A novel millimeter wave array planar decoupling antenna

Abstract

The application provides a novel millimeter wave array plane decoupling antenna, UV branches are printed between any two string feed patch antennas by etching the UV branches on the upper surface of a dielectric substrate, so that the phase of surface waves propagating through the UV branches is changed by 180 degrees from the phase of space waves, and the coupling of space waves is cancelled, so that the influence of antenna mutual coupling is reduced, and the isolation is improved. The UV branches are further arranged at the upper and lower sides of each patch to form a structure similar to a parasitic unit, so that the bandwidth can be expanded, and the high gain of the antenna is considered.

Description

Technical Field

[0001] This invention relates to the field of vehicle-mounted antenna technology, and in particular to a novel millimeter-wave array planar decoupled antenna. Background Technology

[0002] Currently, due to various limitations in the size and manufacturing process of millimeter-wave radar, only planar structures can be used to improve the performance of millimeter-wave arrays, meaning they can only be printed on the antenna substrate along with the antenna. This also means that many techniques used in low-frequency antennas, such as those in the microwave band, cannot be used in millimeter-wave radar arrays.

[0003] Among the existing mature solutions for enhancing the isolation of millimeter-wave arrays, the Mushroom-type EBG structure and the dummy antenna scheme are the most commonly used. The Mushroom-type EBG structure, by employing equivalent capacitance and inductance, can act like a filter, blocking plane wave coupling within a specific frequency range. However, due to the small array spacing and the periodic nature of the EBG structure, the distance between the array and the antenna is too small, significantly reducing the antenna's bandwidth and scanning angle. The dummy antenna scheme, on the other hand, involves inserting a dummy antenna identical to the array antennas between them. This additional dummy antenna introduces additional coupling, and by properly adjusting the feed lines and lumped element loads at the dummy antenna ports, the phase and amplitude of the dummy antenna reflection can be adjusted, achieving a mutual cancellation effect with the original coupling, thus enhancing the array's isolation. Furthermore, this scheme effectively expands the antenna's radiation pattern bandwidth while simultaneously improving isolation. However, it also has significant drawbacks: First, it requires the use of lumped elements, which increases costs; second, while increasing the beamwidth, it significantly reduces the maximum gain, and this cannot be improved by adjusting the dummy antenna; third, the improvement in isolation is limited, the length of the dummy antenna feed line and the resistance of the load lumped element require complex calculations, and the relevant resistor values ​​may not be readily available. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a novel millimeter-wave array planar decoupled antenna, comprising at least: UV stubs etched on the upper surface of a dielectric substrate, wherein the UV stubs are printed between any two feed patch antennas, the UV stubs are arranged in two columns in an alternating asymmetrical distribution, and the UV stubs are U-shaped.

[0005] The UV branch includes a first vertical segment and a second vertical segment distributed on the left and right sides, a horizontal segment distributed in the middle, and a first oblique segment and a second oblique segment that connect the two ends of the horizontal segment to the first vertical segment and the second vertical segment, respectively.

[0006] The series-fed patch antenna consists of at least two columns of antennas of the same type. The series-fed patch antenna is composed of patch radiating elements that gradually decrease in size from the middle to both sides. The patch radiating elements are connected by feed lines and are distributed crosswise on the left and right sides of the feed lines.

[0007] The UV stubs are arranged in two columns at the middle position of each of the two columns of the series-fed patch antenna, and are distributed correspondingly to the patch radiating elements on one side of the series-fed patch antenna.

[0008] The UV branches are distributed in pairs on both sides of the patch radiation unit with the horizontal central axis of the patch radiation unit as the axis of symmetry.

[0009] Furthermore, each pair of UV branches faces away from each other and their openings face both sides of the horizontal central axis of the patch radiation unit.

[0010] Furthermore, the spacing between each pair of UV stubs is wider than the width of its corresponding patch radiating unit by a preset value. The stubs are coupled through the horizontal segment and the patch radiating unit of the antenna. The coupled signal is coupled to the first vertical segment of the adjacent UV stub through the second vertical segment, and the coupling is continuously transmitted until it is transmitted to another antenna.

[0011] The column spacing between the two UV stubs is a preset distance; the spacing between the UV stubs and the series-fed patch antenna is another preset distance.

[0012] No UV stubs are provided at the patch radiating elements at both ends of the series-fed patch antenna.

[0013] The total length of the UV branch is equal to half the wavelength at the center frequency.

[0014] In summary, this invention provides a novel millimeter-wave array planar decoupled antenna. By etching UV stubs onto the upper surface of a dielectric substrate and printing these stubs between any two feed patch antennas, the phase of the surface wave propagating directly through the UV rays is altered, resulting in a 180° phase difference with the space wave. This cancels out the coupling with the space wave, reducing the overall mutual coupling of the antenna and thus improving isolation. Furthermore, by placing the UV stubs on both sides above each feed patch, a parasitic element-like structure is formed, which can extend the beamwidth while maintaining high antenna gain. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a novel millimeter-wave array planar decoupled antenna according to the present invention.

[0016] Figure 2 for Figure 1 A schematic diagram of the UV branch described in the document.

[0017] Figure 3 for Figure 1 The simulation results of the S-parameters of the millimeter-wave array antenna are shown in the figure.

[0018] Figure 4 for Figure 1 The diagram shows the improvement in beamwidth at 6dB power for the millimeter-wave array antenna.

[0019] Figure 5 for Figure 1 The diagram shows the improvement in beamwidth at 10dB power for the millimeter-wave array antenna.

[0020] Figure 6 for Figure 1 The maximum gain effect diagram of the millimeter-wave array antenna.

[0021] Wherein, 1-dielectric substrate; 2-feed patch antenna; 3-UV stub; 31-first vertical segment; 32-second vertical segment; 33-first oblique segment; 34-second oblique segment; 35-horizontal segment. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figure 1 As shown, this invention proposes a novel millimeter-wave array planar decoupling antenna. The overall effect is illustrated in the diagram. UV stubs are arranged in an alternating asymmetrical pattern between two strings of feed patch antennas, without any connection. Specifically, the novel millimeter-wave array planar decoupling antenna of this invention includes: UV stubs etched onto the upper surface of a dielectric substrate. These UV stubs are printed between any two strings of feed patch antennas. The UV stubs are arranged in two alternating asymmetrical columns, and are U-shaped. Figure 2 As shown, the coupling between patch antennas is mainly divided into two types: spatial wave coupling and surface wave coupling. The UV stub mentioned in this scheme uses the change of the phase of surface wave coupling to change the phase of the surface wave after direct propagation through UV, so that the phase of the surface wave is 180° different from the phase of the spatial wave, thus canceling the coupling with the spatial wave, thereby reducing the influence of the overall mutual coupling of the antenna and improving the isolation.

[0024] Specifically, the structure in this design directly prints or etches the decoupling structure onto the dielectric substrate, eliminating the need for vias and external lumped resistors, thus simplifying the process. The antenna decoupling mechanism designed in this invention is as follows: the antenna is a comb-type series-fed array antenna, with UV stubs symmetrically placed on both sides of the antenna radiating element. The UV stubs are coupled to the antenna radiating element via horizontal segments. Since the total length of the UV stubs is half a wavelength, the coupled signal can be transmitted relatively efficiently on this structure. The coupled signal is then coupled through the vertical segments of the UV stubs to the vertical segments of another adjacent UV stub, and then similarly coupled through the horizontal segments to the radiating element of the second antenna. This alters the original propagation path of the surface wave, and by rationally adjusting the phase of the surface wave coupling, it achieves anti-cancellation with the space wave coupling.

[0025] Preferably, the antenna of the present invention includes at least: UV stubs etched on the upper surface of a dielectric substrate, the UV stubs being printed between any two feed patch antennas, the UV stubs being distributed in two staggered and asymmetrical columns, and the UV stubs being U-shaped.

[0026] The UV branch includes a first vertical segment and a second vertical segment distributed on the left and right sides, a horizontal segment distributed in the middle, and a first oblique segment and a second oblique segment that connect the two ends of the horizontal segment to the first vertical segment and the second vertical segment, respectively.

[0027] The series-fed patch antenna consists of at least two columns of antennas of the same type. The series-fed patch antenna is composed of patch radiating elements that gradually decrease in size from the middle to both sides. The patch radiating elements are connected by feed lines and are distributed crosswise on the left and right sides of the feed lines.

[0028] The UV stubs are arranged in two rows at the midpoint of each pair of series-fed patch antennas, corresponding to the patch radiating elements on one side of the series-fed patch antennas. Because the UV stubs are positioned between the two antennas and are close to the antenna spacing, they act as parasitic elements of the antennas, thereby expanding the antenna beamwidth. By adjusting the spacing between the UV stubs and the antennas, the beamwidth and radiation gain can be adjusted.

[0029] The UV branches are distributed in pairs on both sides of the patch radiation unit with the horizontal central axis of the patch radiation unit as the axis of symmetry.

[0030] Furthermore, each pair of UV branches faces away from each other and their openings face both sides of the horizontal central axis of the patch radiation unit.

[0031] Furthermore, the spacing between each pair of UV stubs is wider than the width of its corresponding patch radiating unit by a preset value. The stubs are coupled through the horizontal segment and the patch radiating unit of the antenna. The coupled signal is coupled to the first vertical segment of the adjacent UV stub through the second vertical segment, and the coupling is continuously transmitted until it is transmitted to another antenna.

[0032] The column spacing between the two UV stubs is a preset distance; the spacing between the UV stubs and the series-fed patch antenna is another preset distance.

[0033] No UV stubs are provided at the patch radiating elements at both ends of the series-fed patch antenna.

[0034] The total length of the UV branch is equal to half the wavelength at the center frequency.

[0035] In summary, this invention, by printing UV stubs between any two feed patch antennas, i.e., on both sides above each feed patch, eliminates the need for external lumped resistors and vias on the dielectric substrate, simplifying the process. It achieves a maximum isolation improvement of 14dB, with at least 35dB isolation across the operating frequency band. Furthermore, while achieving this isolation, it has minimal impact on antenna return loss (impedance matching), requiring no additional antenna adjustments for matching. The 6dB power bandwidth is increased from approximately 105° to approximately 120°. While maintaining the required bandwidth, the maximum gain is kept at approximately 14dBi by suppressing the radiation pattern. Specifically, to further illustrate the effectiveness of the antenna design, a simulation of the novel millimeter-wave array planar decoupled antenna described in this invention is performed, wherein:

[0036] Figure 3 The image shows a simulation of the isolation performance of the millimeter-wave array antenna described in this invention. It can be seen that the improved millimeter-wave array antenna can effectively improve the isolation performance.

[0037] Figures 4-5 The figures show the improvement in beamwidth at 6dB and 10dB power for the millimeter-wave array antenna described in this invention. Compared to before the improvement, the millimeter-wave array antenna described in this invention can effectively improve the beamwidth.

[0038] Figure 6 The diagram shows the maximum gain of the millimeter-wave array antenna. Although the overall gain remains above 14 dBi, the maximum gain is slightly reduced while maintaining the required bandwidth.

[0039] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A novel millimeter wave array planar decoupling antenna, characterized in that, At least comprising: UV branches etched on the upper surface of the dielectric substrate, the UV branches are printed between any two series of feed patch antennas, the UV branches are in staggered asymmetric distribution, the UV branches are U-shaped; The UV branches are arranged in 2 columns at the middle position of every 2 columns of the series of feed patch antennas, and are distributed corresponding to the patch radiation units on one side of the series of feed patch antennas; The UV branches are arranged in pairs on both sides of the patch radiation units with the horizontal central axis of the patch radiation units as the symmetric axis; Each pair of UV branches is opposite to each other and opens towards both sides of the horizontal central axis of the patch radiation units; The series of feed patch antennas are at least 2 columns of antennas of the same type, the series of feed patch antennas are composed of patch radiation units gradually from large to small from the middle to both sides, the patch radiation units are connected by feed lines, and the patch radiation units are cross-distributed on both sides of the feed lines.

2. The novel millimeter wave array planar decoupling antenna according to claim 1, characterized in that, The UV branches include first and second vertical segments respectively distributed on the left and right sides, a horizontal segment distributed in the middle, and first and second diagonal segments respectively connecting the two ends of the horizontal segment to the first and second vertical segments.

3. The novel millimeter-wave array planar decoupling antenna according to claim 2, characterized in that, The distance between the two UV branches inside each pair of UV branches is wider than the width of the corresponding patch radiation unit by a predetermined value, The horizontal segment and the patch radiation unit of the antenna are coupled, the coupled signal is coupled to the first vertical segment of the adjacent UV branch through the second vertical segment, and the coupling is continuously transmitted until another antenna is transmitted.

4. The novel millimeter-wave array planar decoupling antenna according to claim 3, characterized in that, The column spacing of the two columns of UV branches is a predetermined distance; the spacing between the UV branches and the series of feed patch antennas is another predetermined distance.

5. The novel millimeter-wave array planar decoupling antenna according to claim 4, characterized in that, No UV branch is arranged at the patch radiation unit at the head and tail of the series of feed patch antennas.

6. The novel millimeter-wave array planar decoupling antenna according to claim 5, characterized in that, The total length of the UV branch is equal to half the wavelength length at the center frequency.

Images