WO2023000462A1 - 一种低仰角增益增强的宽角双圆极化天线及设备 - Google Patents

一种低仰角增益增强的宽角双圆极化天线及设备 Download PDF

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Publication number
WO2023000462A1
WO2023000462A1 PCT/CN2021/117250 CN2021117250W WO2023000462A1 WO 2023000462 A1 WO2023000462 A1 WO 2023000462A1 CN 2021117250 W CN2021117250 W CN 2021117250W WO 2023000462 A1 WO2023000462 A1 WO 2023000462A1
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dielectric substrate
shaped
circularly polarized
inverted
wide
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PCT/CN2021/117250
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English (en)
French (fr)
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曲培树
董文会
刘金海
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德州学院
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Publication of WO2023000462A1 publication Critical patent/WO2023000462A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
    • H01Q9/0428—Substantially flat resonant element parallel to ground plane, e.g. patch antenna radiating a circular polarised wave
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/002—Protection against seismic waves, thermal radiation or other disturbances, e.g. nuclear explosion; Arrangements for improving the power handling capability of an antenna
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
    • H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/50—Feeding or matching arrangements for broad-band or multi-band operation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
    • H01Q9/045—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with particular feeding means
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Definitions

  • the invention belongs to the field of wireless communication, in particular to a wide-angle double-circularly polarized antenna and equipment with enhanced gain at low elevation angles.
  • the antenna is an important part of wireless communication, radar and other systems, and the performance of the antenna directly affects the performance of the entire system to a large extent.
  • the poor gain at low elevation angles of the antenna will directly affect the performance of communication systems such as aviation, satellite communication, radar, remote control and telemetry.
  • the satellite signal covers the marginal area and the aircraft is in an unstable attitude such as roll or pitch, it will also cause the problem of signal connection interruption.
  • Circularly polarized antennas have many advantages over linearly polarized antennas: they have advantages in anti-interference, anti-fading, and anti-multipath effects; they are orthogonal to the direction of rotation; they receive incoming waves with any polarization, and their radiated waves can also be transmitted by any polarization antenna.
  • Reception When the circularly polarized wave is incident on a symmetrical target, the direction of the reflected wave is reversed. This feature is used in the field of GPS and mobile communications to resist rain and fog interference and multipath reflection.
  • the antenna is required to have circular polarization and sufficiently large gain characteristics at low elevation angles to effectively capture weak signals at low elevation angles.
  • due to the need to track and measure high-speed targets under various polarization modes and climatic conditions it is difficult for a single polarization mode to meet the above-mentioned application requirements.
  • this type The antenna polarization is still a single-polarization working mode, and the loss of the antenna is large, which seriously affects the signal-to-noise ratio quality of the communication process.
  • the present invention provides a wide-angle dual circularly polarized antenna and equipment with low transmission loss and low elevation gain enhancement, which has simple structure, low cost, low loss and low elevation gain Advanced advantages.
  • the first aspect of the present invention provides a low-elevation-angle gain-enhanced wide-angle dual-circularly polarized antenna, which includes a cutout wall, a C-shaped feed network, a lower dielectric substrate, an upper dielectric substrate, an inverted U-shaped feed structure, and a metal radiation SMD and a pair of coaxial adapters;
  • the cutout wall is arranged around the lower dielectric substrate, and the C-shaped feed network is arranged on the upper surface of the lower dielectric substrate; the C-shaped feed network is provided with several feed branches and several comb-shaped artificial surface plasmon excitations.
  • a meta structure, the feed branch is connected to the feed end of the inverted U-shaped feed structure; the inverted U-shaped feed structure is arranged between the C-shaped feed network and the metal radiation patch; the metal radiation patch It is arranged on the upper side of the inverted U-shaped feed structure and laid on the upper surface of the upper dielectric substrate; a pair of coaxial conversion joints are arranged at the end of the C-shaped feed network and located under the lower dielectric substrate.
  • the height of the notch wall determines the gain level of the dual circularly polarized antenna at a low elevation angle.
  • the cutout wall includes several metal sheets, and these metal sheets are evenly distributed along the circumference with a set radius around the center of the lower dielectric substrate.
  • the dielectric constant of the lower dielectric substrate is the same as that of the upper dielectric substrate.
  • the lower surface of the lower dielectric substrate is entirely covered with a conductive medium.
  • the inner side of the structure of the C-type feeding network is etched with several evenly distributed comb-shaped artificial surface plasmon structures, and the outer side of the structure of the C-type feeding network is derived from several uniformly distributed feeding branches .
  • the inverted U-shaped feed structure includes several identical inverted U-shaped structures, which are evenly distributed in a rotational manner along the circumferential direction with a set radius.
  • each inverted U-shaped structure is provided with a feed end and a short-circuit end, and the short-circuit end is short-circuit connected to the conductive medium on the lower surface of the lower dielectric substrate.
  • the metal radiation patch includes several fan-shaped metal patches extending outward from the center, and the distance between adjacent fan-shaped radiation patches is equal.
  • the lower dielectric substrate is disposed on a metal bottom plate.
  • a second aspect of the present invention provides a device comprising the wide-angle dual circularly polarized antenna with enhanced gain at low elevation angles as described above.
  • the present invention introduces an inverted U-shaped feed structure and a metal radiation patch, so that the cross-sectional height of the antenna is less than 0.2 ⁇ 0 ( ⁇ 0 is the wavelength for the center frequency);
  • the invention introduces the artificial surface plasmon technology, effectively reduces the transmission loss of the microwave network, improves the radiation gain of the antenna and the signal-to-noise ratio of the communication system, and effectively improves the communication quality of the system.
  • the present invention adopts the technology of combining dual-port feed and multi-feed points, firstly, the N feeds of the antenna are evenly distributed on the circle with a radius of D, and the symmetry of the antenna is improved through the multi-feed point technology, thereby realizing The stability design of the antenna phase center; secondly, the dual-port technology is used to feed the antenna, which realizes the free switching of the left-handed and right-handed polarization working modes of the antenna;
  • the invention introduces the notched wall technology, which effectively improves the gain at the low elevation angle of the antenna, realizes the wide beam design of the antenna, and improves the radiation pattern of the antenna.
  • Fig. 1 (a) is single-feed method perturbation mode embodiment 1 of the present invention
  • Fig. 1 (b) is single-feed method perturbation mode embodiment 2 of the present invention
  • Fig. 1 (c) is single-feed method perturbation mode embodiment 3 of the present invention.
  • FIG. 2 is a perspective view of a wide-angle dual circularly polarized antenna with enhanced gain at low elevation angles according to an embodiment of the present invention
  • Fig. 3 is a C-type feed network structure diagram of the antenna of the embodiment of the present invention.
  • Fig. 4 is a structural diagram of a metal radiation patch of an antenna according to an embodiment of the present invention.
  • Fig. 6 is a structural diagram of a notch wall of the antenna of the embodiment of the present invention.
  • Fig. 8 is a right-hand circularly polarized far-field pattern at the center frequency of the antenna according to the embodiment of the present invention.
  • 100 metal bottom plate; 101, notch wall; 102, lower dielectric substrate; 103, inverted U-shaped feed installation hole; 104, coaxial conversion joint installation hole; 201, C-type feed network; 202, C-type 203, the second end of the C-type feed network; 204, the feed branch; 205, the comb-shaped artificial surface plasmon; 206, the ground conductor plane; 300, the upper dielectric substrate; 301, the inverted U-shaped feed structure; 302, metal radiation patch; 303, short circuit end; 304, feed end; 401, first coaxial conversion joint; 402, second coaxial conversion joint.
  • circularly polarized antennas are more widely used than linearly polarized antennas, and are one of the important topics in antenna theory.
  • There are many methods for antennas to achieve circular polarization such as the single-point feed method and the multi-point orthogonal feed method that add perturbation to a single antenna, and the multi-element method composed of multiple antennas and feed networks. These are A common method for antennas to achieve circularly polarized radiation.
  • the design of the single-feed method can be analyzed with the cavity model theory, which utilizes the merger mode of two radiating orthogonal polarizations to realize circular polarization.
  • the resonant frequencies of the two orthogonal modes are separated by means of perturbation on the antenna, and the 90° phase angle of the equivalent impedance of the two merged modes is used.
  • Degree phase difference 45 degrees ahead/45 degrees behind effect, forming circularly polarized radiation in the far field area.
  • the single-feed method is favored by many engineers because of its simple structure, low cost, and no need for an external feed network.
  • the circularly polarized antenna of the single-feed method there are disadvantages such as narrow operating bandwidth, poor polarization characteristics, and low gain at low elevation angles.
  • multi-feed method and multi-element method are usually used.
  • this embodiment adopts the feed technology combining artificial surface plasmons and multiple feed points, not only obtaining a microwave network with low loss characteristics, but also realizing the dual circular polarization of the antenna.
  • the gain at low elevation angle of the antenna is further improved, and the wide beam working characteristics of the antenna are realized.
  • the wide-angle dual circularly polarized antenna that the low-elevation angle gain that the present embodiment forms is enhanced utilizes radius to be Ro, and the notch wall that height is Hg forms concave ring structure cavity, and antenna unit height is H, and antenna is with The origin is the center of the circle, and the radius is Ri, and the circumferential rotation forms the antenna of the example of the present invention.
  • a wide-angle dual circularly polarized antenna with enhanced gain at low elevation angles in this embodiment includes a cutout wall 101, a C-shaped feed network 201, a lower dielectric substrate 102, an upper dielectric substrate 300, and an inverted U-shaped feed network.
  • the pair of coaxial conversion joints are respectively a first coaxial conversion joint 401 and a second coaxial conversion joint 402 .
  • the cutout wall 101 is arranged around the lower dielectric substrate 102.
  • the feeding branch 204 and the artificial surface plasmon 205 the feeding branch 204 is connected to the feeding end 304 of the inverted U-shaped feeding structure 301; the inverted U-shaped feeding structure 301 is set in the C-shaped feeding network 201 and the metal radiation patch 302; the metal radiation patch 302 is set on the upper side of the inverted U-shaped feed structure 301 and laid on the upper surface of the upper dielectric substrate 300; a pair of coaxial conversion joints are set on the C-shaped The end of the feeding network is located below the lower dielectric substrate.
  • the artificial surface plasmon 205 is arranged inside the C-type feeding network.
  • the artificial surface plasmons arranged at the ports 202 and 203 form a low-to-high transmission transition section (heights h1, h2, h3...hn) from the outside to the inside, and are set in the C-type feed network
  • the comb-shaped artificial surface plasmon structure of the main part is composed of several uniformly distributed comb-like structures with equal height (Hp) and width (wp).
  • the ground conductor plane 206 is connected to the metal coating section on the lower surface of the dielectric layer through the metal short-circuit column.
  • the dielectric constant of the lower dielectric substrate 102 is the same as that of the upper dielectric substrate 300 .
  • the lower surface of the lower dielectric substrate 102 is entirely covered with a conductive medium, such as copper.
  • the dielectric constant of the lower dielectric substrate 102 is 2.65, the thickness is T1, and the radius is F4B plate material Ro.
  • the lower surface of the lower dielectric substrate is entirely covered with copper, and the upper surface is printed with a C-type feed network 201 .
  • the upper dielectric substrate 300 is an F4B plate with a dielectric constant of 2.65, a thickness of T2, and a radius of Ri, and its upper surface is covered with a metal radiation patch 302 .
  • the notch wall 101 is made of metal.
  • the cutout wall 101 includes several metal sheets, which are centered at the center of the lower dielectric substrate and evenly distributed along the circumference with a set radius.
  • the notch wall 101 is composed of N metal sheets with a width of Wg and a height of Hg, which are evenly distributed along the circumferential direction with the center of the overall structure as the center and with a radius of Ro.
  • the notch wall 101 is centered on the origin, and the number is N, and rotates along the circumferential direction to form a single-layer thin-walled concave barrel structure, and is fixed above the lower dielectric substrate 102, and is short-circuited with the metal-clad copper on the lower surface of the lower dielectric substrate 102 connected to form a single-layer thin-walled concave disk-shaped structure;
  • the lower dielectric substrate 102 has a circular structure, the lower surface of which is covered with metal copper, and the upper surface is printed with a C-shaped feed network 201 .
  • the C-shaped feed network 201 is arranged on the upper surface of the lower dielectric substrate 102, and N feed stubs 204 are connected to its structural abdomen, forming branch terminals distributed in a star structure.
  • the end of the feed network of the C-type feed network 201 is connected to the inner core of the coaxial conversion joint passing through the coaxial conversion joint installation hole 104.
  • the N comb-shaped concave-convex structures evenly distributed inside the C-type feed network constitute the artificial surface plasmon 205 for low-loss transmission;
  • the coaxial conversion joint is arranged under the lower dielectric substrate 102, Its outer conductor is connected to the metal clad copper on the lower surface of the lower dielectric substrate 102;
  • the inverted U-shaped feed structure includes several identical inverted U-shaped structures, and these inverted U-shaped structures are uniformly distributed in a rotational manner along the circumferential direction with a set radius.
  • the inverted U-shaped feeding structure 301 is arranged on the top of the lower dielectric substrate 102, and the number is N.
  • the inverted U-shaped structure feeding end 304 is installed in the inverted U-shaped feeding installation hole 103 and connected to the feeding network branch 204.
  • the short-circuit end 303 of its inverted U-shaped structure is short-circuited with the metal-clad copper on the lower surface of the lower dielectric substrate 102;
  • the metal radiation patch 302 is arranged on the upper part of the inverted U-shaped feed structure 301, printed on the upper surface of the upper dielectric substrate 300, and is made of N fan-shaped structures that gradually widen from the center to the edge. and the arc part of the metal radiation patch 302 is connected with the "inverted U" structure; wherein, the metal radiation patch includes N fan-shaped metal patches expanding outward from the center, and the adjacent fan-shaped radiation patches The spacing is equal, and the spacing between adjacent fan-shaped radiation patches is Ws. In this embodiment, the number of N mentioned above is greater than 3 and less than 20.
  • the height of the notch wall determines the gain level of the dual circularly polarized antenna at low elevation angles.
  • left-handed circularly polarized radiation can be obtained;
  • feeding power to the second coaxial adapter 402 right-handed circularly polarized radiation can be obtained.
  • a pair of coaxial conversion joints can be realized by using SMA coaxial conversion joints.
  • the lower dielectric substrate is disposed on a metal bottom plate.
  • Embodiment 1 (certain aircraft is used as maritime satellite communication)
  • Step 1 The antenna unit is made of silver-plated metal copper, the cutout wall is made of Fpcb dielectric substrate, the power distribution network is made of F4B dielectric substrate, and the metal base is made of metal aluminum with low density.
  • Step 2 According to the design requirements of the system on the antenna's electrical performance, mechanical performance, three-proof (anti-mold, anti-moisture, anti-salt spray) and space size constraints, the design and conformal installation of the wide-beam circularly polarized antenna were carried out design.
  • the height of the antenna is about 0.1 times of the working wavelength, and the optimized 3dB beamwidth is 157 degrees.
  • Step 3 Prepare an inverted U-shaped structure by means of laser cutting and abrasive stamping.
  • the inverted U-shaped structure is made of metal copper sheet material with a thickness of 0.4mm, and the "inverted U"-shaped structure is prepared by laser cutting, and a circular arc is folded by stamping with a mold. Prepare 4 sets of antenna units at a time, and install the antenna units on the dielectric board in a rotationally distributed manner to form a 1 ⁇ 4 circularly polarized array. And using the feeding network printed on the lower dielectric substrate, the feeding of the circularly polarized antenna is completed through equal difference phase feeding.
  • Step 4 The metal base plate is prepared by CNC machine tool processing.
  • the metal base plate is cut, machine milled and other processes to complete the preparation of the metal base plate.
  • Step 5 Install the 1 ⁇ 4 circularly polarized area array on the metal base plate according to the conformal structure requirements of the antenna of the communication equipment to form a dual circularly polarized antenna with the characteristics of low profile, wide beam and conformal structure.
  • Embodiment 2 (a certain aircraft is used as a navigation antenna)
  • Step 1 The antenna unit is made of silver-plated metal copper, the cutout wall is made of Fpcb dielectric substrate, the power distribution network is made of F4B dielectric substrate, and the metal base is made of metal aluminum with low density.
  • Step 2 According to the design requirements of the system on the antenna's electrical performance, mechanical performance, three-proof (anti-mold, anti-moisture, anti-salt spray) and space size constraints, the design and conformal installation of the wide-beam circularly polarized antenna were carried out design.
  • the height of the antenna is approximately 0.1 times the operating wavelength, and the optimized 3dB beamwidth is increased by 47 degrees.
  • Step 3 Prepare the "inverted U" structure by means of laser cutting and abrasive stamping.
  • the inverted U-shaped structure is made of metal copper sheet material with a thickness of 0.4mm, and the "inverted U"-shaped structure is prepared by laser cutting, and a circular arc is folded by stamping with a mold. Prepare 4 sets of antenna units at a time, and install the antenna units on the dielectric board in a rotationally distributed manner to form a 1 ⁇ 4 circularly polarized array. And using the feeding network printed on the lower dielectric substrate, the feeding of the circularly polarized antenna is completed through equal difference phase feeding.
  • Step 4 The metal base plate is prepared by CNC machine tool processing.
  • the metal base plate is cut, machine milled and other processes to complete the preparation of the metal base plate.
  • Step 5 Install the 1 ⁇ 4 circularly polarized area array on the metal base plate according to the conformal structure requirements of the antenna of the communication equipment to form a dual circularly polarized antenna with the characteristics of low profile, wide beam and conformal structure.
  • FIG. 7 is the normalized far-field radiation pattern of the left-handed circularly polarized antenna used in the example at the center frequency f 0 .
  • FIG. 8 is a normalized far-field radiation pattern at the center frequency f0 of the right-handed circularly polarized antenna used in the example.
  • Fig. 7 it is the far-field radiation pattern of the antenna selected in the embodiment at the center frequency f 0 and the left-handed circular polarization state, as can be seen from the figure that the pattern is a "peach-shaped" directional radiation pattern, 3dB
  • the beam width is 158 degrees.
  • a device which includes the wide-angle dual circularly polarized antenna with enhanced gain at low elevation angles as described above.

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Abstract

本发明属于无线通信领域，提供了一种低仰角增益增强的宽角双圆极化天线及设备。其中，该低仰角增益增强的宽角双圆极化天线包括切口壁、C型馈电网络、下介质基板、上介质基板、倒U型馈电结构、金属辐射贴片和一对同轴转换接头；所述切口壁环绕设在下介质基板周围，所述C型馈电网络设于下介质基板的上表面；所述C型馈电网络设置有若干个馈电枝节和梳状人工表面等离激元结构，所述馈电枝节与倒U型馈电结构的馈电端连接；所述倒U型馈电结构设置于C型馈电网络与金属辐射贴片之间；所述金属辐射贴片设置于倒U型馈电结构的上侧且敷设在上介质基板的上表面；一对同轴转换接头设置于C型馈电网络末端且位于下介质基板下方。

Description

一种低仰角增益增强的宽角双圆极化天线及设备 技术领域
本发明属于无线通信领域，尤其涉及一种低仰角增益增强的宽角双圆极化天线及设备。
背景技术
本部分的陈述仅仅是提供了与本发明相关的背景技术信息，不必然构成在先技术。
随着现代通信技术的飞速发展，天线作为无线通信、雷达等系统的重要组成部分，天线性能的优劣在很大程度上直接影响着整个系统的性能。而在地球的低纬度(南、北纬)地区，由于天线低仰角处较差的增益会直接影响航空、卫星通信、雷达、遥控和遥测等通信系统的性能。此外，在卫星信号覆盖边缘区域以及飞行器处于横滚或纵摇等不固定姿态情况下，也会导致信号连接中断问题的发生。圆极化天线较线极化天线具有诸多优点：在抗干扰、抗衰落以及抗多径效应上具有优势；旋向正交性；接收任意极化来波，其辐射波也可由任意极化天线接收；圆极化波入射到对称目标时，反射波旋向逆转，这一特性在GPS和移动通信领域中用来抗雨雾干扰和多径反射。为了进一步提高导航系统的通信质量，尤其在卫星定位、导航等系统中要求天线具有圆极化以及低仰角处足够大的增益特性，以便有效捕获到低仰角处的微弱信号。此外，由于对高速目标在各种极化方式和气候条件下跟踪测量的需要，单一极化方式已很难满足以上所述的应用需求。
发明人发现，现有技术中为了获得广角辐射和宽带特性，通常采用在衬底集成腔上刻蚀平行狭缝和采用微带贴片混合模技术等方式提高天线低仰角增益，然而该种类型天线极化仍为单极化工作方式，且天线的损耗较大，严重影响着通信过程的信噪比质量。
发明内容
为了解决上述背景技术中存在的技术问题，本发明提供了一种传输损耗低、低仰角增益增强的宽角双圆极化天线及设备，其具有结构简单、成本低、低损耗和低仰角增益高等优点。
为了实现上述目的，本发明采用如下技术方案：
本发明的第一方面提供一种低仰角增益增强的宽角双圆极化天线，其包括切口壁、C型馈电网络、下介质基板、上介质基板、倒U型馈电结构、金属辐射贴片和一对同轴转换接头；
所述切口壁环绕设在下介质基板周围，所述C型馈电网络设于下介质基板的上表面；所述C型馈电网络设置有若干个馈电枝节和若干梳状人工表面等离激元结构，所述馈电枝节与倒U型馈电结构的馈电端连接；所述倒U型馈电结构设置于C型馈电网络与金属辐射贴片之间；所述金属辐射贴片设置于倒U型馈电结构的上侧且敷设在上介质基板的上表面；一对同轴转换接头设置于C型馈电网络末端且位于下介质基板下方。
作为一种实施方式，所述的切口壁高度决定所述双圆极化天线在低仰角处的增益水平。
作为一种实施方式，所述切口壁包括若干个金属片，这些金属片以下介质基板中心为圆心且以设定半径沿周向均匀分布。
作为一种实施方式，所述下介质基板的介电常数和上介质基板的介电常数相同。
作为一种实施方式，所述下介质基板的下表面全部覆设导电介质。
作为一种实施方式，所述C型馈电网络的结构内侧蚀刻若干均匀分布的梳状人工表面等离激元结构，所述C型馈电网络的结构外侧衍生出若干均匀分布的馈电枝节。
作为一种实施方式，所述倒U型馈电结构包括若干个相同的倒U型结构，且以设定半径沿着周向旋转式均匀分布。
作为一种实施方式，每个倒U型结构上均设置有馈电端和短路端，短路端与下介质基板下表面的导电介质短路连接。
作为一种实施方式，所述金属辐射贴片包括若干个从中心向外扩展的扇形金属贴片，相邻扇形辐射贴片间距相等。
作为一种实施方式，所述下介质基板设置在金属底板上。
本发明的第二个方面提供了一种设备，其包括如上述所述的低仰角增益增强的宽角双圆极化天线。
与现有技术相比，本发明的有益效果是：
本发明引入倒U型馈电结构和金属辐射贴片，使得天线的剖面高度小于0.2λ 0(λ 0为中心频率对用波长)；
本发明引入了人工表面等离激元技术，有效降低了微波网络的传输损耗，提高了天线的辐射增益和通信系统的信噪比，有效的改善了系统的通信质量。
本发明采用双端口馈电与多馈点相结合的技术，首先将天线的N个馈电均匀的分布在半径为D的圆周上，通过多馈点技术提高了天线的对称性，从而实 现了天线相位中心的稳定性设计；其次，采用双端口技术对天线进行馈电，实现了天线左旋、右旋两种极化工作方式的自由切换；
本发明引入了切口壁技术，有效提高了天线低仰角处增益，实现了天线的宽波束设计，改善了天线的辐射方向图。
本发明附加方面的优点将在下面的描述中部分给出，部分将从下面的描述中变得明显，或通过本发明的实践了解到。
附图说明
构成本发明的一部分的说明书附图用来提供对本发明的进一步理解，本发明的示意性实施例及其说明用于解释本发明，并不构成对本发明的不当限定。
图1(a)是本发明的单馈法微扰方式实施例1；
图1(b)是本发明的单馈法微扰方式实施例2；
图1(c)是本发明的单馈法微扰方式实施例3；
图2是本发明实施例的低仰角增益增强的宽角双圆极化天线立体图；
图3是本发明实施例的天线的C型馈电网络结构图；
图4是本发明实施例的天线的金属辐射贴片结构图；
图5是本发明实施例的天线的倒U型结构图；
图6是本发明实施例的天线的切口壁结构图；
图7是本发明实施例的天线在中心频率处左旋圆极化远场方向图；
图8是本发明实施例的天线在中心频率处右旋圆极化远场方向图。
图中：100、金属底板；101、切口壁；102、下介质基板；103、倒U型馈电安装孔；104、同轴转换接头安装孔；201、C型馈电网络；202、C型馈电网络第一末端；203、C型馈电网络第二末端；204、馈电枝节；205、梳状人工表 面等离激元；206、接地导体平面；300、上介质基板；301、倒U型馈电结构；302、金属辐射贴片；303、短路端；304、馈电端；401、第一同轴转换接头；402、第二同轴转换接头。
具体实施方式
下面结合附图与实施例对本发明作进一步说明。
应该指出，以下详细说明都是例示性的，旨在对本发明提供进一步的说明。除非另有指明，本文使用的所有技术和科学术语具有与本发明所属技术领域的普通技术人员通常理解的相同含义。
需要注意的是，这里所使用的术语仅是为了描述具体实施方式，而非意图限制根据本发明的示例性实施方式。如在这里所使用的，除非上下文另外明确指出，否则单数形式也意图包括复数形式，此外，还应当理解的是，当在本说明书中使用术语“包含”和/或“包括”时，其指明存在特征、步骤、操作、器件、组件和/或它们的组合。
目前圆极化天线相比于线极化有着更加广泛的应用，是天线理论中重要的课题之一。天线在实现圆极化方面有很多方法，比如给单个天线增加微扰的单点馈电法以及多点正交馈电法，还有用多个天线和馈电网络组成的多元法，这些都是天线实现圆极化辐射的常用方法。
单馈法的设计可以用空腔模型理论进行分析，其利用的是两个辐射正交极化的兼并模来实现圆极化。如图1(a)-图1(c)所示，通过对天线进行微扰等手段，使两种正交模式的谐振频率隔开，通过利用两个兼并模的等效阻抗相角的90度相位差(超前45度/滞后45度)效果，在远场区形成圆极化辐射。
单馈法因其结构简单，成本低，无需外加馈电网络等优点受到了广大工程 师的青睐。然而，对于单馈法的圆极化天线，由于其存在工作带宽窄、极化特性差以及低仰角处增益低等缺点。为了改善这种情况，通常采用多馈法和多元法，然而该方法在实现圆极化工作的过程中，由于微波网络的引入导致传输损耗的增加，而且无法实现天线的宽波束和双圆极化工作特性。因此，本实施例采用人工表面等离激元与多馈点相结合的馈电技术，不仅获得了具有低损耗特性的微波网络，而且实现了天线的双圆极化工作。此外，通过采用切口壁加载技术，进一步提高了天线低仰角处增益，实现了天线的宽波束工作特性。
参照图2，本实施例所形成的低仰角增益增强的宽角双圆极化天线，利用半径为Ro，高度为Hg的切口壁形成凹型圆环结构腔体，天线单元高度为H，天线以原点为圆心，半径为Ri周向旋转形成了本发明实例天线。
具体地，本实施例的一种低仰角增益增强的宽角双圆极化天线，其包括切口壁101、C型馈电网络201、下介质基板102、上介质基板300、倒U型馈电结构103、金属辐射贴片302和一对同轴转换接头。这一对同轴转换接头分别为第一同轴转换接头401和第二同轴转换接头402。
其中，所述切口壁101环绕设在下介质基板102上，如图3所示，所述C型馈电网络201设于下介质基板102的上表面；所述C型馈电网络201设置有若干馈电枝节204和人工表面等离激元205，所述馈电枝节204与倒U型馈电结构301的馈电端304连接；所述倒U型馈电结构301设置于C型馈电网络201与金属辐射贴片302之间；所述金属辐射贴片302设置于倒U型馈电结构301的上侧且敷设在上介质基板300的上表面；一对同轴转换接头设置于C型馈电网络末端且位于下介质基板下方。C型馈电网络末端包括两个，分别为C型馈电网络第一末端202和C型馈电网络第二末端203。所述的人工表面等离激元 205设置于C型馈电网络的内侧。其中，设置于端口202、203部分的人工表面等离激元，由外到内形成由低到高的传输过渡段(高度h1,h2,h3….hn)，而设置于C型馈电网络主体部分的梳状人工表面等离激元结构由若干高度相等(Hp)、宽度(wp)，均匀分布的梳状结构组成。接地导体平面206通过金属短路柱与介质层下表面的金属覆层段落连接。
在本实施例中，所述下介质基板102的介电常数和上介质基板300的介电常数相同。所述下介质基板102的下表面全部覆设导电介质，比如铜。
具体地，下介质基板102的介电常数为2.65，厚度T1，半径为Ro的F4B板材，下介质基板的下表面全部覆铜，上表面印刷有C型馈电网络201。所述的上介质基板300的介电常数为2.65，厚度T2，半径为Ri的F4B板材，其上表面覆盖金属辐射贴片302。
在具体实施中，如图6所示，切口壁101为金属材质。所述切口壁101包括若干个金属片，这些金属片以下介质基板中心为圆心且以设定半径沿周向均匀分布。
例如：切口壁101由N个宽度为Wg，高度为Hg的金属片，以整体结构中心为圆心，以Ro为半径沿周向均匀分布。切口壁101以原点为中心，数量为N个，沿着周向旋转形成单层薄壁凹型桶装结构，且固定于下介质基板102的上方，与下介质基板102的下表面金属覆铜短路连接，从而构成单层薄壁凹型盘状结构；所述下介质基板102圆形结构，其下表面覆盖金属铜，上表面印刷有C型馈电网络201。
在具体实施中，所述的C型馈电网络201设置于下介质基板102的上表面，其结构腹部连接有N个馈电枝节204，形成了星型结构分布的分支终端。所述 的C型馈电网络201的馈电网络末端与穿过同轴转换接头安装孔104的同轴转换接头的内芯相连接。所述的C型馈电网络内侧均匀分布的N个梳状凹凸结构，构成了用于低损耗传输的人工表面等离激元205；所述同轴转换接头设置于下介质基板102的下方，其外导体与下介质基板102的下表面金属覆铜相连接；
具体地，如图5所示，所述倒U型馈电结构包括若干个相同的倒U型结构，这些倒U型结构以设定半径沿着周向旋转式均匀分布。所述的倒U型馈电结构301设置于下介质基板102的上方，数量为N个，倒U型结构馈电端304安装于倒U型馈电安装孔103内并与馈电网络枝节204相连接，其倒U型结构短路端303与下介质基板102的下表面金属覆铜短路连接；
如图4所示，所述的金属辐射贴片302设置于倒U型馈电结构301的上部，印刷于上介质基板300的上表面，由N个从中心向边缘逐渐增宽的扇形结构做成，且金属辐射贴片302的圆弧部分与“倒U”型结构相连接；其中，所述金属辐射贴片包括N个从中心向外扩展的扇形金属贴片，相邻扇形辐射贴片间距相等，相邻扇形辐射贴片间距为Ws。在本实施例中，以上所述N的数量大于3，小于20。
在具体实施中，所述的切口壁高度决定所述双圆极化天线在低仰角处的增益水平。
改变切口壁(101)的高度Hg＝0.05～0.1λ 0(λ 0中心频率)，可以有效的提高圆极化天线在低仰角处的增益水平，展宽圆极化天线的3dB波束宽度；通过改变馈电网络末端SMA同轴转换接头的馈电顺序，获得天线的圆极化辐射功能。当给第一同轴转换接头401馈电时，可以获得左旋圆极化辐射；当给第二同轴转换接头402馈电时，可以获得右旋圆极化辐射。
在本实施例中，一对同轴转换接头可采用SMA同轴转换接头来实现。
在其他实施例中，所述下介质基板设置在金属底板上。
下面给出本实施例的双圆极化天线的具体应用：
实施例1：(某飞行器用作海事卫星通信)
第一步：天线单元选用表面镀银的金属铜材料，切口壁选用Fpcb介质基板，功分网络选用F4B介质基板，金属底板选用密度小的金属铝材料。
第二步：根据系统对天线的电性能、力学性能、三防(防霉菌、防潮湿、防盐雾)和空间尺寸约束的设计要求，进行了宽波束圆极化天线设计和共型化安装设计。该天线的高度约为工作波长的0.1倍，优化后的3dB波束宽度为157度。
第三步：采用激光切割和磨具冲压的方式制备倒U型结构。
该倒U型结构采用厚度0.4mm的金属铜片材料，通过激光切割进行“倒U”型结构的制备，并利用模具冲压折出圆弧。一次制备4套天线单元，将天线单元按照旋转分布的方式安装于介质板上，形成1×4圆极化面阵。并利用印刷在下介质基板上的馈电网络，通过等差相位馈电完成圆极化天线的馈电。
第四步：采用CNC数控机床加工的方式进行金属底板的制备。
按照通信设备的安装尺寸要求以及天线的结构特点，对金属底板进行切割、机铣等工艺完成金属底板的制备。
第五步：按照通信设备的天线共型结构要求，将1×4圆极化面阵安装于金属底板之上，形成具有低剖面、宽波束和结构共型等特点的双圆极化天线。
实施例2：(某飞行器用作导航天线)
第一步：天线单元选用表面镀银的金属铜材料，切口壁选用Fpcb介质基板，功分网络选用F4B介质基板，金属底板选用密度小的金属铝材料。
第二步：根据系统对天线的电性能、力学性能、三防(防霉菌、防潮湿、防盐雾)和空间尺寸约束的设计要求，进行了宽波束圆极化天线设计和共型化安装设计。该天线的高度约为工作波长的0.1倍，优化后的3dB波束宽度增加了47度。
第三步：采用激光切割和磨具冲压的方式制备“倒U”型结构。
该倒U型结构采用厚度0.4mm的金属铜片材料，通过激光切割进行“倒U”型结构的制备，并利用模具冲压折出圆弧。一次制备4套天线单元，将天线单元按照旋转分布的方式安装于介质板上，形成1×4圆极化面阵。并利用印刷在下介质基板上的馈电网络，通过等差相位馈电完成圆极化天线的馈电。
第四步：采用CNC数控机床加工的方式进行金属底板的制备。
按照通信设备的安装尺寸要求以及天线的结构特点，对金属底板进行切割、机铣等工艺完成金属底板的制备。
第五步：按照通信设备的天线共型结构要求，将1×4圆极化面阵安装于金属底板之上，形成具有低剖面、宽波束和结构共型等特点的双圆极化天线。
下面结合仿真结果作进一步说明：
利用商业仿真软件HFSS_19.0对上述实施方式中所采用的面阵天线左旋圆极化远场方向图进行仿真计算，结果如图7所示。其中，图7为实例中所采用的左旋圆极化天线在中心频率f 0处的归一化远场辐射方向图。
利用商业仿真软件HFSS_19.0对上述实施方式中所采用的面阵天线左旋圆极化远场方向图进行仿真计算，结果如图8所示。其中，图8为实例中所采用的右旋圆极化天线在中心频率f0处的归一化远场辐射方向图。
参照图7，为实施方式中所选取的天线在中心频率f 0及左旋圆极化状态下的 远场辐射方向图，从图中可以看出方向图为“桃型”定向辐射方向图，3dB波束宽度为158度。
参照图7，为实施方式中所选取的天线在中心频率f0及右旋圆极化状态下的远场辐射方向图，从图中可以看出方向图为“桃型”定向辐射方向图，3dB波束宽度为157度。
在其他实施例中，还提供了一种设备，其包括如上述所述的低仰角增益增强的宽角双圆极化天线。
以上所述仅为本发明的优选实施例而已，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种低仰角增益增强的宽角双圆极化天线，其特征在于，包括切口壁、C型馈电网络、下介质基板、上介质基板、倒U型馈电结构、金属辐射贴片和一对同轴转换接头；
    所述切口壁环绕设在下介质基板周围，所述C型馈电网络设于下介质基板的上表面；所述C型馈电网络设置有若干个馈电枝节和若干梳状人工表面等离激元结构，所述馈电枝节与倒U型馈电结构的馈电端连接；所述倒U型馈电结构设置于C型馈电网络与金属辐射贴片之间；所述金属辐射贴片设置于倒U型馈电结构的上侧且敷设在上介质基板的上表面；一对同轴转换接头设置于C型馈电网络末端且位于下介质基板下方。
  2. 如权利要求1所述的低仰角增益增强的宽角双圆极化天线，其特征在于，所述的切口壁高度决定所述双圆极化天线在低仰角处的增益水平。
  3. 如权利要求1所述的低仰角增益增强的宽角双圆极化天线，其特征在于，所述切口壁包括若干个金属片，这些金属片以下介质基板中心为圆心且以设定半径沿周向均匀分布。
  4. 如权利要求1所述的低仰角增益增强的宽角双圆极化天线，其特征在于，所述下介质基板的介电常数和上介质基板的介电常数相同。
  5. 如权利要求1所述的低仰角增益增强的宽角双圆极化天线，其特征在于，所述下介质基板的下表面全部覆设导电介质。
  6. 如权利要求1所述的低仰角增益增强的宽角双圆极化天线，其特征在于，所述C型馈电网络的结构内侧蚀刻若干均匀分布的梳状人工表面等离激元结构，所述C型馈电网络的结构外侧衍生出若干均匀分布的馈电枝节。
  7. 如权利要求5所述的低仰角增益增强的宽角双圆极化天线，其特征在于， 所述倒U型馈电结构包括若干个相同的倒U型结构，这些倒U型结构以设定半径沿着周向旋转式均匀分布。
  8. 如权利要求6所述的低仰角增益增强的宽角双圆极化天线，其特征在于，每个倒U型结构上均设置有馈电端和短路端，短路端与下介质基板下表面的导电介质短路连接。
  9. 如权利要求1所述的低仰角增益增强的宽角双圆极化天线，其特征在于，所述金属辐射贴片包括若干个从中心向外扩展的扇形金属贴片，相邻扇形辐射贴片间距相等；
    或
    所述下介质基板设置在金属底板上。
  10. 一种设备，其特征在于，包括如权利要求1-9中任一项所述的低仰角增益增强的宽角双圆极化天线。
PCT/CN2021/117250 2021-07-21 2021-09-08 一种低仰角增益增强的宽角双圆极化天线及设备 WO2023000462A1 (zh)

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Publication number Priority date Publication date Assignee Title
CN114464996B (zh) * 2022-02-11 2023-12-12 南京邮电大学 一种基于表面等离子体激元的圆极化阵列天线
CN114639949B (zh) * 2022-04-27 2024-01-05 上海海积信息科技股份有限公司 一种圆极化天线

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109546303A (zh) * 2018-11-06 2019-03-29 成都频岢微电子有限公司 一种基于超材料的小型化高增益圆极化天线
CN110190386A (zh) * 2019-03-25 2019-08-30 西安电子科技大学 一种宽带宽角轴比圆极化贴片天线
US20200006847A1 (en) * 2018-06-29 2020-01-02 Deere & Company Supplemental device for an antenna system
CN111682305A (zh) * 2020-05-25 2020-09-18 电子科技大学 一种用于卫星通信的低剖面圆极化微带天线
CN112467395A (zh) * 2020-10-30 2021-03-09 航天恒星科技有限公司 一种小型化低剖面双圆极化天线

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7639183B2 (en) * 2004-11-15 2009-12-29 Anritsu Corporation Circularly polarized antenna and radar device using the same
CN101286592B (zh) * 2008-06-13 2012-09-26 航天恒星科技股份有限公司 宽频带圆极化宽波束多模卫星导航终端天线
KR101087288B1 (ko) * 2009-03-31 2011-11-29 한국항공대학교산학협력단 위성통신용 원형 편파 안테나
CN106816691A (zh) * 2016-12-26 2017-06-09 上海交通大学 Uhf频段的小型化低剖面宽带圆极化复合水介质天线
CN107910648B (zh) * 2017-11-01 2020-04-17 山西大学 一种低剖面双频带全向圆极化天线

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200006847A1 (en) * 2018-06-29 2020-01-02 Deere & Company Supplemental device for an antenna system
CN109546303A (zh) * 2018-11-06 2019-03-29 成都频岢微电子有限公司 一种基于超材料的小型化高增益圆极化天线
CN110190386A (zh) * 2019-03-25 2019-08-30 西安电子科技大学 一种宽带宽角轴比圆极化贴片天线
CN111682305A (zh) * 2020-05-25 2020-09-18 电子科技大学 一种用于卫星通信的低剖面圆极化微带天线
CN112467395A (zh) * 2020-10-30 2021-03-09 航天恒星科技有限公司 一种小型化低剖面双圆极化天线

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
TANG ZHAOYANG, LIU JINHAI, YIN YINGZENG: "Enhanced Cross-Polarization Discrimination of Wideband Differentially Fed Dual-Polarized Antenna via a Shorting Loop", IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, IEEE, PISCATAWAY, NJ, US, vol. 17, no. 8, 1 August 2018 (2018-08-01), US , pages 1454 - 1458, XP093026389, ISSN: 1536-1225, DOI: 10.1109/LAWP.2018.2849221 *
TRAN HUY HUNG; PARK IKMO: "A Dual-Wideband Circularly Polarized Antenna Using an Artificial Magnetic Conductor", IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, IEEE, PISCATAWAY, NJ, US, vol. 15, 1 January 1900 (1900-01-01), US , pages 950 - 953, XP011604489, ISSN: 1536-1225, DOI: 10.1109/LAWP.2015.2483589 *

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