenna elements need to resonate at 0.5 wavelengths, with an element spacing of 0.5 wavelengths, leading to a larger array size and a limited beam scanning range. To expand the beam scanning range without increasing the number of elements, the element spacing needs to be reduced. For small-pitch array antennas, the challenge lies in how to improve wide beam scanning capability while effectively reducing coupling between antenna elements, while simultaneously miniaturizing the antenna elements.

[0004] To address this, existing technologies for microstrip patch antennas with 0.5-wavelength resonance add a short-circuit wall to ground at the center where the electric field is zero. This does not affect the mode distribution, and the patch size can be reduced to half of the original size, thus realizing a direct short-circuit microstrip patch antenna based on 0.25-wavelength resonance. However, since the short-circuit post introduces a large vertical current component, it generates a high H-plane cross-polarization component, which will affect the radiation characteristics of the antenna element. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by providing a wide-angle scanning millimeter-wave array antenna structure that can optimize the size of the array antenna while effectively improving the radiation characteristics of the antenna elements and reducing the coupling between the antenna elements.

[0006] The objective of this invention can be achieved through the following technical solution: a wide-angle scanning millimeter-wave array antenna structure, comprising multiple antenna elements arranged and connected at intervals, wherein each antenna element comprises a first dielectric layer, an adhesive layer and a second dielectric layer arranged sequentially from top to bottom, the top surface of the first dielectric layer is provided with a radiating patch layer, and the second dielectric layer is provided with a coupling short-circuit structure and a coupling feed structure that are symmetrical about the center.

[0007] Furthermore, the top surface of the second dielectric layer is provided with a coupling short-circuit patch layer and a coupling power supply patch layer, and the bottom surface of the second dielectric layer is a metal ground layer.

[0008] Furthermore, the coupling short-circuit patch layer and the coupling power supply patch layer are respectively connected to the metal ground layer to form a coupling short-circuit structure and a coupling power supply structure.

[0009] Furthermore, the coupling short-circuit patch layer is connected to the metal ground layer via a short-circuit post.

[0010] Furthermore, the coupled power-feed patch layer is connected to the metal ground layer via a probe.

[0011] Furthermore, the top and bottom ends of the probe penetrate the coupling feed patch layer and the metal ground layer, respectively.

[0012] Furthermore, the antenna elements are connected sequentially by antisymmetric neutral lines.

[0013] Furthermore, the two ends of the neutralization line are respectively connected to the radiating patch layers of two adjacent antenna elements.

[0014] Furthermore, the center-to-center spacing between the antenna elements is ≥0.3 wavelengths.

[0015] Furthermore, the number of antenna elements is ≥4.

[0016] Compared with the prior art, the present invention sets a coupled short-circuit structure and a coupled feeding structure in the second dielectric layer of the antenna element. On the one hand, by using the coupled short-circuit structure to replace the traditional direct short-circuit structure, the vertical current component can be effectively reduced, thereby reducing the high cross-polarization component of the H plane and improving the radiation characteristics of the antenna element. On the other hand, by using the coupled feeding structure, the size of the antenna element can be further reduced while realizing coupled feeding.

[0017] This invention connects antisymmetric neutral lines sequentially between adjacent antenna elements to introduce new coupling. The newly introduced coupling cancels out the original coupling, which can effectively reduce the mutual influence of coupling between antenna elements and improve the isolation between closely arranged antenna elements.

[0018] This invention sets the center spacing between antenna elements to ≥0.3 wavelengths and the minimum to 0.3 wavelengths to form a compact array antenna structure. By reducing the spacing between antenna elements, the sidelobe level when the beam is scanned to a large angle can be effectively reduced, thereby expanding the wide beam scanning capability of the array antenna. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the antenna element design process in this invention;

[0020] Figure 2 These are the simulation results of the corresponding reflection coefficients during the antenna element design process in this invention;

[0021] Figure 3 This is the H-plane radiation pattern corresponding to the antenna element design process in this invention;

[0022] Figure 4a and Figure 4b This is a schematic diagram of the top surface structure of the antenna element based on 0.25 wavelength resonance in the embodiment;

[0023] Figure 5 This is a side view of the antenna element based on 0.25 wavelength resonance in the embodiment.

[0024] Figure 6 This is a schematic diagram of the top surface structure of the wide-angle scanning millimeter-wave array antenna in the embodiment;

[0025] Figure 7 This is a side view of the wide-angle scanning millimeter-wave array antenna in the embodiment.

[0026] Figure 8a , 8b Figure 8c is a schematic diagram of the neutral line design process for the wide-angle scanning millimeter-wave array antenna in the embodiment;

[0027] Figure 9a , 9b 9c represents the simulation results of the isolation during the neutral line design process of the wide-angle scanning millimeter-wave array antenna in the embodiment;

[0028] Figure 10a and Figure 10b The simulation results show the radiation patterns of the wide-angle scanning millimeter-wave array antenna under different beams in the embodiment. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0030] Example

[0031] like Figure 5 , 6 As shown in Figure 7, a wide-angle scanning millimeter-wave array antenna structure includes multiple antenna elements arranged and connected at intervals. Each antenna element includes a first dielectric layer, an adhesive layer, and a second dielectric layer arranged sequentially from top to bottom. A radiating patch layer (such as...) is disposed on the top surface of the first dielectric layer. Figure 5 As shown in the antenna patch, the second dielectric layer has a centrally symmetrical coupled short-circuit structure and coupled feed structure.

[0032] Specifically, the top surface of the second dielectric layer is provided with a coupling short-circuit patch layer and a coupling power supply patch layer, and the bottom surface of the second dielectric layer is a metal ground layer. The coupling short-circuit patch layer and the coupling power supply patch layer are connected to the metal ground layer to form a coupling short-circuit structure and a coupling power supply structure, respectively.

[0033] The coupling short-circuit patch layer is connected to the metal ground plane layer via a short-circuit post, while the coupling power-feed patch layer is connected to the metal ground plane layer via a probe. The top and bottom ends of the probe penetrate the coupling power-feed patch layer and the metal ground plane layer, respectively.

[0034] Furthermore, the antenna elements are connected sequentially via antisymmetric neutral lines (e.g. Figure 6 As shown in the figure, the two ends of the neutralization line are connected to the radiating patch layers of the two adjacent antenna elements, respectively.

[0035] 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-to-center spacing between antenna elements is designed to be 0.3 wavelengths, and four antenna elements are linearly connected in a wiring array to form an array antenna structure, which can cover the 25.5-27.5 GHz millimeter wave band.

[0036] Figure 1 The diagram illustrates the antenna element design process in this invention, where the antenna element evolves from a conventional patch antenna based on a 0.5-wavelength resonant. In existing technologies, for a conventional patch antenna operating in TM01 mode, the electric field at the center of symmetry is zero. Adding a short-circuit wall to ground will not affect the mode distribution of the patch antenna, and the size of the patch antenna can be reduced to half its original size. However, the direct short-circuit structure introduces a large vertical current component, resulting in a high cross-polarization component in the H-plane for the direct short-circuit patch antenna based on a 0.25-wavelength resonant. Therefore, 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.

[0037] Figure 2 The diagram shows the simulation structure of the corresponding reflection coefficient during the antenna element design process in this invention. The ordinary patch antenna based on 0.5 wavelength resonance, the direct short-circuit patch antenna based on 0.25 wavelength resonance, and the coupled short-circuit patch antenna based on 0.25 wavelength resonance (i.e., using this technical solution) are all tuned to the 25.5-27.5 GHz frequency band. Figure 2 It can be seen that this technical solution can effectively reduce the high cross-polarization component of the H-plane.

[0038] Figure 3The diagram shows the H-plane radiation pattern corresponding to the antenna element design process in this invention. The H-plane peak gain and cross-polarization level of a conventional patch antenna are 7.7 dBi and -17 dB, respectively. The direct short-circuit patch antenna, due to increased asymmetry causing pattern deflection, has an H-plane peak gain of only 2.7 dBi, and the H-plane cross-polarization level is as high as -2.2 dB due to the vertical current component introduced by the short-circuit post. In contrast, the coupled short-circuit patch antenna designed in this invention significantly reduces the asymmetry of the short-circuit patch and decreases the vertical current component, achieving an H-plane peak gain of 6.3 dBi and a cross-polarization level of -12.4 dB, representing a significant improvement.

[0039] Figure 4a , 4b and Figure 5 The figures show the top and side structures of the coupled short-circuit patch antenna based on 0.25 wavelength resonance in this embodiment. The dimensions of each part in the figures are as follows: 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, all in mm.

[0040] Figure 6 and Figure 7 The figures show the top and side structures of the wide-angle scanning millimeter-wave array antenna in this embodiment. The dimensions of each part in the figures are: D = 3.4, La = 12.9, Wa = 5, all in mm.

[0041] Therefore, the array antenna designed in this embodiment consists of four patch antenna elements, arranged linearly with a center-to-center spacing of 0.3 wavelengths to form the array antenna. Each antenna element is composed of three dielectric substrate layers: antenna dielectric layer 1, adhesive layer, and antenna dielectric layer 2, from top to bottom. The radiating patch layer is located on the top surface of antenna dielectric layer 1, while the coupling short-circuit patch layer and coupling feed patch layer are both located on the top surface of antenna dielectric layer 2. The bottom surface of antenna dielectric layer 2 is a metal ground plane. Antenna dielectric layer 1 and antenna dielectric layer 2 are bonded together by the adhesive layer. Each antenna element is fed by a probe that penetrates the metal ground plane and antenna dielectric layer 2, combined with a coupling feed patch disposed on the surface of antenna dielectric layer 2. The coupling short-circuit structure is formed by a short-circuit post connecting the coupling short-circuit patch located on the surface of antenna dielectric layer 2 and the metal ground plane. In the radiating patch layer, adjacent radiating patches are connected by anti-symmetric neutral lines to improve the isolation between the closely arranged antenna elements.

[0042] Figure 8a , 8bFigures 8 and 8c illustrate the neutralization 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 conventionally connected neutralization lines on the same side is limited. Therefore, this technical solution adopts an antisymmetric neutralization line structure to improve the isolation between antennas.

[0043] Figure 9a , 9b Figures 9c show the simulation results of the isolation during the neutral line design process of the wide-angle scanning millimeter-wave array antenna in this embodiment. Without neutral line decoupling, the coupling between adjacent antenna elements is as high as -8.9dB, and the mutual influence between antennas is large, resulting in the deterioration of the radiation pattern, resonance and other characteristics of the array antenna. When using the same-side neutral line decoupling, the antenna isolation is improved, but the mutual coupling between the middle antenna elements 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 antenna elements, making the isolation between adjacent antenna elements in the array better than 14.5dB. In other words, this technical solution introduces new coupling between closely placed adjacent antenna elements using an asymmetric neutralization line. By controlling the size of the patch antenna, the original coupling is changed, and the dimensions of both are adjusted so that the newly introduced coupling cancels out the original coupling. (In actual design applications, the length and height of the neutralization line can be directly adjusted, while the size of the antenna radiating patch is adjusted in conjunction with the position movement of the coupling short-circuit structure to ensure that the operating frequency band of the antenna element remains unchanged.) This can improve the mutual coupling between antenna elements from -8.9dB when there is no neutralization line for decoupling to below -15dB.

[0044] Figure 10a , 10b The figure shown is a simulation diagram of the radiation direction of the wide-angle scanning millimeter-wave array antenna in this embodiment under different beam directions. It can be seen that in the beam scanning range of -60° to 60°, the peak gain fluctuation is only 1.6dB, the sidelobe voltage is better than -7.7dB, and the cross-polarization isolation is greater than 12dB. The array has good gain, low sidelobe level and low cross-polarization level.

[0045] In summary, the wide-angle scanning millimeter-wave array antenna in this embodiment is based on a miniaturized 0.25-wavelength resonant coupled short-circuit patch antenna design. First, a coupled short-circuit structure is used instead of a direct short circuit to reduce the high cross-polarization component of the H-plane of the patch antenna based on the 0.25-wavelength resonant.

[0046] Secondly, to reduce the array size and expand the beam scanning range, the array antenna is arranged with an element spacing of 0.3 wavelengths. This can effectively reduce the sidelobe level when the beam is scanned to a large angle and achieve wide-angle scanning. However, due to the close arrangement of the antenna elements, the mutual influence increases, which will lead to the deterioration of the resonance and radiation characteristics of the antenna elements. Therefore, an antisymmetric neutral line structure is designed to reduce the mutual coupling between antenna elements, improve the isolation between antenna elements, and ensure the array characteristics. As a result, the millimeter-wave array antenna proposed in this technical solution has a significant improvement in antenna size, beam scanning range, and decoupling performance.

[0047] It should be noted that the center-to-center spacing between the antenna elements in this embodiment is 0.3 wavelengths, which is a very small value. Decoupling is very difficult with such a small element spacing. This technical solution designs an antisymmetric neutralization line to connect the antenna elements, which can effectively decouple them. For the element spacing greater than 0.3 wavelengths, the decoupling difficulty decreases accordingly, and the antisymmetric neutralization line decoupling proposed in this technical solution is also more applicable. In addition, in order to adapt to the application requirements of mobile terminals for small-sized millimeter-wave antennas, this embodiment only uses 4 antenna elements, but the application of this technical solution can be extended to cases with more than 4 antenna elements.

[0048] The technical solution of this invention is not limited to the specific examples described above. This invention can provide an optimized solution for miniaturized, wide-beam scanning array antennas operating in the millimeter-wave band. It is not limited to the element spacing or number of elements in this embodiment. Adjusting the feeding method of the coupled short-circuit patch antenna elements, or adjusting the array configuration and polarization characteristics, can all achieve the technical effects of this invention. All technical modifications made according to the technical solution of this invention fall within the protection scope of this invention.

Claims

1. A wide-angle scanning millimeter-wave array antenna structure, characterized in that, The antenna includes multiple antenna elements arranged and connected at intervals. Each antenna element includes a first dielectric layer, an adhesive layer, and a second dielectric layer arranged sequentially from top to bottom. A radiating patch layer is provided on the top surface of the first dielectric layer. The second dielectric layer is provided with a coupling short-circuit structure and a coupling feed structure. Both the coupling short-circuit structure and the coupling feed structure are centrally symmetrical structures. The center-to-center spacing between the antenna elements is ≥0.3 wavelengths. The antenna elements are connected sequentially by anti-symmetric neutralization lines. The two ends of the neutralization lines are respectively connected to the radiating patch layers of two adjacent antenna elements. The top surface of the second dielectric layer is provided with a coupling short-circuit patch layer and a coupling power supply patch layer, and the bottom surface of the second dielectric layer is a metal ground layer; The coupling short-circuit patch layer and the coupling power supply patch layer are respectively connected to the metal ground layer to form a coupling short-circuit structure and a coupling power supply structure. The coupling short-circuit patch layer is connected to the metal ground layer via a short-circuit post.

2. The wide-angle scanning millimeter-wave array antenna structure according to claim 1, characterized in that, The coupled power-feed patch layer is connected to the metal ground layer via a probe.

3. The wide-angle scanning millimeter-wave array antenna structure according to claim 2, characterized in that, The top and bottom ends of the probe penetrate the coupling feed patch layer and the metal ground layer, respectively.

4. A wide-angle scanning millimeter-wave array antenna structure according to any one of claims 1 to 3, characterized in that, The number of antenna elements is ≥4.

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