Four-arm helical antenna with patch loaded at top end

Abstract

The invention relates to the technical field of wireless communication, and particularly discloses a four-arm helical antenna. The antenna comprises a metal floor, a supporting medium and a radiation assembly which are sequentially arranged, wherein the radiation assembly is innovatively combined by a spiral arm structure and a top loading patch. The spiral arm is integrated on the surface of the supporting medium in a precise winding mode, the top end loading patches are printed on the upper surface and the lower surface of the circular medium substrate through a double-face copper-clad structure, and electrical connection is innovatively achieved through a three-dimensional interconnection structure. Four sets of metalized through holes in the outer side complete coupling connection of the patches and the spiral arm. The two groups of metalized through holes on the inner side are connected with an outer conductor of a coaxial feeder line, and the central metalized through hole is directly communicated with an inner conductor of the feeder line. According to the antenna, through unique spatial layout and impedance matching design, a complex feed network is not needed, the matching characteristic is good, the low-elevation radiation characteristic is good, the azimuth plane has the omnidirectional radiation characteristic, and the antenna is suitable for wireless systems needing full-space coverage such as satellite communication and navigation positioning.

Description

Technical Field

[0001] The invention relates to a four-arm helical antenna with a patch loaded on the top, belonging to the technical field of wireless communications. Background Art

[0002] In drone swarm collaboration and dynamic ad hoc network communication scenarios, antennas require full spatial coverage, lightweight structures, and multipath interference resistance. Helical antennas, with their omnidirectional beam coverage, wide elevation angle coverage, and circular polarization interference resistance, are the preferred solution in this area.

[0003] Quadrifilar helical antennas are widely used in drones and satellites. However, traditional quadrifilar helical antennas suffer from a conflict between the axial mode and the normal mode, preventing them from achieving strong radiation at both low elevation angles and the zenith, hindering their large-scale application in drone and satellite communications.

[0004] The innovation of the four-arm helical antenna with a top-loaded patch of the present invention lies in that a metal patch is loaded on the top of the four-arm helix and a top-feeding method is adopted, so that the metal patch can radiate toward the zenith, compensating for the weaker radiation intensity in the zenith area of ​​the axial mode. At the same time, no complex feeding network is required, simplifying the structure. Summary of the Invention

[0005] The present invention provides a quadrifilar helical antenna with a patch loaded on the top, which is used to solve the defects in the prior art of a complex feeding network and the inability to simultaneously have strong radiation in low elevation angles and zenith directions.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The quadrilateral helical antenna with a top-loading patch comprises a radome, a supporting medium, four helical arms, and a loading patch;

[0008] The radome is made of FR-4 epoxy resin;

[0009] The ratio of the helical pitch to the helical circumference is 3.3, and the number of turns is three;

[0010] The supporting medium is PMI foam;

[0011] The spiral arm is engraved on the F4BM220 dielectric board in a single-sided copper-clad manner, and is formed into a spiral rising shape perpendicular to the metal floor by covering the supporting dielectric;

[0012] The inner conductor of the coaxial line is connected to the upper patch and the lower patch through metal vias, and then connected to the two spiral wires through metal vias;

[0013] The outer conductor of the coaxial line is connected to the upper patch and the lower patch through a metal through-hole, and then connected to the two spiral wires through a metal via;

[0014] The quadrifilar helical antenna with a top-loaded patch according to the present invention has the following advantages compared to existing quadrifilar helical antennas:

[0015] 1. Use coaxial line for top feeding, no feeding network is required, and the structural complexity is reduced;

[0016] 2. Use top loading patch to improve matching performance and make up for the weak zenith radiation intensity of the axial mode; BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a schematic structural diagram of a top-loaded patch quadrifilar helical antenna embodiment 1 of the present invention;

[0018] Figure 2 A diagram showing the structure of the spiral arms of a quadrifilar helical antenna with a patch loaded on the top of the antenna;

[0019] Figure 3 A top patch structure diagram of a quadrifilar helical antenna with a top-loaded patch according to the present invention;

[0020] Figure 4 This is a structural diagram of the supporting medium and coaxial feed line of the quadrifilar helical antenna with a top-loaded patch according to the present invention;

[0021] Figure 5 This is the reflection coefficient simulation result of Example 1 of the quadrifilar helical antenna with a top-loaded patch of the present invention;

[0022] Figure 6 The simulation results of the main polarization and cross-polarization of the elevation direction pattern of the quadrifilar helical antenna with a top-loaded patch at 3.4 GHz in Example 1 of the present invention are as follows:

[0023] Figure 7 The simulation results of the main polarization and cross-polarization of the azimuth plane radiation pattern of the quadrifilar helical antenna embodiment 1 with a top-loaded patch at 3.4 GHz are shown;

[0024] Figure 8 The antenna gain simulation results of Example 1 of the quadrifilar helical antenna with a top-loaded patch of the present invention at a frequency of 3.3-3.6 GHz and a beam pointing angle of 90° are shown;

[0025] Illustration:

[0026] 11-support medium; 12-metal floor; 13-coaxial feed line; 2-radome; 31-first spiral arm; 312-second spiral arm; 313-third spiral arm; 314-fourth spiral arm; 32-spiral arm printed medium board; 41-patch printed medium board; 42-first upper layer patch; 421-second upper layer patch; 422-third upper layer patch; 423-first lower layer patch; 424-second lower layer patch; 425-third lower layer patch; 426-fourth lower layer patch; 43-center metal via; 431-first inner metal via; 432-second inner metal via; 433-third inner metal via; 434-fourth inner metal via; 435-first outer metal via; 436-second outer metal via; 437-third outer metal via; 438-fourth outer metal via. DETAILED DESCRIPTION

[0027] In order to better illustrate the purpose and advantages of the present invention, the quadrifilar helical antenna with a top-loaded patch of the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0028] Example 1

[0029] The structure of this embodiment is as follows Figure 1 As shown, this embodiment includes a supporting medium, a radome, four spiral arms, and a top-loading patch.

[0030] The spiral arms of this embodiment are as follows Figure 2 As shown, it includes a first spiral arm, a second double spiral arm, a third double spiral arm, and a fourth spiral arm, wherein the four spiral arms are overprinted on a dielectric plate in a single-sided copper coating manner, and then the dielectric plate is coated on a supporting dielectric to form a spiral shape;

[0031] The top loading patch of this embodiment is as follows Figure 3 As shown, it includes an upper patch and a lower patch, which are connected by metal vias;

[0032] The lower patch is connected to the spiral arm through the outer metal vias, the upper patch is connected to the coaxial feed line through the inner vias, and the coaxial feed line feeds power to the four spiral arms through the metal vias of the upper and lower patches.

[0033] Among them, the first double-ridge waveguide, the second double-ridge waveguide, the third double-ridge waveguide, the fourth double-ridge waveguide, the fifth double-ridge waveguide, the sixth double-ridge waveguide, and the seventh double-ridge waveguide are spaced 1 mm apart from each other;

[0034] Figure 4 This embodiment supports the medium and coaxial feeder structure.

[0035] Figure 5For the reflection coefficient simulation structure of this embodiment, the reflection coefficient is less than -18dB within 3.3-3.6GHz.

[0036] Figure 6 、 Figure 7 For this embodiment at the 3.4 GHz frequency, the main polarization and cross-polarization radiation patterns in the elevation and azimuth planes have a gain greater than 7 dB at ±90° in the elevation plane and a gain greater than -2 dB in the zenith direction; the gain in the azimuth plane is greater than 6.5 dB, and the non-circularity is better than ±1.5 dB.

[0037] Figure 8 This is the gain variation curve of this embodiment at 3.3-3.6 GHz when the beam is pointing at 90 degrees, and the gain fluctuation is better than ±1 dB.

[0038] The antenna of the present invention can be used in unmanned aerial vehicles and satellite communication systems that require beams to cover both low elevation angles and the zenith.

[0039] The above descriptions are only preferred embodiments of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A four-arm helical antenna, characterized in that: include: Metal flooring; radome; Support medium; four spiral arms, wherein the four spiral arms are wound around the supporting medium; The patch is loaded and engraved on the upper and lower surfaces of the dielectric substrate.

2. The quadrifilar helical antenna according to claim 2, wherein: The antenna cover (2) is made of FR-4 epoxy resin.

3. The quadrifilar helical antenna according to claim 2, wherein: The ratio of the pitch of the spiral arm (31) (312) (313) (314) to the spiral circumference is 3.3, and the number of turns is three.

4. The quadrifilar helical antenna according to claim 2, wherein: The supporting medium (1) is PMI foam.

5. The quadrifilar helical antenna according to claim 2, wherein: The spiral arm is engraved on the F4BM220 dielectric plate (32) in a single-sided copper coating manner, and is formed into a spiral rising shape perpendicular to the floor by coating the supporting medium (1).

6. The quadrifilar helical antenna according to claim 4, wherein: The loading patch (42) (421) (422) (423) (424) (425) (426) is overlaid on the F4BM220 dielectric board (41) in a double-sided copper-clad manner.

7. The quadrifilar helical antenna according to claim 5, wherein: The inner conductor of the coaxial line is connected to the upper patch (42) and the lower patch (423)(426) through a metal via (43), and then connected to the spiral line (31)(313) through a metal via (435)(437); The outer conductor of the coaxial line is connected to the upper patch (421) (422) and the lower patch (424) (425) through a metal through hole (431) (433), and is then connected to the spiral line (312) (314) through a metal via hole (434) (436).

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