A suspended capacitive coupling-fed ultra-wideband circularly polarized antenna array

Abstract

The invention relates to an ultra-wideband circularly polarized antenna array of suspended capacitive coupling feeding, comprising a top dielectric substrate layer, a bottom dielectric substrate layer being connected below the top dielectric substrate layer through a nylon column, a plurality of metal radiation patches being arranged on the upper side of the top dielectric substrate layer, the metal radiation patches being arranged in a circular array with the center of the upper side of the top dielectric substrate layer as the center of the circle, and an angle between adjacent metal radiation patches being 60 degrees, two circular metal disks being arranged below the top dielectric substrate layer, the circular metal disks not being in contact with the top dielectric substrate layer, the two circular metal disks being orthogonally placed, and the orthogonal focus being located at the center of the metal radiation patch, and a coaxial line being connected at the center of the circular metal disk; the invention has the advantages of ultra-wideband, high gain, good circular polarization axis ratio performance, simple structure, low profile, light weight, and easy manufacture.

Description

Technical Field

[0001] The invention belongs to the technical field of wireless communications, and in particular relates to an ultra-wideband circularly polarized antenna array with suspended capacitive coupling feeding. Background Art

[0002] Antenna is an important part of wireless communication system, and its performance directly affects the performance of wireless communication system. In aerospace and satellite applications, higher requirements are put forward for the lightweight, miniaturization, wide bandwidth and circular polarization characteristics of antenna. In terms of antenna selection, microstrip antenna has the advantages of low profile, light weight and low cost, but its inherent narrow band characteristics (generally less than 5% relative bandwidth) limit its application scope. People have adopted many technologies to widen the bandwidth of microstrip antenna, such as irregular metal patches and laminated structures. However, irregular metal patches are difficult to design and often affect the polarization performance of antennas; laminated structures are simple to design and easy to ensure the polarization performance of antennas, but the height is difficult to control. In addition, in order to achieve circular polarization, a single feed point plus perturbation patch structure can be used. In this way, the circular polarization axis ratio bandwidth is narrower; multi-feed point technology can also be used to achieve circular polarization, and a wider circular polarization axis ratio bandwidth can be achieved by reasonably designing the feeding network.

[0003] After searching patents and documents, the patents and documents closely related to the present invention are as follows: Patent application number: CN200810114878.2, patent name: Circularly polarized broadband capacitance compensation probe fed laminated microstrip antenna array, which achieves a standing wave bandwidth greater than 20% through laminated structure and capacitance compensation probe technology; Patent application number: CN201510245290.0, patent name: A compact circularly polarized microstrip antenna and an antenna array composed thereof, which digs grooves on the surface of the radiation patch The equivalent inductance is increased to achieve antenna miniaturization, and the array element spacing is reduced to 0.6; the patent application number is: CN201520762559.8, and the patent name is portable circularly polarized microstrip antenna array. Through coupling capacitor feeding, only the standing wave bandwidth less than 2 is achieved, the bandwidth is greater than 20%, and the axial ratio bandwidth less than 3dB is greater than 15%; some researchers have used planar capacitor coupling to achieve an impedance bandwidth of less than -10dB and 50% in the millimeter wave band, but the gain is low and it is dual-polarized (see reference: MarkoSonkki ,et al.(2020),“Wideband Dual-Polarized Patch Antenna with Capacitive Coupling for mm-Wave Bands”2020 14th European Conference on Antennas and Propagation (EuCAP)); Some researchers have also used parasitic patches and multi-feed technology to achieve an impedance bandwidth of less than -10dB of 27% and an axial ratio bandwidth of less than 3dB of 16% in the GPS band, and a gain of 8dBi in the working frequency band (see reference: Shiqiang Fu ,(2014),“Broadband Circularly Polarized Microstrip Antennawith Coplanar Parasitic Ring Slot Patch for L-Band Satellite System Application”IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS).

[0004] In summary, it is easy to implement in engineering to broaden the working bandwidth of microstrip antennas by adopting some technical measures, but it often leads to problems such as deterioration of the circular polarization characteristics of the antenna and increase in antenna height. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an ultra-wideband circularly polarized antenna array with ultra-wideband, good circular polarization axis ratio performance, simple structure, low profile, light weight, easy production, and can be widely used in radar, satellite communication, WiFi, Bluetooth and other wireless communication technologies.

[0006] The technical solution of the present invention is as follows:

[0007] A suspended capacitive coupling-fed ultra-wideband circularly polarized antenna array, comprising a top dielectric substrate layer, a bottom dielectric substrate layer is connected to the top dielectric substrate layer via a nylon column, a plurality of metal radiation patches are arranged on the upper side of the top dielectric substrate layer, the metal radiation patches are arranged in a circular array with the center of the upper side of the top dielectric substrate layer as the center, and the angle between adjacent metal radiation patches is 60°;

[0008] Two circular metal disks are arranged below the metal radiation patch and are located below the top dielectric substrate layer. The circular metal disks are not in contact with the top dielectric substrate layer. The two circular metal disks are placed orthogonally and the orthogonal focus is located at the center of the metal radiation patch. A coaxial line is connected to the center of the circular metal disk, and the coaxial line is connected to a feeding network located on the lower side of the bottom dielectric substrate layer. A metal floor layer is arranged on the upper side of the bottom dielectric substrate layer.

[0009] Furthermore, the feeding network includes seven one-in-two Wilkinson power dividers, two one-in-three-sixth-order Wilkinson power dividers and their phase-shifting network, wherein six of the seven one-in-two Wilkinson power dividers are connected to microstrip line ends through phase-shifting networks, the six one-in-two Wilkinson power dividers with microstrip line ends are divided into two groups with three in each group, one end of each one-in-three-sixth-order Wilkinson power divider is connected to a group of one-in-two Wilkinson power dividers with microstrip line ends through a phase-shifting network, and the one-in-two Wilkinson power divider without a microstrip line end is respectively connected to the other ends of two one-in-three-sixth-order Wilkinson power dividers, and the microstrip line end is connected to a coaxial line.

[0010] Furthermore, the material of the top dielectric substrate layer and the bottom dielectric substrate layer is FR-4.

[0011] Furthermore, the coaxial line is specifically a metal cylinder with a diameter of 1.2 mm.

[0012] Furthermore, there is air between the top dielectric substrate layer and the circular metal disk.

[0013] Furthermore, the center distance between the two metal radiation patches is 0.58 ,in is the wavelength of the center frequency of the antenna's operating frequency band.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The present invention adopts a broadband phase-shifted feeding network and a capacitive coupling feeding technology to increase the impedance bandwidth and circular polarization axial ratio bandwidth of the antenna, and adopts a sequential rotation array to further improve the circular polarization axial ratio performance, wherein the standing wave bandwidth less than 2 is greater than 40%, and the axial ratio bandwidth less than 3dB is greater than 100%. The overall structure is simple, easy to manufacture, light weight, small size, and low profile, and is suitable for application in wireless communication systems.

[0016] In summary, the present invention has the effects of ultra-wideband, good circular polarization axis ratio performance, simple structure, low profile, light weight, and easy production, and can be widely used in wireless communication technology fields such as radar, satellite communication, WiFi, and Bluetooth. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention;

[0018] Figure 2 It is a front view schematic diagram of the capacitive coupling structure of the present invention;

[0019] Figure 3 is a schematic diagram of a capacitive coupling structure of the present invention;

[0020] Figure 4 Schematic diagram of the feeding network of the present invention.

[0021] Figure 5 It is a schematic diagram of the overall structural dimensions of the present invention.

[0022] Figure 6 This is a diagram showing the axial ratio results of the array structure in the 1-4 GHz frequency band in an embodiment of the present invention;

[0023] Figure 7 This is a graph showing the standing wave ratio results of the array structure in the 1-4 GHz frequency band in an embodiment of the present invention;

[0024] Figure 8 This is a graph showing the S11 results of the array structure in the 1-4 GHz frequency band according to an embodiment of the present invention;

[0025] In the figure, 1. top dielectric substrate layer, 2. bottom dielectric substrate layer, 3. nylon column, 4. metal radiation patch, 5. circular metal disk, 6. coaxial line, 7. metal floor layer, 8. feeding network, 9. one-to-two Wilkinson power divider, 10. one-to-three-sixth-order Wilkinson power divider, 11. phase shifting network, 12. end of microstrip line. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] like Figure 1-8 As shown, a suspended capacitive coupling-fed ultra-wideband circularly polarized antenna array comprises a top dielectric substrate layer 1, a bottom dielectric substrate layer 2 is connected to the top dielectric substrate layer 1 via a nylon column 3, a plurality of metal radiation patches 4 are printed on the upper side of the top dielectric substrate layer 1 via a printed circuit board etching process, the metal radiation patches 4 are arranged in a circular array with the center of the upper side of the top dielectric substrate layer 1 as the center, and the angle between adjacent metal radiation patches 4 is 60°;

[0028] Two circular metal plates 5 are arranged below the metal radiation patch 4 and are located below the top dielectric substrate layer 1. The circular metal plates 5 are not in contact with the top dielectric substrate layer 1. The two circular metal plates 5 are placed orthogonally and the orthogonal focus is located at the center of the metal radiation patch 4. A coaxial line 6 is connected to the center of the circular metal plates 5. The coaxial line 6 is connected to a feed network 8 located on the lower side of the bottom dielectric substrate layer 2. The feed network 8 is printed on the bottom dielectric substrate layer 2 by an etching process of a printed circuit board. A metal floor layer 7 is arranged on the upper side of the bottom dielectric substrate layer 2.

[0029] The impedance bandwidth and circular polarization axial ratio bandwidth of the antenna are increased by using a broadband phase-shifted feeding network 8, dual-feed capacitor coupling and sequential rotation feeding technology. The standing wave bandwidth less than 2 is greater than 40%, and the axial ratio bandwidth is all less than 3dB in the designed frequency band.

[0030] The designed circularly polarized microstrip antenna array has a center frequency of 2.1 GHz and an operating frequency band of 1.5-3.5 GHz.

[0031] In this embodiment, the feeding network 8 includes seven one-to-two Wilkinson power dividers 9, two one-to-three-sixth-order Wilkinson power dividers 10 and their phase shift network 11, wherein six of the seven one-to-two Wilkinson power dividers 9 are connected to a microstrip line end 12 through the phase shift network 11, and the six one-to-two Wilkinson power dividers 9 with the microstrip line end 12 are divided into two groups with three in each group, and one end of each one-to-three-sixth-order Wilkinson power divider 10 is connected to a group of one-to-two Wilkinson power dividers 9 with a microstrip line end 12 through the phase shift network 11, and the one-to-two Wilkinson power dividers 9 without the microstrip line end 12 are respectively connected to the other ends of the two one-to-three-sixth-order Wilkinson power dividers 10, and the microstrip line end 12 is connected to the coaxial line 6;

[0032] When in use, the one-to-three-sixth order Wilkinson power divider 10 realizes the functions of wide bandwidth, low loss and high isolation, the one-to-three-sixth order Wilkinson power divider 10 and the one-to-two Wilkinson power divider 9 realize the power distribution of the six metal radiation patches 4, and the phase shift network 11 realizes the function of 60° phase difference of equal power signals.

[0033] In this embodiment, the material of the top dielectric substrate layer 1 and the bottom dielectric substrate layer 2 is 0.8 mm thick FR-4, which is a commonly used glass epoxy resin material.

[0034] In this embodiment, the coaxial line 6 is specifically a metal cylinder with a diameter of 1.2 mm.

[0035] In this embodiment, there is air between the top dielectric substrate layer 1 and the circular metal disk 5, which can be adjusted according to the actual conformal scenario, which can not only provide actual support and protection but also widen the resonance frequency and improve the working bandwidth of the unit structure.

[0036] In this embodiment, if Figure 5 As shown, D is defined as the array element spacing. On the basis of not generating grating lobes, the array element spacing of the antenna array is set to 0.58 ( The wavelength of the center frequency of the working frequency band of the present invention is 145 mm, compared with the general 0.7 The structure is more compact by adjusting the element spacing of the metal radiation patch 4. The radius of the metal radiation patch 4 can adjust the resonant frequency. S is the distance between the circular metal disk 5 and the top dielectric substrate. By adjusting S ( Figure 2 ) and can optimize the unit bandwidth; r3 is the radius of the upright metal column, r2 is the radius of the circular metal disk 5, wherein, in this embodiment, S=2.7mm, r1=28.75mm, r2=4.5mm, r3=0.59mm;

[0037] In order to intuitively reflect the circular polarization performance of the structure in the working frequency band, the axial ratio, voltage standing wave ratio and S11 parameters of the structure in 1-4GHz are obtained in the HFSS commercial simulation software;

[0038] The axis ratio results are as follows Figure 6 As shown, in the working frequency band, the axial ratios are all less than 3GHz; the voltage standing wave Figure 7 As shown, the bandwidth of the standing wave less than 2 is greater than 40%; the S11 result is as follows Figure 8 As shown, the range from 1 to 4 GHz is all below -10 dB.

[0039] The working principle of the present invention is as follows: when the wideband circularly polarized microstrip antenna array is in the transmitting state, the received energy is evenly distributed through the feeding network 8, and the energy is coupled to the metal radiation patch 4 through the circular metal disk 5, and the metal radiation patch 4 radiates the energy into the free space. The receiving state is the opposite process.

[0040] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A suspended capacitive coupling-fed ultra-wideband circularly polarized antenna array, characterized in that: It comprises a top dielectric substrate layer, a bottom dielectric substrate layer is connected to the top dielectric substrate layer through a nylon column, a plurality of metal radiation patches are arranged on the upper side of the top dielectric substrate layer, the metal radiation patches are arranged in a circular array with the center of the upper side of the top dielectric substrate layer as the center, and the angle between adjacent metal radiation patches is 60°; Two circular metal disks are arranged below the metal radiation patch and are located below the top dielectric substrate layer. The circular metal disks are not in contact with the top dielectric substrate layer. The two circular metal disks are orthogonally placed and the orthogonal focus is located at the center of the metal radiation patch. A coaxial line is connected to the center of the circular metal disks. The coaxial line is connected to a feeding network located on the lower side of the bottom dielectric substrate layer. A metal floor layer is arranged on the upper side of the bottom dielectric substrate layer. The feeding network includes seven one-to-two Wilkinson power dividers, two one-to-three-sixth-order Wilkinson power dividers and a phase-shifting network, wherein six of the seven one-to-two Wilkinson power dividers are connected to microstrip line ends through a phase-shifting network, the six one-to-two Wilkinson power dividers with microstrip line ends are divided into two groups with three in each group, one end of each one-to-three-sixth-order Wilkinson power divider is connected to a group of one-to-two Wilkinson power dividers with microstrip line ends through a phase-shifting network, and the one-to-two Wilkinson power dividers without microstrip line ends are respectively connected to the other ends of two one-to-three-sixth-order Wilkinson power dividers, and the microstrip line ends are connected to a coaxial line.

2. The suspended capacitive coupling-fed ultra-wideband circularly polarized antenna array according to claim 1, characterized in that: The material of the top dielectric substrate layer and the bottom dielectric substrate layer is FR-4.

3. The suspended capacitive coupling-fed ultra-wideband circularly polarized antenna array according to claim 2, characterized in that: The coaxial line is specifically a metal cylinder with a diameter of 1.2 mm.

4. The suspended capacitive coupling-fed ultra-wideband circularly polarized antenna array according to claim 3, characterized in that: There is air between the top dielectric substrate layer and the circular metal disk.

5. The suspended capacitive coupling-fed ultra-wideband circularly polarized antenna array according to claim 4, characterized in that: The center distance between the two metal radiation patches is 0.58 ,in is the wavelength of the center frequency of the antenna's operating frequency band.

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