Dual-polarized probe antenna and design method thereof

Abstract

The application discloses a dual-polarized probe antenna and a design method thereof, and belongs to the field of wireless communication and microwave technology. The antenna is mainly composed of an electric dipole, a magnetic dipole and a coaxial cable. The coaxial cable is attached to the electric dipole, and is perpendicular to a ground plate; the inner arc side of the magnetic dipole is connected to the ground plate through a short circuit wall, forming a non-closed structure of inner arc short circuit and outer arc open circuit, and meanwhile, the magnetic dipole is parallel to the ground plate and perpendicular to the electric dipole, so as to generate a phase difference of 90 degrees between the two. The symmetry plane (equivalent electric wall) of the magnetic dipole and the symmetry plane (equivalent magnetic wall) of the electric dipole are in the same plane, and the layout makes the dual-polarized antenna have extremely high port isolation. The dual-polarized antenna has wide application prospects in fields such as vehicle-mounted, airborne and ship-mounted.

Description

Technical Field

[0001] This invention relates to a dual-polarized probe antenna and its design method, belonging to the field of wireless communication and microwave technology. Background Technology

[0002] To fully expand and enhance the capacity of wireless / mobile communication systems, the demand for dual-polarized antennas is increasing. Generally, using horizontal dipole antennas placed perpendicularly and co-located can achieve a port isolation of over 25 dB for dual-polarized antennas. For dual-polarized antennas using similar dipoles, the typical port isolation of their orthogonal polarization channels is usually in the range of 20-35 dB.

[0003] To further improve the cross-polarization discrimination rate and port isolation of antenna systems, especially to achieve multi-antenna coexistence under conditions of a large number of antennas and multiple frequency bands, it is necessary to further explore technologies to improve the port isolation of dual-polarized antennas. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a dual-polarized probe antenna and its design method. The highlight of this invention is that it uses positive cross-channel element antennas with complementary electrical characteristics, instead of the same type of element antenna, to construct the dual-polarized antenna. By making the equivalent virtual electric wall of the magnetic dipole and the equivalent virtual magnetic wall of the electric dipole lie in the same plane, a high isolation of 50dB (average value) or higher is achieved through the electromagnetic mismatch between the magnetic dipole and the electric dipole. This antenna has the advantages of simple structure, no need for external filtering / matching network, and low manufacturing cost.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A design method for a dual-polarized probe antenna, the design method specifically comprising:

[0007] Above the ground plane is a magnetic dipole consisting of a fan-shaped annular patch. The inner arc of the fan-shaped annular patch is connected to the ground plane through a short-circuit wall, forming a non-closed structure with the inner arc short-circuited and the outer arc open-circuited. The magnetic dipole is parallel to the ground plane, and the two are connected by a probe.

[0008] Above the ground plane, there is an electric dipole consisting of two identical fan-shaped patches, which is perpendicular to the ground plane.

[0009] Two coaxial cables are disposed on the surface of the electric dipole. One coaxial cable is used for power feeding and is called the power feeding cable. The other coaxial cable is not used for power feeding and is called the inactive cable. The outer conductor of the power feeding cable is attached to the right arm of the electric dipole, and the inner conductor is connected to the left arm of the electric dipole. The inactive cable is symmetrically attached to the left arm of the electric dipole and grounded to balance the current on the left and right arms of the electric dipole and achieve symmetrical power feeding.

[0010] The electric dipole and the magnetic dipole are placed at the same address, such that the equivalent virtual electric wall of the magnetic dipole and the equivalent virtual magnetic wall of the electric dipole are located in the same plane.

[0011] The resonant mode order of the electric dipole (2) and the magnetic dipole (5) can be independently adjusted and combined as needed.

[0012] Furthermore, the central axis of the electric dipole is perpendicular to the ground plane.

[0013] Furthermore, the inner conductor of the feed cable is connected to a straight side of the left arm of the electric dipole.

[0014] Furthermore, a pair of symmetrical tuning branches are provided on the electric dipole.

[0015] Furthermore, a pair of symmetrical tuning stubs are provided on the magnetic dipole.

[0016] Furthermore, the distance between the magnetic dipole and the ground plane is no greater than 0.25 times the wavelength.

[0017] Furthermore, the probe is a coaxial cable.

[0018] Furthermore, the port isolation of the antenna can be further adjusted by changing the degree of bending and diameter of the feed cable and the inactive cable, as well as the coupling distance between the electric dipole and the magnetic dipole.

[0019] A dual-polarized probe antenna is fabricated using the method described above.

[0020] Furthermore, the electric dipole is disposed on the side away from the outer arc of the magnetic dipole and close to the inner arc of the magnetic dipole.

[0021] Furthermore, the feed cable and the invalid cable are symmetrical about the center of the magnetic dipole.

[0022] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0023] This invention designs an electric dipole and a magnetic dipole to be perpendicular to each other and co-located, thus placing the equivalent virtual electric wall of the magnetic dipole and the equivalent virtual magnetic wall of the electric dipole on the same plane. The electromagnetic mismatch allows the antenna to achieve a high isolation of over 50 dB. This antenna features a simple structure and low manufacturing cost, and has broad application prospects in vehicle-mounted, airborne, and shipborne applications. Furthermore, due to its simple structure and high port isolation, this dual-polarized antenna can be used as a reference dual-polarized probe antenna in an antenna measurement system. Attached Figure Description

[0024] Figure 1 It is a three-dimensional schematic diagram of the antenna and a schematic diagram of its reference coordinates;

[0025] Figure 2 This is a schematic diagram of the front structure and reference coordinates of the antenna;

[0026] Figure 3 These are the antenna reflection coefficient characteristic diagram and isolation characteristic diagram obtained by calculation and actual measurement using HFSS software.

[0027] Wherein, 1 is the ground plane, 2 is the electric dipole, 3 and 3' are the tuning stubs of the electric dipole, 4 is the inactive cable, 4' is the feed cable, 5 is the magnetic dipole, 6 is the probe, 7 and 7' are the tuning stubs of the magnetic dipole, and 8 is the inner conductor of the feed cable. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0029] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings:

[0031] like Figure 1 , Figure 2 The dual-polarized probe antenna shown is obtained through the following design method:

[0032] An electric dipole 2 and a magnetic dipole 5 are disposed above a ground plane 1. The electric dipole 2 consists of two identical sector-shaped patches, and the magnetic dipole 5 consists of a sector-shaped annular patch. The inner arc edge of the magnetic dipole 5 is connected to the ground plane 1 through a short-circuit wall, forming a non-closed structure with an inner arc short circuit and an outer arc open circuit. The ground plane 1 and the magnetic dipole 5 are connected through a probe 6 (coaxial cable). A pair of coaxial cables are symmetrically bonded to the left and right arms of the electric dipole 2. The cable involved in power feeding is the power feeding cable 4', and the cable not involved in power feeding is the inactive cable 4. The outer conductor of the power feeding cable 4' is bonded to the right arm of the electric dipole 2, and the inner conductor 8 is connected to the left arm of the electric dipole 2. The inactive cable 4 is attached to the left arm of the electric dipole 2 and is perpendicularly connected to the ground plane 1. Electric dipole 2 and magnetic dipole 5 are placed at the same location, with magnetic dipole 5 parallel to ground plane 1 and perpendicular to electric dipole 2 (thus creating a 90° phase difference between them). This arrangement allows the equivalent virtual magnetic wall and equivalent virtual electric wall between the electric dipole and magnetic dipole to be located in the same plane. Through the mismatch between the electric dipole and magnetic dipole, the antenna achieves a high isolation of more than 50dB, realizing a dual-polarized antenna with high port isolation.

[0033] In this invention, changing the degree of bending, the diameter of the feed cable (4) and the inactive cable (4') attached inside the electric dipole, as well as the coupling distance between the electric dipole and the magnetic dipole, can further improve the port isolation of the antenna.

[0034] In one embodiment, the designed dual-polarized probe antenna uses air as the dielectric. The electric dipole has a radius of 26 mm, a central angle of 270°, and a tuning stub on the electric dipole with a length of 12 mm and a width of 8 mm. The magnetic dipole has an outer arc radius of 56 mm, an inner arc radius of 19.5 mm, a central angle of 210°, and a tuning stub on the magnetic dipole with a length of 22 mm and a width of 14 mm. The distance between the magnetic dipole and the ground plane is 5 mm. The electric and magnetic dipoles are co-located. The feed cable and the dead cable are symmetrical about the center of the magnetic dipole, with a distance of 8.8 mm from the center. The antenna characteristics are calculated using HFSS software simulation.

[0035] Figure 3The dashed line shows the measured antenna reflection coefficient characteristics of the magnetic dipole (antenna 1), whose impedance bandwidth covers the 2.24-2.56 GHz frequency band, with a center frequency of 2.4 GHz and a relative bandwidth of 13.3%. The dotted line shows the measured antenna reflection coefficient characteristics of the electric dipole (antenna 2), whose impedance bandwidth covers the 1.62-2.64 GHz frequency band and a relative bandwidth of approximately 42.5%. The short dashed line shows the antenna isolation characteristics calculated using HFSS software. The isolation of this antenna is above 60 dB within the frequency bands simultaneously covered by the impedance bandwidths of both the magnetic and electric dipoles. The solid line shows the measured antenna isolation characteristics. The isolation range of this antenna within the frequency bands simultaneously covered by the impedance bandwidths of both the magnetic and electric dipoles is approximately 44 dB-63 dB, with an average isolation value reaching 50 dB.

[0036] In summary, this invention discloses a dual-polarized probe antenna and its design method. A coaxial cable is connected to an electric dipole, making it perpendicular to the ground plane. The ground plane and the magnetic dipole are connected through a short-circuit wall, making them parallel. This ensures that the electric and magnetic dipoles are perpendicular to each other. At this point, the equivalent virtual magnetic wall of the electric dipole and the equivalent virtual electric wall of the magnetic dipole are in the same plane. The mismatch between them provides the antenna with high isolation. This invention features high isolation, simple structure, no need for external filtering / matching networks, and low manufacturing cost. It has broad application prospects in vehicle-mounted, airborne, and shipborne applications.

[0037] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any transformations or substitutions that can be conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A design method for a dual-polarized probe antenna, characterized in that, The design method is specifically as follows: Above the ground plane (1) is a magnetic dipole (5) consisting of a fan-shaped patch. The inner arc of the fan-shaped patch is connected to the ground plane (1) through a short-circuit wall, forming a non-closed structure with the inner arc short-circuited and the outer arc open. The magnetic dipole (5) is parallel to the ground plane (1), and the two are connected by a probe (6). Above the ground plane (1), there is also an electric dipole (2) consisting of two identical fan-shaped patches, which is perpendicular to the ground plane (1). Two coaxial cables are arranged on the surface of the electric dipole (2). One coaxial cable is used for power feeding and is called the power feeding cable (4'). The other coaxial cable is not used for power feeding and is called the inactive cable (4). The outer conductor of the power feeding cable (4') is attached to the right arm of the electric dipole (2), and the inner conductor is connected to the left arm of the electric dipole (2). The inactive cable (4) is symmetrically attached to the left arm of the electric dipole (2) and grounded to balance the current on the left and right arms of the electric dipole (2) and achieve symmetrical power feeding. By adopting a layout in which the electric dipole (2) and the magnetic dipole (5) are placed at the same address and the electric dipole is perpendicular to the magnetic dipole, the equivalent virtual electric wall of the magnetic dipole (5) and the equivalent virtual magnetic wall of the electric dipole (2) are located on the same plane, so as to improve the port isolation of the antenna. The electric dipole (2) is located on the side away from the outer arc of the magnetic dipole (5) and close to the inner arc of the magnetic dipole (5).

2. The design method of a dual-polarized probe antenna according to claim 1, characterized in that: The central axis of the electric dipole (2) is perpendicular to the ground plane (1).

3. The design method of a dual-polarized probe antenna according to claim 1, characterized in that: The inner conductor of the feed cable (4') is connected to a straight side of the left arm of the electric dipole (2).

4. The design method of a dual-polarized probe antenna according to claim 1, characterized in that: A pair of symmetrical tuning stubs are provided on the electric dipole (2) and / or the magnetic dipole (5).

5. The design method of a dual-polarized probe antenna according to claim 1, characterized in that: The resonant mode order of the electric dipole (2) and the magnetic dipole (5) can be independently controlled and combined as needed.

6. The design method of a dual-polarized probe antenna according to claim 1, characterized in that: The distance between the magnetic dipole (5) and the ground plane (1) is no greater than 0.25 times the wavelength.

7. The design method of a dual-polarized probe antenna according to claim 1, characterized in that: The port isolation of the antenna can be further adjusted by changing the degree of bending and the diameter of the feed cable (4) and the inactive cable (4') as well as the coupling distance between the electric dipole (2) and the magnetic dipole (5).

8. A dual-polarized probe antenna, characterized in that: It is prepared by the method described in any one of claims 1 to 7.

9. A dual-polarized probe antenna according to claim 8, characterized in that: The feed cable (4') and the invalid cable (4) are symmetrical about the center of the magnetic dipole (5).

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