A four-arm helical antenna

Abstract

The utility model discloses a four -armed helical antenna, include: antenna outer cover, the top of antenna outer cover is equipped with the flow cone surface or chamfer surface, the inner wall of antenna outer cover is inlayed and is equipped with the circuit board, and the outer wall of circuit board is plated and is equipped with the feed circuit, the outer wall of antenna outer cover respectively inserts and is equipped with first upper radiation branch, first lower radiation branch, second upper radiation branch and second lower radiation branch, and first upper radiation branch, first lower radiation branch, second upper radiation branch and second lower radiation branch are symmetric or rotation symmetry distribution setting. Can realize the omni -directional radiation of less than 1dB in the horizontal plane, and provide greater than 90's beam width in the vertical plane, combine the excellent axial ratio of less than 1.2dB in the range of pitch angle 80, make aircraft still can steady reception high low elevation angle satellite signal under the attitude such as roll, through the flexible design of branch path, can support right -hand circular polarization and left -hand circular polarization, vertical and horizontal polarization and a variety of ways.

Description

Technical Field

[0001] This utility model belongs to the field of antenna technology, specifically a four-arm spiral antenna. Background Technology

[0002] Satellite navigation and positioning systems for aircraft (such as drones and missiles) typically employ omnidirectional circularly polarized antennas to receive signals. These antennas must meet several core requirements: first, they must cover a large spatial area to ensure reception of satellite signals from all directions in the sky; second, they must have a low profile and conformal design to meet the aerodynamic and stealth design requirements of the aircraft; and third, the antenna must maintain stable reception of satellite signals and good circular polarization characteristics even when the aircraft undergoes various attitude changes during flight, including tumbling and rotation.

[0003] Currently, the technical solutions that meet some of the above requirements have the following limitations and disadvantages:

[0004] First, traditional quad-helical antennas typically consist of four radiating arms and a complex feeding network (such as using three bridges or distributed parameter circuits) to generate the required 90° phase difference. This approach has significant drawbacks: firstly, its feeding network structure is complex, occupies a large space, and is costly; secondly, its radiation pattern is usually hemispherical (approximately 180° range) in the vertical plane, making it easy for the aircraft to fall outside the effective coverage area of ​​the antenna when it pitches or rolls at large angles, resulting in signal interruption and making it impossible to achieve continuous positioning across all attitudes.

[0005] Second, the four-arm spiral antenna without a feed network uses a central metal support that also serves as the transmission line, with spiral radiating arms wrapped around the outside. Although it achieves circular polarization omnidirectional radiation, the central support is a necessary component, making it difficult to reduce the overall physical height (profile) of the antenna. This results in a complex structure, high manufacturing costs, and an inability to meet the requirements of modern aircraft for low profile, lightweight, and integration.

[0006] Third, low-profile planar circularly polarized antennas (such as microstrip patch antennas) have the advantages of low profile and easy conformal design. However, their inherent disadvantages are limited radiation pattern coverage, narrow vertical beamwidth, and hemispherical coverage characteristics. This means that their performance is highly dependent on the antenna's orientation; once the antenna plane rotates relative to the ground plane, its beam pointing towards the sky will deviate, causing signal attenuation or even loss. In addition, such antennas require a strict clearance area in their normal direction, prohibiting the placement of any metal components or circuit modules, which severely limits the utilization of space inside the aircraft and the design of multi-system integration. Utility Model Content

[0007] The technical solution adopted in this utility model is as follows: A four-arm helical antenna, comprising:

[0008] Antenna housing;

[0009] The top of the antenna radome is provided with a flow-guiding cone surface or a chamfered surface;

[0010] The inner wall of the antenna radome is fitted with a circuit board, and the outer wall of the circuit board is plated with a feeding circuit.

[0011] The outer wall of the antenna cover is respectively provided with a first upper radiating arm, a first lower radiating arm, a second upper radiating arm and a second lower radiating arm, and the first upper radiating arm, the first lower radiating arm, the second upper radiating arm and the second lower radiating arm are arranged symmetrically or rotationally symmetrically.

[0012] The first upper radiating arm and the first lower radiating arm are configured as the first radiating unit;

[0013] The second upper radiating arm and the second lower radiating arm are configured as the second radiating unit;

[0014] One end of the first upper radial support arm, the first lower radial support arm, the second upper radial support arm, and the second lower radial support arm are all electrically connected to the circuit board.

[0015] Furthermore, the ends of both the first and second upper radial arms that are furthest from the circuit board extend upward in a clockwise or counterclockwise direction.

[0016] Furthermore, the ends of both the first and second lower radial arms that are furthest from the circuit board are spirally extended downwards.

[0017] Furthermore, the cross-sections of the first upper radial arm, the first lower radial arm, the second upper radial arm, and the second lower radial arm are circular or rectangular.

[0018] Furthermore, the power supply circuit consists of either a T-shaped power divider or a Wilkins power divider.

[0019] Furthermore, one of the output terminals of the T-shaped power divider or Wilkins power divider is signal-connected to the first radiating unit.

[0020] Furthermore, the remaining output terminal of the T-shaped power divider or Wilkins power divider is signal-connected to the second radiating unit.

[0021] Furthermore, the antenna radome is made of a wave-transparent material, the diameter of the antenna radome is variable, and the cross-section of the antenna radome includes, but is not limited to, conical and cylindrical shapes.

[0022] Furthermore, the first and second radiating elements work together to realize a right-hand circularly polarized antenna or a left-hand circularly polarized antenna.

[0023] Furthermore, when the first upper radiating arm and the second upper radiating arm extend upward clockwise, right-hand circular polarization is achieved; when the first upper radiating arm and the second upper radiating arm extend upward counterclockwise, left-hand circular polarization is achieved.

[0024] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0025] (1) In this utility model, the four-arm spiral antenna can achieve omnidirectional radiation with uniform height in the horizontal plane, and its horizontal plane radiation pattern non-circularity is less than 1dB, ensuring that the antenna gain remains stable during the rotation or attitude change of the aircraft, and can continuously and reliably receive satellite signals from all directions, thus solving the signal interruption problem caused by the radiation pattern defects of traditional antennas.

[0026] (2) In this utility model, the antenna has a beamwidth of 3dB greater than 90° in the vertical plane and good signal coverage near the zenith direction (normal direction). At the same time, it can effectively cover the low elevation angle area and has excellent axial ratio performance (less than 1.2dB) within the 80° elevation angle range. This is significantly better than the traditional satellite receiving antenna with a low elevation angle axial ratio of greater than 4-5dB. Thus, it can simultaneously and stably receive satellite signals at high and low elevation angles and adapt to the complex and ever-changing flight attitude of the aircraft.

[0027] (3) In this utility model, by flexibly designing the extension paths and spatial distribution of the first upper radiating arm, the first lower radiating arm, the second upper radiating arm and the second lower radiating arm, the antenna can easily realize multiple polarization modes such as right-hand circular polarization, left-hand circular polarization, vertical polarization or horizontal polarization, meet the specific requirements of different communication systems for polarization modes, and broaden the versatility and application range of the antenna.

[0028] (4) In this utility model, the antenna adopts a feeding circuit composed of a T-shaped power divider or a Wilkins power divider, which eliminates the need for a traditional 90° or 180° phase difference feeding network, simplifies the feeding structure, significantly reduces the complexity and manufacturing cost of the antenna, and improves the reliability and consistency of the system.

[0029] (5) In this utility model, since the radiating arms are distributed on the outer surface of the antenna cover and the power supply network occupies a small space, the area inside the antenna, the area above and below the circuit board can be freed up and used to integrate and install other communication or electronic functional modules, realizing a high-density conformal design of multiple systems, effectively improving the space utilization and overall performance of the equipment.

[0030] (6) In this utility model, the antenna radiating arm can be designed conformally with the antenna cover, without the need for additional metal brackets. This not only reduces the number of parts and assembly costs, but also enables the antenna to flexibly adapt to various streamlined shapes such as cylindrical, conical and combined shapes, meeting the stringent requirements of modern aircraft for aerodynamics, stealth characteristics and equipment integration. Attached Figure Description

[0031] Figure 1 This is a perspective view of the present utility model;

[0032] Figure 2 This is a partial half-sectional view of the present invention;

[0033] Figure 3 This is a perspective view of the circuit board of this utility model;

[0034] Figure 4 This is a perspective view of the second lower radial support arm of this utility model;

[0035] Figure 5 This is a schematic diagram of the chamfered surface of this utility model;

[0036] Figure 6 This is a schematic diagram of the signal strength test data in the vertical plane direction of this utility model;

[0037] Figure 7 This is a schematic diagram of the horizontal plane direction signal strength test data of this utility model;

[0038] Figure 8 This is a schematic diagram of the axial ratio direction signal strength test data of this utility model.

[0039] The markings in the diagram are: 1. Antenna cover; 2. Circuit board; 3. First upper radiating arm; 4. First lower radiating arm; 5. Second upper radiating arm; 6. Second lower radiating arm; 101. Guide cone surface; 102. Chamfered surface; 201. Feed circuit. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0041] Example 1

[0042] Reference Figure 1 - Figure 8A four-arm helical antenna includes: an antenna shroud 1, the top of which has a guide cone surface 101 or a chamfered surface 102 to improve aerodynamic performance and enhance structural strength; a circuit board 2 embedded in the inner wall of the antenna shroud 1; a feed circuit 201 plated on the outer wall of the circuit board 2 for signal distribution and transmission; and a first upper radiating arm 3, a first lower radiating arm 4, a second upper radiating arm 5, and a second lower radiating arm 6 respectively inserted into the outer wall of the antenna shroud 1. Arm 4, the second upper radiating arm 5, and the second lower radiating arm 6 are arranged symmetrically or rotationally symmetrically to ensure the uniformity and polarization characteristics of the radiation field. The first upper radiating arm 3 and the first lower radiating arm 4 together constitute the first radiation unit, and the second upper radiating arm 5 and the second lower radiating arm 6 together constitute the second radiation unit. One end of the first upper radiating arm 3, the first lower radiating arm 4, the second upper radiating arm 5, and the second lower radiating arm 6 are all electrically connected to the feed circuit 201 on the circuit board 2 to ensure effective signal feed.

[0043] Reference Figures 1-8 The ends of the first upper radiating arm 3 and the second upper radiating arm 5 that are away from the circuit board 2 both extend upward in a clockwise or counterclockwise direction to form an upward radiating structure. The ends of the first lower radiating arm 4 and the second lower radiating arm 6 that are away from the circuit board 2 both extend downward in a spiral direction to form a downward radiating structure. The cross-sections of the first upper radiating arm 3, the first lower radiating arm 4, the second upper radiating arm 5, and the second lower radiating arm 6 can be circular or rectangular, depending on the mechanical strength, frequency characteristics, and process requirements.

[0044] Reference Figures 1-8 The feed circuit 201 consists of either a T-shaped power divider or a Wilkins power divider. One output terminal of the T-shaped power divider or the Wilkins power divider is connected to the first radiating element, and the other output terminal is connected to the second radiating element. The two output terminals are in phase, eliminating the need for complex 90° or 180° phase difference networks. This design is simple, low-cost, and easy to integrate. The antenna radome 1 is made of a wave-transparent material, such as plastic or composite material, to ensure effective electromagnetic wave penetration. The first upper radiating arm 3 and the second upper radiating arm 5 extend upwards clockwise... When extended, right-hand circular polarization is achieved. When the first upper radiating arm 3 and the second upper radiating arm 5 extend upward counterclockwise, left-hand circular polarization is achieved. Vertical or horizontal polarization can also be achieved by adjusting the arm path. The polarization mode is flexible and adjustable. In addition, the shape of the antenna cover 1 can be cylindrical, conical or a combination thereof, and the size can be adjusted as needed. The radiating arms can be designed conformally with the cover, without the need for additional brackets, and are suitable for various installation environments. The radiating arms can also be printed on the flexible circuit board 2 and rolled into the required shape, further expanding the application scenarios and integration capabilities of the antenna.

[0045] The following describes in detail the usage method of a four-arm spiral antenna provided by this utility model embodiment. The usage method includes the following steps: The signal is first input to the feed circuit 201 set on the circuit board 2. The feed circuit 201 is implemented by a T-shaped power divider or a Wilkins power divider. Its function is to split the input signal into two equal-amplitude and in-phase signals. One signal is fed into the first radiating element (i.e., the first upper radiating arm 3 and the first lower radiating arm 4) through one output terminal of the feed circuit 201, and the other signal is fed into the second radiating element (i.e., the second upper radiating arm 5 and the second lower radiating arm 6) through the other output terminal of the feed circuit 201. The first upper radiating arm 3 and the second upper radiating arm 5 both extend spirally upward, and the first lower radiating arm 4 and the second lower radiating arm 6 both extend spirally downward. Since the first radiating element and the second radiating element are symmetrically or rotationally symmetrically distributed, and each arm... The specific extension paths of the arms (e.g., the first upper radiating arm 3 extends to the upper right and the first lower radiating arm 4 extends to the lower left) enable the electromagnetic waves excited by the four arms to synthesize circularly polarized waves in space. By designing the extension direction of the arms, right-hand circular polarization, left-hand circular polarization, vertical polarization, or horizontal polarization can be achieved respectively. The electromagnetic waves radiated by the antenna can propagate outward through the antenna radome 1 made of wave-transparent material. Due to the symmetrical distribution of the radiating elements and the upward and downward extension of the radiating arms respectively, the antenna forms omnidirectional radiation in the horizontal plane and the beamwidth in the vertical plane is greater than 90°. Thus, it can still stably receive high and low elevation angle satellite signals when the attitude of the aircraft changes. In addition, because the feed network structure is simple and the radiating arms are distributed on the surface of the antenna radome 1, the space inside the antenna radome 1 and above and below the circuit board 2 is not blocked by the radiator, and other communication or electronic modules can be installed to achieve conformal design and high-density integration of multiple systems.

[0046] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A four-arm helical antenna, characterized by, include: Antenna cover (1); The top of the antenna cover (1) is provided with a flow-guiding cone surface (101) or a chamfered surface (102); The inner wall of the antenna cover (1) is embedded with a circuit board (2), and the outer wall of the circuit board (2) is plated with a feed circuit (201); The outer wall of the antenna cover (1) is respectively provided with a first upper radiating arm (3), a first lower radiating arm (4), a second upper radiating arm (5) and a second lower radiating arm (6), and the first upper radiating arm (3), the first lower radiating arm (4), the second upper radiating arm (5) and the second lower radiating arm (6) are arranged symmetrically or rotationally symmetrically. The first upper radiating arm (3) and the first lower radiating arm (4) are set as the first radiating unit; The second upper radiating arm (5) and the second lower radiating arm (6) are configured as the second radiating unit; One end of the first upper radial support arm (3), the first lower radial support arm (4), the second upper radial support arm (5), and the second lower radial support arm (6) are all electrically connected to the circuit board (2).

2. A quadrifilar helical antenna as claimed in claim 1, characterized in that: The ends of the first upper radial support arm (3) and the second upper radial support arm (5) that are away from the circuit board (2) both extend upward in a clockwise or counterclockwise direction.

3. A quadrifilar helical antenna as claimed in claim 2, characterized in that: The ends of the first lower radial support arm (4) and the second lower radial support arm (6) that are away from the circuit board (2) are both spirally extended downwards.

4. A quadrifilar helical antenna as claimed in claim 3, characterized in that: The cross-sections of the first upper radial arm (3), the first lower radial arm (4), the second upper radial arm (5), and the second lower radial arm (6) are circular or rectangular.

5. A quadrifilar helical antenna as claimed in claim 4, characterized in that: The antenna cover (1) is made of a wave-transparent material, the diameter of the antenna cover (1) is variable, and the cross-section of the antenna cover (1) includes, but is not limited to, conical and cylindrical shapes.

6. A quadrifilar helical antenna as claimed in claim 5, characterized in that: The first and second radiating elements work together to realize a right-hand circularly polarized antenna or a left-hand circularly polarized antenna.

7. A four-arm spiral antenna as described in claim 6, characterized in that: When the first upper radial arm (3) and the second upper radial arm (5) extend upward in a clockwise direction, right-hand circular polarization is achieved; When the first upper radial arm (3) and the second upper radial arm (5) extend upward in a counterclockwise direction, left-hand circular polarization is achieved.

Images