Dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics

Abstract

This invention discloses a dual-band quadrifilar helical antenna with both ultra-low profile and wide-angle radiation characteristics. The antenna comprises a first annular dielectric substrate, a sickle-shaped radiating arm, an FPC dielectric substrate, a helical radiating arm, an annular support, a cover film, a base plate, and a coaxial feed. Within the operating frequency band of satellite navigation, the antenna achieves a wide axial ratio beamwidth, a wide half-power beamwidth, and high gain. Furthermore, the antenna's ultra-low profile enables the implementation of low-wind resistance and high-sensitivity satellite navigation terminals onboard unmanned aerial vehicles, effectively improving the accuracy and speed of positioning for high-speed moving vehicles.

Description

Technical Field

[0001] The present invention relates to the field of satellite navigation antennas, and in particular to a dual-frequency four-arm helical antenna with both ultra-low profile and wide-angle radiation characteristics. Background Art

[0002] In the field of drone applications, with the continuous advancement and innovation of technology, the positioning accuracy and speed requirements for high-speed moving vehicles are increasing. To meet this demand, designing a navigation terminal with low wind resistance and high sensitivity is particularly important. Antennas, as a key component of navigation terminals, have a direct impact on the drone's positioning accuracy and communication stability. During flight, drones rely on satellite navigation systems for precise positioning and navigation. Traditional satellite navigation antennas are often large and have high profiles, which not only increases the drone's wind resistance but also limits its application in complex environments. Furthermore, traditional antennas have a narrow beamwidth, making them unable to meet the drone's requirements for rapid satellite search and stable tracking in vast airspace.

[0003] To improve the flight efficiency and positioning accuracy of drones, it is necessary to develop a satellite navigation antenna with a low profile and wide-angle radiation characteristics. A low-profile antenna can reduce the drone's wind resistance and improve flight efficiency; wide-angle radiation allows the antenna to cover more satellite signals, improving satellite search speed and positioning accuracy. Low-profile antennas are also easier to integrate with the drone body, reducing the antenna's impact on the drone's appearance. Furthermore, wide-angle radiation performance ensures that the drone can maintain stable positioning even when signals are weak or interfered with. Because single-frequency antennas have a limited signal reception frequency, dual-frequency and multi-frequency antennas hold great research potential. In recent years, many researchers have focused on achieving low-profile performance in drone-mounted satellite navigation antennas. However, some antennas, in order to achieve a low profile, reduce the vertical component of radiation, making it difficult to achieve wide-beam performance. Some low-profile antennas are still not low enough to meet the requirements. To this end, the present invention proposes a dual-frequency quadrifilar helical antenna that combines ultra-low profile and wide-angle radiation characteristics. It offers advantages such as an ultra-low profile, a wide axial ratio beam, and a wide half-power beam. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention discloses a dual-band four-arm helical antenna with both ultra-low profile and wide-angle radiation characteristics, comprising: a first annular dielectric substrate, a sickle-shaped radiating arm, an FPC dielectric substrate, a helical radiating arm, an annular support, a covering film, a floor, and a coaxial feed;

[0005] The inner wall of the first annular dielectric substrate is connected to the FPC dielectric substrate and is located directly above the FPC dielectric substrate;

[0006] There are four groups of sickle-shaped radiating arms, and every two groups are placed 90 degrees apart and placed on the first annular dielectric substrate. Each group of sickle-shaped radiating arms includes a long sickle-shaped radiating arm and a short sickle-shaped radiating arm.

[0007] The outer surface of the FPC dielectric substrate is tightly connected to the first annular dielectric substrate, and the inner wall is tightly connected to the annular support. The two ends of the FPC dielectric substrate are connected and surrounded by the outer surface of the annular support. The upper end of the FPC dielectric substrate is flush with the upper surface of the first annular dielectric substrate, and the lower end is flush with the floor.

[0008] The spiral radiating arms are closely attached to the outer surface of the FPC dielectric substrate. There are four groups of spiral radiating arms, and each two groups are placed 90 degrees apart. Each group includes a first spiral radiating arm, a second spiral radiating arm, a metal connecting strip, a ground patch, and a feed patch. The first spiral radiating arm is connected to the long sickle-shaped radiating arm, and the second spiral radiating arm is connected to the short sickle-shaped radiating arm.

[0009] The annular support includes a first annular support and a second annular support, wherein the outer surface of the first annular support is in close contact with the inner surface of the FPC dielectric substrate, and the upper surface of the first annular support is flush with the upper surface of the first annular dielectric substrate; the outer surface of the second annular support is in close contact with the inner surface of the FPC dielectric substrate, and the lower surface of the second annular support is flush with the floor;

[0010] The covering film is tightly attached to the outer surface of the spiral radiating arm, which can slow down the oxidation of the metal surface. A 2mm gap is retained at the top and bottom of the covering film to facilitate circuit connection.

[0011] Furthermore, by adopting the annular support and the first annular dielectric substrate, the shielding of the spiral radiating arm by the dielectric is significantly reduced, the radiation efficiency of the antenna is significantly improved, and the stability of the antenna is enhanced.

[0012] Furthermore, by providing the sickle-shaped radiating arm, the cross-section of the antenna can be significantly reduced and wide-angle radiation characteristics can be achieved. Accordingly, by providing the long sickle-shaped radiating arm, the low-frequency HPBW can be widened; by providing the short sickle-shaped radiating arm, the high-frequency HPBW can be widened.

[0013] Furthermore, under the premise of maintaining the advantage of small size, by increasing the distance between the first helical radiating arm and the second helical radiating arm, it can be ensured that the antenna has the characteristics of wide axial ratio beamwidth at dual frequency points.

[0014] Furthermore, the antenna can operate at dual frequencies by adjusting the lengths of the long sickle-shaped radiation arm and the short sickle-shaped radiation arm.

[0015] Furthermore, by adjusting the length ratios of the sickle-shaped radiation arm in the horizontal direction and the first spiral radiation arm and the second spiral radiation arm in the vertical direction, the height is minimized while ensuring a wide beam, thereby achieving an ultra-low profile.

[0016] Due to the adoption of the above technical solution, the present invention provides a dual-band four-arm helical antenna with both ultra-low profile and wide-angle radiation characteristics, which has the following advantages: (1) The antenna has a relatively wide 3-dB axial ratio beamwidth in the two frequency bands of Beidou navigation. Specifically, the 3-dB axial ratio beamwidth in each direction at the 1.207 GHz frequency point reaches more than 145°; and the 3-dB axial ratio beamwidth in each direction at the 1.561 GHz frequency point reaches more than 128°. (2) The antenna has a relatively wide half-power beamwidth in the two frequency bands of Beidou navigation. Specifically, the half-power beamwidth in each direction at the 1.207 GHz frequency point reaches more than 120°; and the half-power beamwidth in each direction at the 1.561 GHz frequency point reaches more than 112°. (3) The antenna has an ultra-low profile, with a height of only 14.2 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a 3D structural diagram of a dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics;

[0019] Figure 2 This is a horizontal structural exploded diagram of a dual-band quadrifilar helical antenna with both ultra-low profile and wide-angle radiation characteristics according to the present invention;

[0020] Figure 3 This is a 3D structural exploded diagram of a dual-band quadrifilar helical antenna with both ultra-low profile and wide-angle radiation characteristics according to the present invention;

[0021] Figure 4 This is a structural diagram of the vertical radiation arms of a dual-band four-arm helical antenna having both ultra-low profile and wide-angle radiation characteristics according to the present invention;

[0022] Figure 5 This is the S-parameter curve of a dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics according to the present invention;

[0023] Figure 6The graph shows the gain variation with frequency of a dual-frequency quadrifilar helical antenna having both ultra-low profile and wide-angle radiation characteristics according to the present invention.

[0024] Figure 7 This is a diagram of the axial ratio beamwidth at 1.207 GHz of a dual-band quadrifilar helical antenna having both ultra-low profile and wide-angle radiation characteristics according to the present invention;

[0025] Figure 8 This is a diagram of the axial ratio beamwidth at 1.561 GHz of a dual-band quadrifilar helical antenna having both ultra-low profile and wide-angle radiation characteristics according to the present invention;

[0026] Figure 9 This is a half-power beamwidth diagram of a dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics at 1.207 GHz;

[0027] Figure 10 This is a half-power beamwidth diagram of a dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics at 1.561 GHz.

[0028] In the figure: 1. First circular dielectric substrate, 2. Sickle-shaped radiation arm, 21. Long sickle-shaped radiation arm, 22. Short sickle-shaped radiation arm, 3. FPC dielectric substrate, 4. Spiral radiation arm, 41. First spiral radiation arm, 42. Second spiral radiation arm, 43. Metal connecting strip, 44. Ground patch, 45. Feed patch, 5. Circular support, 51. First circular support, 52. Second circular support, 6. Cover film, 7. Floor, 8. Coaxial feed. DETAILED DESCRIPTION

[0029] To make the technical solutions and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention:

[0030] like Figure 1 、 2 , 3, and 4 show a dual-band four-arm helical antenna with both ultra-low profile and wide-angle radiation characteristics, comprising: a first circular dielectric substrate 1, a sickle-shaped radiating arm 2, an FPC dielectric substrate 3, a helical radiating arm 4, a circular support 5, a covering film 6, a floor 7, and a coaxial feed 8.

[0031] The inner wall of the first annular dielectric substrate 1 is connected to the FPC dielectric substrate 3 and is located directly above the FPC dielectric substrate 3; there are 4 groups of sickle-shaped radiation arms 2, and each two groups are placed at 90° intervals, and are placed on the first annular dielectric substrate 1, and each group of sickle-shaped radiation arms 2 includes a long sickle-shaped radiation arm 21 and a short sickle-shaped radiation arm 22; the outer surface of the FPC dielectric substrate 3 is tightly connected to the first annular dielectric substrate 1, and the inner wall is tightly connected to the annular support 5, and the two ends of the FPC dielectric substrate 3 are connected and surrounded by the outer surface of the annular support 5, and the upper end of the FPC dielectric substrate 3 is flush with the upper surface of the first annular dielectric substrate 1, and the lower end is flush with the floor 7; the spiral radiation arm 4 is tightly attached to the outer surface of the FPC dielectric substrate 3, and there are 4 groups of spiral radiation arms 4, and each two groups are placed at 90° intervals, and each group includes a first spiral radiation Arm 41, second spiral radiating arm 42, metal connecting strip 43, ground patch 44 and feeding patch 45, the first spiral radiating arm 41 is connected to the long sickle-shaped radiating arm 21, and the second spiral radiating arm 42 is connected to the short sickle-shaped radiating arm 22; the annular support 5 includes a first annular support 51 and a second annular support 52, the outer surface of the first annular support 51 is tightly connected to the inner surface of the FPC dielectric substrate 3, and the upper surface of the first annular support 51 is flush with the upper surface of the first annular dielectric substrate 1; the outer surface of the second annular support 52 is tightly connected to the inner surface of the FPC dielectric substrate 3, and the lower surface of the second annular support 52 is flush with the floor 7; the covering film 6 is tightly attached to the outer surface of the spiral radiating arm 4, which can slow down the oxidation of the metal surface, and a 2mm gap is retained at the top and bottom ends of the covering film 6 to facilitate circuit connection.

[0032] The dual-band quadrifilar helical antenna, which combines ultra-low profile with wide-angle radiation characteristics, uses a three-dimensional helical structure to achieve both low profile and excellent radiation characteristics. By adopting a circular support 5 and a first circular dielectric substrate 1, the dielectric shielding of the spiral radiating arm 4 is significantly reduced, significantly improving the antenna's radiation efficiency while also enhancing the antenna's stability. By providing the sickle-shaped radiating arm 2, the antenna's profile can be significantly reduced and wide-angle radiation characteristics can be achieved. Accordingly, by providing the long sickle-shaped radiating arm 21, the low-frequency HPBW can be widened; by providing the short sickle-shaped radiating arm 22, the high-frequency HPBW can be widened. While maintaining the advantage of a small size, by increasing the spacing between the first helical radiating arm 41 and the second helical radiating arm 42, the antenna can ensure a wide axial ratio beamwidth at dual frequencies. The antenna can be operated in dual frequencies by adjusting the length of the long sickle-shaped radiating arm 21 and the short sickle-shaped radiating arm 22. By adjusting the length ratios of the sickle-shaped radiation arm 2 in the horizontal direction and the first spiral radiation arm 41 and the second spiral radiation arm 42 in the vertical direction, the height is minimized while ensuring a wide beam, thereby achieving an ultra-low profile.

[0033] The technical indicators adopted by the present invention are as follows:

[0034] Center frequency: 1.08GHz-1.42GHz and 1.48GHz-1.89GHz

[0035] Polarization mode: RHCP

[0036] Axial ratio bandwidth (AR<3): (1.11-1.26GHz) 12.7% and (1.43-1.71GHz) 17.8%

[0037] Gain: >3.8dBic

[0038] Axial beamwidth: >145° (1.207GHz) and >128° (1.561GHz)

[0039] Half-power beamwidth: >120° (1.207GHz) and >112° (1.561GHz)

[0040] Figure 5 The S-parameter curve of the dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics is shown in the figure. The results show that the frequency ranges in which the antenna return loss is greater than 10dB are 1.08-1.42GHz (27.2%) and 1.48-1.89GHz (24.3%).

[0041] Figure 6 This graph shows the gain versus frequency for a dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics. The results show that the antenna achieves a gain greater than 3.8dB between 1.15GHz and 1.3GHz, and greater than 5.1dB between 1.55GHz and 1.59GHz.

[0042] Figure 7 The following curves show the antenna's axial beamwidth at 1.207 GHz when phi is 0°, 45°, 90°, and 135°. The measured 3-dB axial beamwidth at 0° is 154°, at 45° is 160°, at 90° is 146°, and at 135° is 145°. This indicates that this antenna has a wide 3-dB axial beamwidth.

[0043] Figure 8 The following curves show the antenna's axial beamwidth at 1.561 GHz when phi is 0°, 45°, 90°, and 135°. The measured 3-dB axial beamwidth at 0° is 128°, at 45° is 129°, at 90° is 129°, and at 135° is 128°. This indicates that this antenna has a wide 3-dB axial beamwidth.

[0044] Figure 9 The following curves show the half-power beamwidth of the antenna at 1.207 GHz when phi is 0°, 45°, 90°, and 135°. The half-power beamwidth measured at 0° is 120°, at 45° is 124°, at 90° is 120°, and at 135° is 121°. The antenna gain is 4.1 dB at 1.207 GHz. This indicates that the antenna has a wide half-power beamwidth and achieves good gain at various elevation angles.

[0045] Figure 10 The following curves show the half-power beamwidth of the antenna at 1.561 GHz when phi is 0°, 45°, 90°, and 135°. The half-power beamwidth measured at 0° is 113°, at 45° is 112°, at 90° is 113°, and at 135° is 112°. The antenna gain is 5.1 dB at 1.561 GHz. This indicates that this antenna has a wide half-power beamwidth and achieves good gain at various elevation angles.

[0046] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics, characterized by include: A first annular dielectric substrate (1), a sickle-shaped radiating arm (2), an FPC dielectric substrate (3), a spiral radiating arm (4), an annular support (5), a covering film (6), a floor (7), and a coaxial feed (8); The inner wall of the first annular dielectric substrate (1) is connected to the FPC dielectric substrate (3) and is located directly above the FPC dielectric substrate (3); The sickle-shaped radiation arms (2) include four groups, with each two groups arranged at 90° intervals, and are placed on the first annular dielectric substrate (1), wherein each group of sickle-shaped radiation arms (2) includes a long sickle-shaped radiation arm (21) and a short sickle-shaped radiation arm (22); The outer surface of the FPC dielectric substrate (3) is tightly connected to the first annular dielectric substrate (1), and the inner wall is tightly connected to the annular support (5), and the two ends of the FPC dielectric substrate (3) are connected and surrounded by the outer surface of the annular support (5), and the upper end of the FPC dielectric substrate (3) is flush with the upper surface of the first annular dielectric substrate (1), and the lower end is flush with the floor (7); The spiral radiating arms (4) are tightly attached to the outer surface of the FPC dielectric substrate (3); the spiral radiating arms (4) include four groups, and each two groups are arranged at a 90° interval; each group of spiral radiating arms (4) includes a first spiral radiating arm (41), a second spiral radiating arm (42), a metal connecting strip (43), a ground patch (44) and a feeding patch (45); the first spiral radiating arm (41) is connected to the long sickle-shaped radiating arm (21), and the second spiral radiating arm (42) is connected to the short sickle-shaped radiating arm (22); The annular support (5) comprises a first annular support (51) and a second annular support (52), wherein the outer surface of the first annular support (51) is in close contact with the inner surface of the FPC dielectric substrate (3), and the upper surface of the first annular support (51) is flush with the upper surface of the first annular dielectric substrate (1); the outer surface of the second annular support (52) is in close contact with the inner surface of the FPC dielectric substrate (3), and the lower surface of the second annular support (52) is flush with the floor (7); The covering film (6) is tightly attached to the outer surface of the spiral radiating arm (4), thereby slowing down the oxidation of the metal surface, and a certain gap is retained at the top and bottom ends of the covering film (6).

2. The dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics according to claim 1, characterized in that: By adopting the annular support (5) and the first annular dielectric substrate (1), shielding of the spiral radiation arm (4) by the dielectric is reduced, thereby improving the radiation efficiency of the antenna and enhancing the stability of the antenna.

3. The dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics according to claim 1, characterized in that: The cross section of the antenna is reduced and wide-angle radiation characteristics are achieved by arranging the sickle-shaped radiation arm (2); the low-frequency HPBW is widened by arranging the long sickle-shaped radiation arm (21); and the high-frequency HPBW is widened by arranging the short sickle-shaped radiation arm (22).

4. The dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics according to claim 1, characterized in that: By increasing the distance between the first helical radiation arm (41) and the second helical radiation arm (42), it is ensured that the antenna has the characteristics of wide axial ratio beam width at dual frequency points.

5. The dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics according to claim 1, characterized in that: The antenna is made to operate in dual frequency bands by adjusting the lengths of the long sickle-shaped radiation arm (21) and the short sickle-shaped radiation arm (22).

6. The dual-band quadrifilar helical antenna with ultra-low profile and wide-angle radiation characteristics according to claim 1, characterized in that: By adjusting the length ratio of the sickle-shaped radiation arm (2) in the horizontal direction and the first spiral radiation arm (41) and the second spiral radiation arm (42) in the vertical direction, the height of the antenna is reduced while ensuring a wide beam, thereby achieving an ultra-low profile.

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