Bidirectional inclined circularly polarized beam fan-shaped patch antenna and design method thereof

Abstract

The invention discloses a bidirectional inclined circularly polarized beam fan-shaped patch antenna and a design method thereof, and the method comprises the steps: determining a first odd order resonance mode which is used for representing the antenna base order resonance of an antenna working frequency band; determining whether a first odd order resonance mode exists on the fan-shaped patch structure, wherein the fan-shaped patch structure is an antenna radiation unit structure; if the first odd-order resonance mode exists on the fan-shaped patch structure, adjusting the arc length of an arc of the fan-shaped patch structure so as to form the first odd-order resonance mode on the fan-shaped patch structure; and determining patch surface current distribution of the fan-shaped patch structure in the first odd-order resonance mode, wherein the patch surface current distribution is used for determining an excitation position of an excitation signal of the first odd-order resonance mode.

Description

Technical Field

[0001] The invention relates to a bidirectional tilted circular polarization beam sector patch antenna and a design method thereof, belonging to the technical field of microwaves and antennas. Background Art

[0002] As the operating frequency of wireless communication systems becomes higher and higher, the operating frequency of antennas also increases, which makes antenna design and development more difficult. Compared with linearly polarized antennas, circularly polarized (CP) antennas are widely used in many wireless applications because they can effectively reduce multipath interference and polarization mismatch losses caused by misalignment. Among them, planar circularly polarized antennas, such as microstrip circularly polarized antennas, have attracted widespread attention because they can conform to the surface of the carrier. However, most of their radiation beams are end-fired, which is not suitable for some situations where the main radiation beam is required to form a certain angle with the antenna plane. With the development of wireless communication technology, there is an urgent need to manufacture bidirectional circularly polarized antennas with tilted beam radiation capabilities to improve the quality of multipath signal reception, especially in satellite, navigation, vehicle networking, and space / polarization diversity communication systems.

[0003] Bidirectional circularly polarized antennas can provide spatial / polarization diversity capabilities at the same time. Generally speaking, bidirectional circularly polarized antennas can be divided into five categories according to their implementation type: (1) disc-shaped monopole antenna; (2) non-uniform even-mode square ring antenna; (3) complementary dipole antenna; (4) aperture antenna; (5) dielectric resonant antenna. In addition, circularly polarized antennas with dual inductance and bidirectionality can also be realized through periodic structures or metasurfaces. However, the bidirectional circularly polarized antennas of these structures are relatively complex and have more design parameters. Therefore, how to design a bidirectional circularly polarized antenna with a minimal structure and fewer antenna parameters is a challenging problem. The existing technology has been able to solve the design of end-fire / back-fire bidirectional circularly polarized antennas, but cannot realize the design of bidirectional tilted beam circularly polarized antennas.

[0004] In view of this, it is necessary to propose a more simplified, efficient and flexible bidirectional tilted circularly polarized beam sector patch antenna and its design method to promote the widespread application of bidirectional tilted circularly polarized beam antenna technology in various communication systems and provide important support for the development of future wireless communication technology. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies in the prior art and to provide a bidirectional tilted circularly polarized beam fan-shaped patch antenna and a design method thereof. The antenna has a simple patch structure and clear mathematical principles, and can achieve the circularly polarized beam tilt capability in the yz plane of the azimuth plane.

[0006] The present invention adopts the following technical solutions to solve the above technical problems:

[0007] On the one hand, the present invention provides a design method for a bidirectional tilted circularly polarized beam sector patch antenna, the design method comprising:

[0008] Determining a first odd-order resonance mode, where the first odd-order resonance mode is used to characterize a fundamental-order resonance of the antenna in an operating frequency band of the antenna;

[0009] Determining whether a first odd-order resonant mode exists on the fan-shaped patch structure, where the fan-shaped patch structure is an antenna radiation unit structure;

[0010] If a first odd-order resonance mode exists on the fan-shaped patch structure, adjusting the arc length of the fan-shaped patch structure to form the first odd-order resonance mode on the fan-shaped patch structure;

[0011] Determining a patch surface current distribution of the fan-shaped patch structure in the first odd-order resonance mode, wherein the patch surface current distribution is used to determine an excitation position of an excitation signal of the first odd-order resonance mode;

[0012] Determining a grounding structure, wherein the grounding structure provides a physical ground for the excitation signal;

[0013] A short-circuit structure is determined, where the short-circuit structure is used to connect the radius end of the fan-shaped patch structure with the grounding structure.

[0014] On the other hand, the present invention provides a bidirectional tilted circularly polarized beam sector patch antenna, the antenna is obtained by the above-mentioned design method, comprising:

[0015] The fan-shaped patch structure is arranged above the ground structure and is parallel to the ground structure;

[0016] The fan-shaped patch structure is connected to the ground structure through the short-circuit structure;

[0017] The fan-shaped patch structure is used to form a first odd-order resonance mode, and the first odd-order resonance mode forms a current distribution on the patch surface;

[0018] The excitation signal is located on the angular bisector of the current distribution on the patch surface of the fan-shaped patch structure, and is connected to the fan-shaped patch structure and the ground structure.

[0019] The first odd-order resonance mode is used to characterize the antenna fundamental-order resonance in the antenna operating frequency band, and the length of the outer arc of the fan-shaped patch structure is one time the wavelength corresponding to the antenna fundamental-order resonance frequency.

[0020] An air medium is filled between the fan-shaped patch structure and the ground structure.

[0021] The distance between the excitation signal and the center of the fan-shaped patch structure is in the range of 0.24 to 0.82 times the radius of the fan-shaped patch structure.

[0022] The resonance mode adopted by the antenna is the first odd-order resonance mode (α is the central angle of the fan-shaped patch structure).

[0023] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0024] (1) The antenna has a bidirectional tilted circularly polarized beam in the elevation plane, that is, the optimal tilt angle of the circularly polarized beam appears in the yz plane with an azimuth angle of 90°, and the tilt angle of the circularly polarized beam is ±30°.

[0025] (2) The antenna adopts the fundamental resonant mode and has a very simple structure, which effectively reduces the structural complexity of the bidirectional circularly polarized antenna. At the same time, it has the advantages of low profile, good bidirectional circularly polarized radiation characteristics, easy processing and manufacturing, and convenient mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the implementation process of a design method for a bidirectional tilted circularly polarized beam fan-shaped patch antenna of the present invention.

[0027] Figure 2 It is a schematic diagram of the top view structure and the reference coordinate system of Embodiment 1 of the bidirectional tilted circularly polarized beam sector patch antenna of the present invention;

[0028] Figure 3 3D schematic diagram and reference coordinate system of bidirectional tilted circularly polarized beam sector patch antenna embodiment 1 of the present invention; Figures 2 to 3 In the figure, 1 is a fan-shaped patch structure, 2 is a grounding structure, 3 is a short-circuit structure, and 4 is an excitation signal.

[0029] Figure 4 is the reflection coefficient (S11) of embodiment 1 of the bidirectional tilted circularly polarized beam sector patch antenna of the present invention;

[0030] Figure 5 It is the radiation pattern of the bidirectional tilted circularly polarized beam sector patch antenna embodiment 1 of the present invention in the yz plane;

[0031] Figure 6 is the axial ratio frequency response of the bidirectional tilted circularly polarized beam sector patch antenna embodiment 1 of the present invention at different elevation angles in the yz plane;

[0032] Figure 7 It is the gain and efficiency of embodiment 1 of the bidirectional tilted circularly polarized beam fan-shaped patch antenna of the present invention. DETAILED DESCRIPTION

[0033] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown 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 cannot be interpreted as limiting the present invention.

[0034] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0035] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0036] Figure 1 FIG. 1 is a flow chart of the antenna design method of the present invention. Figure 1 As shown, the method includes:

[0037] Determine a first odd-order resonance mode, where the first odd-order resonance mode is used to characterize the antenna fundamental-order resonance in the antenna operating frequency band. When designing an antenna, different antenna design requirements require different resonances. Therefore, the first odd-order resonance mode implemented on the antenna can be determined based on the antenna design requirements.

[0038] Determine whether there is a first odd-order resonance mode on the fan-shaped patch structure, where the fan-shaped patch structure is an antenna radiation unit structure; if there is a first odd-order resonance mode on the fan-shaped patch structure, adjust the arc length of the fan-shaped patch structure to form the first odd-order resonance mode on the fan-shaped patch structure; when designing the antenna, after determining the first odd-order resonance mode, determine the center angle of the fan-shaped patch structure according to the order of the resonance mode; and determine the radius of the fan-shaped patch structure according to the operating frequency band of the antenna.

[0039] Determine the patch surface current distribution of the fan-shaped patch structure in the first odd-order resonance mode, and the patch surface current distribution is used to determine the excitation position of the excitation signal of the first odd-order resonance mode; determine the grounding structure, and the grounding structure provides physical grounding for the excitation signal; determine the short-circuit structure, and the short-circuit structure is used to connect the radius end of the fan-shaped patch structure to the grounding structure.

[0040] like Figure 2 and Figure 3As shown, the present invention provides a bidirectional tilted circularly polarized beam sector patch antenna and a design method thereof, comprising a sector patch structure 1, a grounding structure 2, a short circuit structure 3 and an excitation signal 4; the sector patch structure constituting the antenna is a semi-closed structure, consisting of a sector patch structure 1, a grounding structure 2 and two radius long short circuit structures 3.

[0041] The fan-shaped patch structure 1 is located above the ground structure 2 and is parallel to the ground structure 2. The fan-shaped patch structure 1 is connected to the ground structure 2 via two short-circuit structures 3 with long radii. The excitation signal 4 is located on the angular bisector of the fan-shaped patch structure.

[0042] The length of the outer arc of the fan-shaped patch structure 1 is one time the wavelength corresponding to the fundamental resonant frequency of the antenna. The air medium is filled between the fan-shaped patch structure 1 and the grounding structure 2. The distance between the excitation signal 4 and the center of the fan-shaped patch structure 1 ranges from 0.24 to 0.82 times the radius of the fan-shaped patch structure 1. The resonant mode adopted by the antenna is the fundamental resonant mode, and its resonant mode is controlled by the radius and the outer arc length of the fan-shaped patch structure. It has a bidirectional tilted circularly polarized beam in the pitch plane. The optimal tilt angle of the circularly polarized beam appears on the yoz plane with an azimuth angle of 90°, and the tilt angle of the circularly polarized beam is ±30°.

[0043] Compared with conventional circularly polarized antennas, the bidirectional tilted circularly polarized beam sector patch antenna design method of the present invention adopts a novel sector patch structure, and circular polarization is achieved by the equal amplitude and orthogonal phase relationship of the electric field components radiated by the fundamental resonant mode of the antenna on the pitch plane. The antenna has a simple structure and is easy to design. The resonant frequency and the tilt angle of the circularly polarized beam are adjusted by correcting the arc length of the sector patch structure and the position of the excitation signal, thereby meeting the setting requirements of the wireless system.

[0044] Embodiment 1:

[0045] The antenna of this embodiment uses air as a dielectric medium (dielectric constant is 1), the distance between the fan-shaped patch structure 1 and the ground structure 2 is 5 mm, the radius of the fan-shaped patch structure is 33 mm, the center angle of the fan-shaped patch structure is 180°, the radius of the ground structure is 70 mm, the distance between the excitation signal and the center of the circle is 15 mm, and the size radius of the excitation signal is 0.65 mm.

[0046] Compare with Figure 4 , Figure 4 The reflection coefficient S of the antenna in Example 1 is given as 11 .Depend on Figure 4 It can be seen that the working frequency range of the antenna (S 11 >-10dB) is 2.29~2.62GHz, and the relative bandwidth reaches 13.5%. It can be seen that the antenna has a wide bandwidth under single-mode resonance conditions, covering the WLAN frequency band (2.4~2.484GHz).

[0047] Compare with Figure 5 , Figure 5 The yz plane radiation pattern of the antenna of Example 1 at 2.44 GHz is given. Figure 5 It can be seen that the antenna exhibits a bidirectional tilted circular polarization beam on the yz plane, the solid line is right-hand circular polarization, the dotted line is left-hand circular polarization, and the beam tilt angles are ±30° respectively.

[0048] Compare with Figure 6 , Figure 6 The axial ratio frequency response of the antenna of Example 1 at different elevation angles in the yz plane is given. Figure 6 It can be seen that within the entire antenna operating frequency range, the antenna has an axial ratio bandwidth of less than 3dB at an angle (90° in azimuth and ±30° in elevation).

[0049] Compare with Figure 7 , Figure 7 The antenna radiation efficiency and radiation gain of Example 1 in the direction of azimuth angle of 90° and elevation angle of plus or minus 30° are given. Figure 7 It can be seen that within the operating frequency range, the radiation gain of the antenna is greater than 3.75dBi, the average radiation gain is 4.05 / 4.07dB, and the average efficiency is 96.9%.

[0050] To summarize, the bidirectional tilted circularly polarized beam fan-shaped patch antenna designed in the present invention can obtain good circularly polarized beam tilt capability for different operating frequency bands of wireless communication systems by simply adjusting the central angle and arc length of the fan-shaped patch structure and the position of the excitation signal, thereby achieving flexible universality and good compatibility in antenna design and application.

[0051] The above description is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technology can understand and think of any changes or substitutions within the technical scope disclosed by the present invention, which should be included in the scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A design method for a bidirectional tilted circularly polarized beam sector patch antenna, characterized in that: include: Determining a first odd-order resonance mode, where the first odd-order resonance mode is used to characterize a fundamental-order resonance of the antenna in an operating frequency band of the antenna; Determining whether a first odd-order resonant mode exists on the fan-shaped patch structure, where the fan-shaped patch structure is an antenna radiation unit structure; If a first odd-order resonance mode exists on the fan-shaped patch structure, adjusting the arc length of the fan-shaped patch structure to form the first odd-order resonance mode on the fan-shaped patch structure; Determining a patch surface current distribution of the fan-shaped patch structure in the first odd-order resonance mode, wherein the patch surface current distribution is used to determine an excitation position of an excitation signal of the first odd-order resonance mode; Determining a grounding structure, wherein the grounding structure provides a physical ground for the excitation signal; A short-circuit structure is determined, where the short-circuit structure is used to connect the radius end of the fan-shaped patch structure with the grounding structure.

2. A bidirectional tilted circularly polarized beam sector patch antenna, characterized in that: include: The fan-shaped patch structure is arranged above the ground structure and is parallel to the ground structure; The fan-shaped patch structure is connected to the ground structure through the short-circuit structure; The fan-shaped patch structure is used to form a first odd-order resonance mode, and the first odd-order resonance mode forms a current distribution on the patch surface; The excitation signal is located on the angular bisector of the current distribution on the patch surface of the fan-shaped patch structure, and is connected to the fan-shaped patch structure and the ground structure.

3. A bidirectional tilted circularly polarized beam fan-shaped patch antenna as described in claim 2, characterized in that: the first odd-order resonance mode is used to characterize the antenna fundamental-order resonance of the antenna working frequency band, and the length of the circular arc of the fan-shaped patch structure is twice the wavelength corresponding to the antenna fundamental-order resonance frequency.

4. A bidirectional tilted circularly polarized beam sector patch antenna as described in claim 2, characterized in that: an air medium is filled between the sector patch structure and the ground structure.

5. A bidirectional tilted circularly polarized beam sector patch antenna as described in claim 2, characterized in that: the distance between the excitation signal and the center of the sector patch structure ranges from 0.24 to 0.82 times the radius of the sector patch structure.

6. The method according to claim 1, wherein the resonance mode adopted by the antenna is the first odd-order resonance mode. (α is the central angle of the fan-shaped patch structure).

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