Continuous two-dimensional beam frequency scanning circularly polarized antenna and design method thereof

Abstract

The invention discloses a continuous two-dimensional beam frequency scanning circularly polarized antenna and a design method thereof, and the method comprises the steps: determining a first high-order resonance mode which is used for representing the first resonance of an antenna working frequency band; determining whether a first high-order resonance mode exists on the sector-ring-shaped patch structure or not, wherein the sector-ring-shaped patch structure is an antenna radiation unit structure; and if the first high-order resonance mode exists on the sector-ring-shaped patch structure, adjusting the arc length of the outer arc of the sector-ring-shaped patch structure and the ratio of the arc length of the inner arc to the arc length of the outer arc of the sector-ring-shaped patch structure so as to form the first high-order resonance mode on the sector-ring-shaped patch structure.

Description

Technical Field

[0001] The invention relates to a continuous two-dimensional beam frequency scanning circular polarization antenna and a design method thereof, belongs to the technical field of microwaves and antennas, and is mainly used in a communication-sensing integrated wireless system. Background Art

[0002] With the rapid development of communication systems such as mobile communications, satellite communications, and vehicle communications, higher requirements are placed on the beam scanning performance of antennas. Compared with linearly polarized antennas, circularly polarized (CP) antennas are widely used in many wireless communication systems because they can effectively reduce multipath interference and polarization mismatch losses caused by misalignment. Therefore, the realization of two-dimensional circularly polarized beam scanning antennas has very important application value in modern communication technology. At present, two-dimensional beam scanning antennas are mainly realized based on mechanical scanning, phased arrays, reflect arrays, metasurfaces, etc. Mechanical scanning realizes the change of antenna pointing through mechanical devices, but its response speed is slow and is not suitable for rapidly changing communication environments. Phased array antennas realize beam scanning by controlling the phase of each array unit. They have fast response speed and flexible beam control capabilities, but their complex hardware structure and high cost limit their promotion in large-scale applications. Reflectarray antennas use reflective surfaces to control the direction of the beam and have high directivity and beam control capabilities, but they have complex structures, high manufacturing costs, and are limited by size and weight, such as the invention named "A Ka-band two-dimensional beam scanning folded reflectarray antenna based on liquid crystal". Metasurface antennas use artificially designed periodic structures to control the beam and have small size and weight, but they still face challenges in manufacturing difficulty and broadband design in engineering practice, such as the invention named "A two-dimensional multi-beam metasurface antenna with wideband and large angle scanning". Although the two-dimensional beam scanning antennas implemented in the above manner have achieved certain success in providing beam control capabilities, they also have disadvantages such as complex structure, large size, high cost, and limited design methods, which limit their application in certain fields.

[0003] In view of this, it is necessary to propose a more simplified, efficient and flexible design method for continuous two-dimensional beam frequency scanning circularly polarized antenna to promote the widespread application of two-dimensional beam frequency scanning circularly polarized antenna technology in various communication systems and provide important support for the development of future wireless communication technology. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies in the prior art and to provide a continuous two-dimensional beam frequency scanning circularly polarized antenna and a design method thereof. The antenna has a simple patch structure and clear mathematical principles, and can achieve continuous two-dimensional beam frequency scanning capabilities of 250° in azimuth and 45° in elevation.

[0005] The present invention adopts the following technical solutions to solve the above technical problems:

[0006] In one aspect, the present invention provides a design method for a continuous two-dimensional beam frequency scanning circularly polarized antenna, the design method comprising:

[0007] Determining a first high-order resonance mode, where the first high-order resonance mode is used to characterize a first resonance in an operating frequency band of the antenna;

[0008] Determine whether there is a first high-order resonant mode on the fan-shaped ring patch structure, where the fan-shaped ring patch structure is an antenna radiation unit structure;

[0009] If a first high-order resonant mode exists on the fan-shaped patch structure, the outer arc length and the ratio of the inner and outer arc lengths of the fan-shaped patch structure are adjusted to form the first high-order resonant mode on the fan-shaped patch structure.

[0010] Determining a second higher-order resonance mode, where the second higher-order resonance mode is used to characterize a second resonance in an operating frequency band of the antenna;

[0011] Determine whether there is a second high-order resonant mode on the fan-ring patch structure. If there is a second high-order resonant mode on the fan-ring patch structure, adjust the outer arc length and the ratio of the inner and outer arc lengths of the fan-ring patch structure to form a second high-order resonant mode on the fan-ring patch structure.

[0012] Determine the patch surface current distribution of the fan-shaped patch structure in the second high-order resonance mode, wherein the patch surface current distribution is used to determine the disturbance position of the disturbance structure in the second high-order resonance mode;

[0013] Determine the patch surface current distribution of the fan-shaped ring patch structure in the first odd-order resonance mode, wherein the patch surface current distribution is used to determine the excitation position of the excitation signal of the fan-shaped ring patch structure;

[0014] Determining a grounding structure, wherein the grounding structure provides a physical ground for the excitation signal;

[0015] A short-circuit structure is determined, where the short-circuit structure is used to connect the radius end and the inner arc end of the fan-shaped patch structure with the grounding structure.

[0016] On the other hand, the present invention provides a continuous two-dimensional beam frequency scanning circularly polarized antenna, the antenna is obtained by the above-mentioned design method, comprising:

[0017] The fan-shaped patch structure is arranged above the ground structure and is parallel to the ground structure;

[0018] The fan-shaped patch structure is connected to the ground structure through the short-circuit structure;

[0019] The fan-shaped patch structure and the disturbance structure are used to form a first high-order resonance mode and a second high-order resonance mode;

[0020] 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 grounding structure.

[0021] The first high-order resonance mode is used to characterize a first resonance in the working frequency band of the antenna, and the second high-order resonance mode is used to characterize a second resonance in the working frequency band of the antenna.

[0022] The length of the outer arc of the fan-shaped patch structure is 1.5 times the wavelength corresponding to the center frequency of the antenna working frequency band; the ratio of the arc lengths of the outer and inner arcs of the fan-shaped patch structure is greater than 2.

[0023] The disturbance structure is symmetrical with respect to the angular bisector of the fan-shaped patch structure.

[0024] An air medium is filled between the fan-shaped patch structure and the ground structure.

[0025] The distance between the excitation signal and the center of the fan-shaped patch structure ranges from 1.07 times the inner diameter of the fan-shaped patch structure to 0.99 times the outer diameter of the fan-shaped patch structure.

[0026] The resonance mode adopted by the antenna is the first high-order resonance mode and the second higher-order resonant mode (α is the central angle of the fan-shaped patch structure).

[0027] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0028] (1) The antenna has circularly polarized beam scanning capability in the azimuth and elevation planes, that is, it can achieve a beam scanning range of -90° to 160° in the azimuth plane and a beam scanning range of 5° to 50° in the elevation plane.

[0029] (2) The antenna adopts a simple patch structure, and reasonably and flexibly adjusts two high-order modes on a single patch structure to achieve the continuous frequency scanning capability of the circularly polarized beam, effectively reducing the structural complexity of the traditional antenna array to achieve continuous two-dimensional beam frequency scanning performance. At the same time, it has the advantages of low profile, high gain, easy processing, and convenient mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a schematic diagram of the implementation process of a continuous two-dimensional beam frequency scanning circularly polarized antenna design method.

[0031] Figure 2 It is a top view structural schematic diagram and a reference coordinate system of Embodiment 1 of the continuous two-dimensional beam frequency scanning circularly polarized antenna of the present invention;

[0028] Figure 3 3D schematic diagram and reference coordinate system of embodiment 1 of the continuous two-dimensional beam frequency scanning circularly polarized antenna of the present invention; Figures 2 to 3 In the figure, 1 is the fan-shaped patch structure, 2 is the grounding structure, 3 is the short-circuit structure, 4 is the excitation signal, and 5 is the disturbance structure.

[0029] Figure 4 is the reflection coefficient (S) of the embodiment 1 of the continuous two-dimensional beam frequency scanning circularly polarized antenna of the present invention. 11 );

[0030] Figure 5 : is the axial ratio frequency response diagram of the embodiment 1 of the continuous two-dimensional beam frequency scanning circular polarization antenna of the present invention at different azimuth angles and elevation angles; (a) θ = 5°, (b) θ = 50°; is the azimuth angle, and θ is the elevation angle. ;

[0031] Figure 6 It is the radiation pattern of embodiment 1 of the continuous two-dimensional beam frequency scanning circularly polarized antenna of the present invention at different azimuth angles and frequencies. DETAILED DESCRIPTION

[0032] 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.

[0033] 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.

[0034] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0035] Figure 1 FIG. 1 is a flow chart of the antenna design method of the present invention. Figure 1 As shown, the method includes:

[0036] A first high-order resonant mode is determined, where the first high-order resonant mode is used to characterize a first resonance in the antenna's operating frequency band. When designing an antenna, different antenna design requirements may require different resonances, and therefore the first high-order resonant mode implemented on the antenna may be determined based on the antenna design requirements.

[0037] Determine whether there is a first high-order resonant mode on the fan-ring patch structure, where the fan-ring patch structure is an antenna radiation unit structure; if there is a first high-order resonant mode on the fan-ring patch structure, adjust the outer arc length and the ratio of the inner and outer arc lengths of the fan-ring patch structure to form a first odd-order resonant mode on the fan-ring patch structure; when designing the antenna, after determining the first high-order resonant mode, the central angle of the fan-ring patch structure can be determined according to the order of the resonant mode; and determine the inner and outer diameters of the fan-ring patch structure according to the operating frequency band of the antenna.

[0038] Determine a second high-order resonant mode, wherein the first high-order resonant mode is used to characterize the second resonance of the antenna working frequency band; when designing a beam scanning circularly polarized antenna, in addition to determining the first high-order resonant mode, it is also necessary to determine the second high-order resonant mode, wherein the second high-order resonant mode can also be determined according to the antenna design requirements, and the patch surface current distribution of the fan-ring patch structure in the second high-order resonant mode is determined, and the patch surface current distribution is used to determine the disturbance position of the disturbance structure of the second high-order resonant mode. By determining the first high-order resonant mode and the second high-order resonant mode, the design of the beam scanning circularly polarized antenna can be completed on the fan-ring patch structure.

[0039] Determine the patch surface current distribution of the fan-ring 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 and the inner arc end of the fan-ring patch structure to the grounding structure.

[0040] like Figure 2 and Figure 3 As shown, the present invention provides a continuous two-dimensional beam frequency scanning circularly polarized antenna and a design method thereof, comprising a fan-ring patch structure 1, a grounding structure 2, a short-circuit structure 3, an excitation signal 4 and a disturbance structure 5; the fan-ring patch structure constituting the antenna is a semi-closed structure, consisting of a fan-ring patch structure 1, a grounding structure 2 and a short-circuit structure 3.

[0041] The fan-shaped ring patch structure 1 is located above the ground structure 2 and is parallel to the ground structure 2. The fan-shaped ring patch structure 1 is connected to the ground structure 2 through a short-circuit structure 3 with two ring widths and one inner arc length; the excitation signal 4 is located on the angular bisector of the fan-shaped ring patch structure.

[0042] The length of the outer arc of the fan-shaped patch structure 1 is 1.5 times the wavelength corresponding to the center frequency of the antenna's operating frequency band; the ratio of the arc lengths of the outer and inner arcs of the fan-shaped patch structure 1 is greater than 2; the disturbance structure 5 is symmetrical with respect to the angular bisector of the fan-shaped patch structure; 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 1.07 times the inner diameter of the fan-shaped patch structure 1 to 0.99 times the outer diameter of the fan-shaped patch structure 1. The resonant mode used by the antenna is the first high-order resonant mode and the second higher-order resonant mode (α is the center angle of the fan-shaped ring patch structure), and its resonant mode is controlled by the center angle of the fan-shaped ring patch structure.

[0043] Compared with conventional circularly polarized antennas, the design method of a continuous two-dimensional beam frequency scanning circularly polarized antenna of the present invention adopts a novel fan-shaped ring patch structure, and realizes circular polarization by making the amplitude of the electric field components radiated by the first high-order resonant mode and the second high-order resonant mode of the antenna equal and the phase orthogonal relationship in the azimuth plane and the elevation plane. The structure of the antenna is simple and easy to design. The resonant frequency and the tilt angle of the circularly polarized beam are adjusted by correcting the arc length of the outer arc of the fan-shaped ring patch structure and the ratio of the arc length of the inner and outer arcs 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 an air medium (dielectric constant is 1), the distance between the fan-ring patch structure 1 and the ground structure 2 is 5mm, the outer diameter of the fan-ring patch structure is 39mm, the inner diameter is 13mm, the ratio of the inner and outer diameters is 3, and the center angle of the fan-ring patch structure is 270°; the radius of the ground structure is 90mm, the distance between the excitation signal and the center of the circle is 34mm, and the size radius of the excitation signal is 0.65mm; the length and width of the disturbance structure are 15mm and 3.5mm respectively, and the angle between the central axis of the disturbance structure and the angular bisector of the fan-ring patch structure is 60°.

[0046] Compare with Figure 4 , Figure 4 The reflection coefficient S of a continuous two-dimensional beam frequency scanning circularly polarized antenna is given by 11 .Depend on Figure 4 It can be seen that the working frequency range of the antenna (S 11 >-10dB) is 2.32~2.84GHz, and the relative bandwidth reaches 20.2%. At the same time, it can be seen from the figure that the antenna has a dual-harmonic broadband radiation characteristic.

[0047] Compare with Figure 5 (a) Figure 5(a) shows the axial ratio frequency response of the antenna at different azimuth angles when the elevation angle is 5°. Figure 5 (a) It can be seen that the antenna exhibits good continuous circular polarization beam frequency scanning capability when the pitch angle is 5°. When the operating frequency moves from the low frequency to the high frequency within the band, the azimuth angle changes continuously from -90° to 160° as the frequency increases. It can be seen that when the pitch angle is 5°, a 250° beam frequency scanning range can be achieved in the azimuth plane.

[0048] Compare with Figure 5 (b) Figure 5 (b) Give the axial ratio frequency response diagram of the antenna at different azimuth angles when the elevation angle is 50°. Figure 5 (b) It can be seen that the antenna exhibits good continuous circular polarization beam frequency scanning capability when the pitch angle is 50°. When the operating frequency moves from low frequency to high frequency within the band, the azimuth angle changes from -30° to 130° as the frequency increases. It can be seen that when the pitch angle is 50°, a 160° beam frequency scanning range can be achieved in the azimuth plane, and when the azimuth angle is 120°, the antenna has a wide axial ratio bandwidth (15.2%). Figure 5 From the analysis of the axial ratio frequency response diagram, it can be obtained that the antenna can realize continuous two-dimensional circular polarization beam frequency scanning in the angle range of: azimuth angle -90°~160°(250°) and elevation angle 5°~50°(45°).

[0049] Compare with Figure 6 , Figure 6 The radiation patterns of the antenna at different azimuth angles and frequencies are given. Figure 6 It can be seen that when the frequency f is 2.45GHz, the azimuth plane is located at Planar and circular polarization beams are best pointed at When the frequency f is 2.53 GHz, the azimuth plane is located Planar and circular polarization beams are best pointed at When the frequency f is 2.57 GHz, the azimuth plane is located Planar and circular polarization beams are best pointed at When the frequency f is 2.6 GHz, the azimuth plane is located Planar and circular polarization beams are best pointed at When the frequency f is 2.65GHz, the azimuth plane is located Planar and circular polarization beams are best pointed at When the frequency f is 2.68 GHz, the azimuth plane is located Planar and circular polarization beams are best pointed at 10°); when the frequency f is 2.7GHz, the azimuth plane is located Planar and circular polarization beams are best pointed at 10°); when the frequency f is 2.7GHz, the azimuth plane is located Planar and circular polarization beams are best pointed at 10°); when the frequency f is 2.69GHz, the azimuth plane is located at Planar and circular polarization beams are best pointed at When the frequency f is 2.69 GHz, the azimuth plane is located Planar and circular polarization beams are best pointed at Depend on Figure 6 It can be seen that the antenna can achieve continuous two-dimensional circular polarization beam scanning that varies with frequency.

[0050] To summarize, the continuous two-dimensional beam frequency scanning circularly polarized antenna designed by the present invention can obtain good two-dimensional circularly polarized beam scanning capability for different operating frequency bands of wireless communication systems by simply adjusting the central angle, inner and outer diameters and their ratio of the fan-ring 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 method for designing a continuous two-dimensional beam frequency scanning circularly polarized antenna, characterized in that: include: Determining a first high-order resonance mode, where the first high-order resonance mode is used to characterize a first resonance in an operating frequency band of the antenna; Determine whether there is a first high-order resonant mode on the fan-shaped ring patch structure, where the fan-shaped ring patch structure is an antenna radiation unit structure; If a first high-order resonant mode exists on the fan-shaped patch structure, the outer arc length and the ratio of the inner and outer arc lengths of the fan-shaped patch structure are adjusted to form the first high-order resonant mode on the fan-shaped patch structure.

2. The method according to claim 1, characterized in that The method comprises: Determining a second higher-order resonance mode, where the second higher-order resonance mode is used to characterize a second resonance in an operating frequency band of the antenna; Determine whether there is a second high-order resonant mode on the fan-ring patch structure. If there is a second high-order resonant mode on the fan-ring patch structure, adjust the outer arc length and the ratio of the inner and outer arc lengths of the fan-ring patch structure to form a second high-order resonant mode on the fan-ring patch structure.

3. The method according to claims 1 and 2, characterized in that The method comprises: Determine the patch surface current distribution of the fan-shaped patch structure in the second high-order resonance mode, wherein the patch surface current distribution is used to determine the disturbance position of the disturbance structure in the second high-order resonance mode; Determine the patch surface current distribution of the fan-shaped ring patch structure in the first odd-order resonance mode, wherein the patch surface current distribution is used to determine the excitation position of the excitation signal of the fan-shaped ring patch structure; 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 and the inner arc end of the fan-shaped patch structure with the grounding structure.

4. A continuous two-dimensional beam frequency scanning circularly polarized 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 and the disturbance structure are used to form a first high-order resonance mode and a second high-order resonance mode; The excitation signal is located on the angular bisector of the fan-shaped patch structure, and is connected to the fan-shaped patch structure and the ground structure.

5. A continuous two-dimensional beam frequency scanning circularly polarized antenna as described in claim 4, characterized in that: the first high-order resonant mode is used to characterize the first resonance of the antenna working frequency band, and the second high-order resonant mode is used to characterize the second resonance of the antenna working frequency band.

6. A continuous two-dimensional beam frequency scanning circularly polarized antenna as described in claim 4, characterized in that: the length of the outer arc of the fan-ring patch structure is 1.5 times the wavelength corresponding to the center frequency of the antenna's working frequency band; the ratio of the arc lengths of the outer and inner arcs of the fan-ring patch structure is greater than 2.

7. A continuous two-dimensional beam frequency scanning circular polarization antenna as described in claim 4, characterized in that: the disturbance structure is symmetrical with respect to the angular bisector of the fan-shaped patch structure.

8. A continuous two-dimensional beam frequency scanning circular polarization antenna as claimed in claim 4, characterized in that: an air medium is filled between the fan-shaped patch structure and the ground structure.

9. A continuous two-dimensional beam frequency scanning circularly polarized antenna as described in claim 4, characterized in that the distance between the excitation signal and the center of the fan-shaped patch structure ranges from 1.07 times the inner diameter of the fan-shaped patch structure to 0.99 times the outer diameter of the fan-shaped patch structure.

10. The method according to claim 1 and 2, characterized in that: the resonance mode adopted by the antenna is the first high-order resonance mode and the second higher-order resonant mode (α is the central angle of the fan-shaped patch structure).

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