Non-uniform compression high-order mode quadrifilar helix antenna with beam width enhancement

Abstract

The invention discloses a non-uniform compression high-order mode four-arm helical antenna with enhanced beam width, which comprises a hollow dielectric cylinder and four helical arms printed on the outer surface of the hollow dielectric cylinder, and is characterized in that the bottom end of the hollow dielectric cylinder is connected with the upper surface of a circular dielectric substrate; the upper surface of the dielectric substrate is printed with a one-to-four Wilkinson power divider which has a 90-degree phase difference between adjacent ports, and the Wilkinson power divider is used as a feed network of the antenna. Non-uniform compression is carried out on the middle part of the three-time mode of the spiral arm, and the current mode is kept unchanged while the number of spiral turns is reduced; a section of straight line is added in the middle of each bent part, so that the coupling effect between the bent parts is reduced; the triple-mode spiral arms are non-uniformly compressed, so that the number of spiral turns is reduced, the half-power beam width is increased, the axial ratio width is not affected, the axial height of the antenna is reduced, and the miniaturization trend is met.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a non-uniform compression high-order mode quadrifilar helical antenna with enhanced beam width, covering the S-band satellite communication frequency band (2.491.75±0.015GHz). Background Art

[0002] In satellite communications and navigation applications, at low elevation angles (Theta = 85°), signals may be affected by multipath effects and signal attenuation caused by weather conditions such as rain. Furthermore, the satellite is not always directly overhead, so antennas must maintain excellent performance at all angles. Quadrifilar helical antennas, with their cardioid radiation pattern and excellent circular polarization performance and directivity in multiple directions, are widely used in satellite communications and navigation. However, the performance of existing quadrifilar helical antennas requires further design and improvement to meet the needs of communications technology. Summary of the Invention

[0003] The present invention aims to overcome the shortcomings and drawbacks of existing technologies by providing a non-uniformly compressed high-order mode quadrifilar helical antenna with enhanced beamwidth. This antenna non-uniformly compresses a cubic mode quadrifilar helical antenna, reducing the number of turns while maintaining the cubic mode. This increases the antenna's half-power beamwidth and reduces the antenna's axial length by 35.7%.

[0004] The present invention is achieved in that:

[0005] A non-uniformly compressed high-order mode four-arm helical antenna with enhanced beamwidth comprises a hollow dielectric cylinder and four spiral arms printed on the outer surface of the spatial dielectric cylinder. The bottom end of the hollow dielectric cylinder is connected to the upper surface of a circular dielectric substrate. A Wilkinson power divider with a one-to-four power divider and a 90° phase difference between adjacent ports is printed on the upper surface of the dielectric substrate as the antenna's feeding network.

[0006] Preferably, metal copper is arranged on the lower surface of the dielectric substrate as an antenna ground.

[0007] Preferably, the diameter of the spatial medium cylinder is 11.5 mm, the thickness is 2 mm, and the axial height is 45 mm.

[0008] Preferably, the dielectric constant of the spatial dielectric cylinder is 10.2, and the dielectric loss angle is 0.00029.

[0009] Preferably, the dielectric substrate has a radius of 34 mm and a thickness of 1.27 mm.

[0010] Preferably, the dielectric constant of the dielectric substrate is 6.15, and the dielectric loss angle is 0.0028.

[0011] Preferably, the lower surface of the dielectric substrate has an SMA feeding point connected to the input port of the feeding network.

[0012] Preferably, the feed network has three isolation resistors.

[0013] Preferably, the four spiral arms are evenly spaced apart and spirally wound on the outer surface of the spatial dielectric cylinder, and each of the spiral arms is connected to an output port of the feeding network.

[0014] Preferably, the spiral arm includes at least two bent compression parts located in the middle formed by bending up and down 90 degrees, and the width of the bent compression part is smaller than the width of the spiral arm body located outside it; adjacent bent compression parts are connected by a straight line segment.

[0015] The present invention performs non-uniform compression on the middle part of the cubic mode of the spiral arm, thereby reducing the number of spiral turns while maintaining the current mode unchanged; by adding a straight line in the middle of the bent part, the coupling effect between the bent parts is reduced; the non-uniform compression of the cubic mode spiral arm reduces the number of spiral turns and thus increases the half-power beamwidth without affecting the axial ratio width, while reducing the axial height of the antenna, which is in line with the trend of miniaturization.

[0016] After simulation optimization, the antenna of the present invention has a half-power beamwidth greater than 180°, an omnidirectional axial width of approximately 200°, a return loss less than -10dB in the 1.96GHz to 2.74GHz frequency range, and an impedance bandwidth of 33.2%. Furthermore, compared to an uncompressed cubic-mode quadrifilar helical antenna, the axial height is reduced by 35.7%. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a front view of an antenna according to an embodiment of the present invention;

[0018] Figure 2 is a top view of an antenna according to an embodiment of the present invention;

[0019] Figure 3 is a bottom view of an antenna according to an embodiment of the present invention;

[0020] Figure 4 is an axonometric diagram of an antenna according to an embodiment of the present invention.

[0021] Figure 5 Schematic diagram of a non-uniformly compressed cubic mode spiral arm of an antenna according to an embodiment of the present invention.

[0022] Figure 6 1 is a return loss diagram of the antenna simulation and test according to an embodiment of the present invention.

[0023] Figure 7 This is the antenna directional pattern of the embodiment of the present invention at 2.49 GHz, with antenna Phi = 0°.

[0024] Figure 8 The antenna of the embodiment of the present invention has a Phi = 90° directional pattern at 2.49 GHz.

[0025] Figure 9 This is a diagram of the antenna according to an embodiment of the present invention at 2.49 GHz with an axial ratio of Phi = 0°.

[0026] Figure 10 This is a diagram of an axial ratio of the antenna of an embodiment of the present invention at 2.49 GHz with antenna Phi = 90°. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] The present invention achieves the goal of reducing the volume of the antenna while maintaining or even enhancing the performance of the antenna beam width and the like by bending and compressing the spiral arms of the antenna.

[0029] like Figures 1 to 4 As shown, in an exemplary embodiment of the present application, the non-uniform compressed high-order mode four-arm helical antenna with enhanced beam width includes a hollow dielectric cylinder and four spiral arms printed on the outer surface of the spatial dielectric cylinder, the bottom end of the hollow dielectric cylinder is connected to the upper surface of a circular dielectric substrate, and the upper surface of the dielectric substrate is printed with a Wilkinson power divider that divides one into four and has a 90° phase difference between adjacent ports as the antenna feeding network.

[0030] In one embodiment, the spiral arms are printed on a hollow dielectric cylinder with a diameter of 11.5 mm, a thickness of 2 mm, an axial height of 45 mm, a dielectric constant of 10.2, and a dielectric loss factor of 0.00029.

[0031] In one embodiment, the one-to-four Wilkinson power divider with a 90° phase difference between adjacent ports is used as the antenna feeding network, printed on the upper surface of a dielectric substrate with a radius of 34 mm, a thickness of 1.27 mm, a dielectric constant of 6.15, and a dielectric loss angle of 0.0028, and fed by SMA.

[0032] In one embodiment, there are three isolation resistors (110Ω) on the feed network.

[0033] In one embodiment, the lower surface of the dielectric substrate is made of metal copper as the antenna ground.

[0034] In an exemplary embodiment of the present application, the four-arm helical antenna with non-uniformly compressed high-order modes with enhanced beam width can widen the half-power beam width by utilizing the high-order modes of the four-arm helical antenna with a specific hollow dielectric cylinder radius and wall thickness; by non-uniformly compressing the spiral arms, the number of spiral turns of the antenna is reduced, which helps to further widen the half-power beam width of the antenna.

[0035] like Figures 1 to 4 As shown in the figure, a quadrifilar helical antenna with a non-uniform compression of the cubic mode is fed by a Wilkinson power divider with a one-to-four split and a 90° phase difference between adjacent ports. In the initial stage, an uncompressed cubic mode quadrifilar helical antenna was designed. Compared with other current modes, it has a wider half-power beamwidth that meets the design requirements. In the first stage, the middle part of the cubic mode spiral arm is bent and compressed (please refer to Figure 5 As shown in Figure 2, although the number of spiral turns is reduced, the beam width does not increase due to the coupling effect of the compressed part of the antenna. In the second stage, a straight line segment is added in the middle of the compressed part, as shown in Figure 2. Figure 5 As shown in the figure, the coupling effect is reduced, the number of antenna spiral turns is reduced, the half-power beamwidth is increased, and the circular polarization performance is not affected. At the same time, the axial height of the antenna is reduced by 35.7%.

[0036] In the embodiment of this application, Figure 5 As shown, in the at least two bent compression parts formed by bending up and down 90 degrees in the middle of the spiral arm, the width of the bent compression part is smaller than the width of the spiral arm body located outside it; adjacent bent compression parts are connected by a straight line segment, and preferably, the width of the straight line segment is larger than the width of the bent compression part and smaller than the width of the spiral arm body outside the bent compression part.

[0037] More preferably, the two separated arms of the bending compression portion have the same width, which is approximately half the width of the spiral arm body on the outside of the bending compression portion. Each bending compression portion includes a U-shaped portion located on one side of the length direction of the spiral arm and another U-shaped portion located on the other side opposite to the length direction of the spiral arm. The two U-shaped portions share one arm to be connected.

[0038] In an exemplary embodiment of the present application, the specific size of the antenna is determined through simulation. Figure 3 The specific structure of the spiral arm. Figure 6 The simulation and test results of antenna return loss. Figure 7 、 Figure 8 is the directional pattern of the antenna at Phi = 0° and Phi = 90° at 2.49 GHz. Figure 9 、 Figure 10 is the axial ratio of the antenna at 2.49 GHz between Phi = 0° and Phi = 90°.

[0039] After processing and testing: the antenna achieves wide beam and good circular polarization characteristics in the S-band 2.49GHz.

[0040] The basic principles, main features and advantages of the present invention are shown and described above. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0041] The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the claims are therefore intended to be embraced therein.

[0042] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A non-uniform compressed high-order mode quadrifilar helical antenna with enhanced beamwidth, characterized in that: The antenna comprises a hollow dielectric cylinder and four spiral arms printed on the outer surface of the hollow dielectric cylinder. The bottom end of the hollow dielectric cylinder is connected to the upper surface of a circular dielectric substrate. The upper surface of the dielectric substrate is printed with a one-to-four Wilkinson power divider with a 90° phase difference between adjacent ports as the antenna feeding network.

2. The non-uniform compressed high-order mode quadrifilar helical antenna with enhanced beamwidth according to claim 1, characterized in that: The lower surface of the dielectric substrate is provided with metal copper as an antenna ground plane.

3. The non-uniform compression high-order mode quadrifilar helical antenna with enhanced beamwidth according to claim 1, characterized in that: The diameter of the spatial medium cylinder is 11.5 mm, the thickness is 2 mm, and the axial height is 45 mm.

4. The non-uniform compression high-order mode quadrifilar helical antenna with enhanced beamwidth according to claim 1, characterized in that: The dielectric constant of the spatial dielectric cylinder is 10.2, and the dielectric loss angle is 0.00029.

5. The non-uniform compression high-order mode quadrifilar helical antenna with enhanced beamwidth according to claim 1, characterized in that: The dielectric substrate has a radius of 34 mm and a thickness of 1.27 mm.

6. The non-uniform compressed high-order mode quadrifilar helical antenna with enhanced beamwidth according to claim 1, characterized in that: The dielectric constant of the dielectric substrate is 6.15, and the dielectric loss angle is 0.0028.

7. The non-uniform compression high-order mode quadrifilar helical antenna with enhanced beamwidth according to claim 1, characterized in that: The lower surface of the dielectric substrate is provided with an SMA feeding point connected to the input port of the feeding network.

8. The non-uniform compression high-order mode quadrifilar helical antenna with enhanced beamwidth according to claim 1, characterized in that: The feed network has three isolation resistors.

9. The non-uniform compression high-order mode quadrifilar helical antenna with enhanced beamwidth according to claim 1, characterized in that: The four spiral arms are evenly spaced apart and spirally wound on the outer surface of the spatial medium cylinder, and each of the spiral arms is connected to an output port of the feeding network.

10. The non-uniform compression high-order mode quadrifilar helical antenna with enhanced beamwidth according to claim 1, characterized in that: The spiral arm includes at least two bent and compressed parts located in the middle and formed by bending up and down 90 degrees. The width of the bent and compressed part is smaller than the width of the spiral arm body located outside it; adjacent bent and compressed parts are connected by a straight line segment.

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