A broadband circularly polarized millimeter wave antenna

Abstract

This invention discloses a broadband circularly polarized millimeter-wave antenna. It uses a magnetoelectric dipole antenna as a linearly polarized antenna source, satisfying the characteristics of wide impedance bandwidth and stable gain. A polarizer is then used to increase the gain while simultaneously achieving circular polarization. This design eliminates the need for a complex feed network, reducing design complexity, improving efficiency, and providing a wide axial ratio bandwidth. The invention includes a polarizer 1 and a magnetoelectric dipole antenna 2. The polarizer 1 consists of multiple polarization layers, each composed of spaced-apart grating media 11 and air plates 12. Adjacent polarization layers satisfy the following conditions: the grating media 11 and air plates 12 are cuboid structures; the length of the grating media 11 is less than the length of the air plate 12; the upper right corner of the lower grating media 11 is connected to the upper left corner of the upper grating media 11; along the height direction of the grating media 11, the magnetoelectric dipole antenna 2 is separated from the polarizer 1 by a distance g, and is supplied to the antenna sequentially through a rectangular waveguide-to-SIW structure 3 and a flange.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antennas, in particular to a wideband circularly polarized millimeter wave antenna. BACKGROUND

[0002] The wideband circularly polarized millimeter wave antenna is a wireless communication component for transmitting and receiving millimeter waves. With the development and popularization of 5G technology, the wideband circularly polarized millimeter wave antenna technology, as one of the core technologies, is increasingly valued.

[0003] How to improve the antenna gain and realize circular polarization is an important development direction of the wideband circularly polarized millimeter wave antenna, especially in the case of ensuring small cost and size. The existing wideband circularly polarized millimeter wave antenna mainly realizes the antenna gain or circular polarization in the following ways:

[0004] 1. Use antenna array to improve antenna gain: Array antenna is composed of some basic antennas with the same structure and size arranged according to certain rules according to the principle of electromagnetic wave interference in space. Array antenna can easily realize very narrow beam. For a unit antenna with a certain beam width, there is an array spacing that can make it obtain the maximum array gain. According to the theory of antenna array, the structure, number, arrangement of array elements and the current amplitude and phase distribution of the whole array can be adjusted to effectively improve the antenna gain. However, this method has the defects of using complex feed network, increasing the design difficulty, high loss and low efficiency of the antenna, which is not suitable for millimeter wave communication;

[0005] 2. Use lens antenna to improve the gain of the antenna: Lens antenna is designed to collimate the incident energy that diverges in the desired direction in nature. Point source acts as a feed that emits microwave energy to the optical lens surface. The optical surface of the lens forces the radiated spherical wave front to become a collimated wave front. This can prevent unwanted energy from spreading, thereby improving the gain of the antenna. In general practice, collimating lenses are made of dielectric materials with limited dielectric constant values, but these can also be constructed using materials that exhibit less than unit refractive index at radio frequencies. Lens antenna follows the reciprocity theorem, so it can be used at both the transmitting end and the receiving end. However, the volume of the lens antenna is generally large, the production efficiency is low, the manufacturing difficulty is relatively large, and the manufacturing cost is often high, which cannot meet the needs of large-scale production;

[0006] 3. Use orthogonal excitation of radiating elements to realize circular polarization: that is, a linearly polarized signal is distributed into two signals with equal amplitude and 90-degree phase difference through a 90-degree bridge, which excites the two orthogonal polarized input ends of a dual linearly polarized antenna, thereby forming circularly polarized radiation. This way of realizing circular polarization has good effect, but it needs special feed network and is complex to implement, with small bandwidth, which is not suitable for wideband circularly polarized millimeter wave antennas.

[0007] Therefore, for the above situation, how to improve the existing wideband circularly polarized millimeter wave antenna, so as to improve the gain of the wideband circularly polarized millimeter wave antenna and realize circular polarization, has become an important technical problem to be solved by the person skilled in the art. SUMMARY

[0008] The application discloses a wideband circularly polarized millimeter wave antenna, which uses a magnetoelectric dipole antenna as a linearly polarized antenna source and uses a polarizer to increase gain and realize circular polarization.

[0009] The wideband circularly polarized millimeter wave antenna provided by the application comprises a polarizer 1 and a magnetoelectric dipole antenna 2.

[0010] The polarizer 1 is composed of multiple polarizing layers, wherein each layer is composed of a grating medium 11 and an air plate 12 arranged at intervals.

[0011] The two adjacent polarizing layers satisfy that the grating medium 11 and the air plate 12 are cuboid structures, the length of the grating medium 11 is less than the length of the air plate 12, and the upper right corner of the grating medium 11 in the lower layer is connected to the upper left corner of the grating medium 11 in the upper layer.

[0012] Along the height direction of the grating medium 11, the magnetoelectric dipole antenna 2 is spaced apart from the polarizer 1 by a distance g, and sequentially passes through a rectangular waveguide to SIW structure 3 and a flange supply antenna.

[0013] Preferably,

[0014] The magnetoelectric dipole antenna 2 is composed of multiple dielectric substrates.

[0015] Preferably,

[0016] The dielectric substrate is made of Rogers 5880 laminated PCB material.

[0017] Preferably,

[0018] The magnetoelectric dipole antenna 2 is composed of three dielectric substrates.

[0019] Preferably,

[0020] The polarizer 1 is printed by FR4-epoxy resin.

[0021] Preferably,

[0022] The polarizer 1 is composed of 13-17 polarizing layers.

[0023] Preferably,

[0024] Further comprising a support structure 4.

[0025] The polarizer 1 is mounted on the outside of the support structure 4, and the magneto-electric dipole antenna 2 and the rectangular waveguide to SIW structure 3 are arranged inside the support structure 4.

[0026] The wideband circularly polarized millimeter wave antenna provided by the application comprises a polarizer 1 and a magneto-electric dipole antenna 2; the polarizer 1 is composed of multiple polarizing layers, each of which is composed of a grating medium 11 and an air plate 12 arranged at intervals; the grating medium 11 and the air plate 12 of adjacent two layers are cuboid structures, the length of the grating medium 11 is less than that of the air plate 12, and the upper right corner of the grating medium 11 in the lower layer is connected to the upper left corner of the grating medium 11 in the upper layer; along the height direction of the grating medium 11, the magneto-electric dipole antenna 2 is apart from the polarizer 1 by g, and sequentially passes through a rectangular waveguide to SIW structure 3 and a flange-fed antenna. By taking the magneto-electric dipole antenna as a linearly polarized antenna source, the wideband circularly polarized millimeter wave antenna of the application increases the gain by using the polarizer, realizes circular polarization at the same time, does not need a complex feed network, reduces the design difficulty, improves the efficiency, and has a wide axial ratio bandwidth. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative effort based on these drawings.

[0028] Figure 1 It is a perspective view of the wideband circularly polarized millimeter wave antenna embodiment of the application;

[0029] Figure 2 It is a top view of the wideband circularly polarized millimeter wave antenna embodiment of the application;

[0030] Figure 3 It is a front view of the polarizer 1 in the wideband circularly polarized millimeter wave antenna embodiment of the application;

[0031] Figure 4 It is a phase difference diagram in the orthogonal direction obtained by using periodic boundary simulation of CST software in the wideband circularly polarized millimeter wave antenna embodiment of the application;

[0032] Figure 5 It is an amplitude difference diagram in the orthogonal direction obtained by using periodic boundary simulation of CST software in the wideband circularly polarized millimeter wave antenna embodiment of the application;

[0033] Figure 6The figure of gain-frequency curve without polarizer 1 in the embodiment of the wideband circularly polarized millimeter wave antenna of the application;

[0034] Figure 7 The figure of the influence of the height h of polarizer 1 on the axial ratio bandwidth in the embodiment of the wideband circularly polarized millimeter wave antenna of the application; Figure 8 The structure diagram of the magnetoelectric dipole antenna 2 in the embodiment of the wideband circularly polarized millimeter wave antenna of the application;

[0035] Figure 9 The top view structure diagram of the polarizer 1 and the magnetoelectric dipole antenna 2 in the embodiment of the wideband circularly polarized millimeter wave antenna of the application;

[0036] Figure 10 The path diagram of the electromagnetic wave through the polarizer 1 in the embodiment of the wideband circularly polarized millimeter wave antenna of the application. DETAILED DESCRIPTION

[0037] The application discloses a wideband circularly polarized millimeter wave antenna, which uses a magnetoelectric dipole antenna as a linearly polarized antenna source, uses a polarizer to increase gain, and realizes circular polarization.

[0038] The technical solutions in the embodiments of the application will be clearly and completely described in connection with the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application. Please refer to Figures 1 to 6 The wideband circularly polarized millimeter wave antenna provided by the embodiments of the application comprises a polarizer 1 and a magnetoelectric dipole antenna 2.

[0039] The polarizer 1 is composed of multiple polarizing layers, wherein each layer is composed of a grating medium 11 and an air plate 12 arranged at intervals.

[0040] The grating medium 11 and the air plate 12 are cuboid structures, the length of the grating medium 11 is less than the length of the air plate 12, and the upper right corner of the grating medium 11 in the lower layer is connected to the upper left corner of the grating medium 11 in the upper layer.

[0041] The magnetoelectric dipole antenna 2 is g away from the polarizer 1 along the height direction of the grating medium 11, and sequentially passes through a rectangular waveguide to SIW structure 3 and a flange supply antenna.

[0042] In the application, the overall structure of the antenna is composed of the polarizer 1 and the magnetoelectric dipole antenna 2, wherein the polarizer 1 is composed of multiple polarizing layers. Figure 1As shown, the polarizer 1 composed of the multilayer polarization layer is in operation, and does not need a complex feed structure, and can realize a wide axial ratio bandwidth and high gain by feeding through the magnetic electric dipole antenna to provide linearly polarized electromagnetic waves, and has the characteristics of wide bandwidth and low cross-polarization rate. According to the current test, the axial ratio bandwidth reaches 30%, and the maximum gain can reach 15dBic.

[0043] Specifically, the polarizer 1 can be manufactured by using a printed circuit board technology, for example, can be printed by selecting FR4-epoxy resin, and the dielectric constant of the FR4-epoxy resin is 4.4 and the loss tangent is 0.02. The polarizer 1 is composed of a plurality of grating media 11 with a thickness of W1 and an air plate 12 with a thickness of W2, wherein the length of the grating medium 11 is a and the width is b, the distance between the two adjacent grating media 11 in the same layer is s, and s>a is satisfied. In addition, the polarizer 1 is designed as a cuboid structure, mainly to improve the gain, and the height of the cuboid is h, and the distance between the magnetic electric dipole antenna 2 and the polarizer 1 is g.

[0044] It should be pointed out that, compared with other medium polarizers in the field, the structure does not need 3D printing technology, but uses PCB technology which is more suitable for millimeter wave circuit, and can be better integrated with millimeter wave circuit. The design is suitable for a variety of end-fire linearly polarized antenna sources, and is circularly polarized.

[0045] The effect of the wideband circularly polarized millimeter wave antenna of the present application will be analyzed as follows: Figure 3 and Figure 10 , how the linearly polarized electromagnetic wave is converted to circularly polarized by the present application can be seen from Figure 3 It can be seen that the polarizer 1 is composed of grating media 11 and air plate 12, and when the vertically polarized electromagnetic wave passes through the polarizer 1, the electric field in the vertical direction can be decomposed into two orthogonal electric fields E1 and E2. Because the materials in the two directions are different, the equivalent dielectric constants in the two directions are different, so the electromagnetic waves e1 and e2 move at different speeds in the respective regions, thereby causing a phase difference between the orthogonal directions. Specifically, the dielectric constants in the orthogonal directions can be guided by formula one, Formula two ε y =1+(ε r -)r, wherein ε r is the dielectric constant of the polarizer 4.4, that is, FR4, and r is the proportion of the polarizer 1 and air. Finally, the phase difference can be When the phase difference meets 90°, the circular polarization can be realized, h is the length of the polarizer, and the phase difference can be effectively changed by controlling the value of h. Since the electric field amplitudes in the orthogonal directions are almost the same, the circularly polarized radiation can be realized by controlling h to make the phase difference meet 90°. Since the medium polarizer is not sensitive to frequency, the phase requirement can be met in a wide frequency band range, so that a wide axial ratio bandwidth is obtained, which is required for millimeter wave communication.

[0046] By using the CST software to simulate the unit with periodic boundary, the phase difference and amplitude difference in the orthogonal directions can be obtained, as shown in FIGS. 1 and 2. Figure Two 、 Three The simulation results show that in the frequency range of 55-75 GHz, the phase difference is about -90° or 270°, and the amplitude difference is close to 0, which meets the condition of realizing wideband circular polarization.

[0047] For how the application realizes gain enhancement, the polarizer 1 can be equivalent to a uniform medium, and the paths of the electromagnetic wave through the uniform medium of the polarizer 1 can be divided into three types: Path1, Path2 and Path3. According to Snell's law, we can obtain Φ1< Φ3 and Φ2< Φ4, so only Path1 can effectively improve the gain. By adjusting the height h or width b of the polarizer 1, more electromagnetic waves pass through the polarizer 1 in this path, so that the effect of gain enhancement can be achieved. In addition, when the height h or width b of the polarizer 1 is increased, on the one hand, more electromagnetic waves pass through Path1, and on the other hand, the volume and loss of the polarizer 1 are also increased, so that a compromise parameter needs to be selected in actual use.

[0048] Preferably,

[0049] The magneto-electric dipole antenna 2 is composed of multiple dielectric substrates.

[0050] Preferably,

[0051] The dielectric substrate is made of Rogers 5880 laminated PCB material.

[0052] Preferably,

[0053] The magneto-electric dipole antenna 2 is composed of three dielectric substrates.

[0054] It should be noted that the magneto-electric dipole antenna 2 can be composed of three layers of structure, and the three layers of materials can be made of Rogers 5880 laminated PCB material. This structure design and material selection are on the one hand for performance consideration, and on the other hand to meet the demand of large-scale production.

[0055] Preferably,

[0056] The polarizer 1 is printed by FR4-epoxy resin.

[0057] Preferably,

[0058] The polarizer 1 is composed of 13-17 polarizing layers.

[0059] It should be noted that the polarizer 1 can be printed by FR4-epoxy resin, wherein the polarizer 1 can be composed of 13-17 polarizing layers, and the optimal number of layers is 15.

[0060] Preferably,

[0061] The support structure 4 is further included;

[0062] The polarizer 1 is mounted on the outside of the support structure 4, and the magneto-electric dipole antenna 2 and the rectangular waveguide to SIW structure 3 are arranged inside the support structure 4.

[0063] The wideband circularly polarized millimeter wave antenna provided by the application comprises a polarizer 1 and a magneto-electric dipole antenna 2; the polarizer 1 is composed of multiple polarizing layers, wherein each layer is composed of a grating medium 11 and an air plate 12 arranged at intervals; the adjacent two polarizing layers satisfy that the grating medium 11 and the air plate 12 are cuboid structures, the length of the grating medium 11 is less than the length of the air plate 12, the upper right corner of the grating medium 11 in the lower layer is connected with the upper left corner of the grating medium 11 in the upper layer; along the height direction of the grating medium 11, the magneto-electric dipole antenna 2 is away from the polarizer 1 by g, and sequentially passes through a rectangular waveguide to SIW structure 3 and a flange feed antenna. By taking the magneto-electric dipole antenna as a linearly polarized antenna source, the wideband circularly polarized millimeter wave antenna of the application increases the gain by using the polarizer, realizes circular polarization at the same time, does not need a complex feed network, reduces the design difficulty, improves the efficiency, and has a relatively wide axial ratio bandwidth.

[0064] The wideband circularly polarized millimeter wave antenna provided by the application is described in detail above, for the general technical personnel in the art, according to the idea of the embodiment of the application, the specific implementation mode and the application range will have the change, according to the above, the content of the specification should not be understood as the limitation of the application.

Claims

1. A broadband circularly polarized millimeter wave antenna, characterized in that, The polarizer (1) and the magnetoelectric dipole antenna (2) are included. The polarizer (1) is composed of multiple polarizing layers, each of which is composed of a grating medium (11) and an air plate (12) arranged at intervals. The two adjacent polarizing layers satisfy that the grating medium (11) and the air plate (12) are cuboid structures, the length of the grating medium (11) is less than that of the air plate (12), and the upper right corner of the grating medium (11) in the lower layer is connected with the upper left corner of the grating medium (11) in the upper layer. The magnetoelectric dipole antenna (2) is g away from the polarizer (1) along the height direction of the grating medium (11), and sequentially passes through the rectangular waveguide to SIW structure (3) and the flange supply antenna.

2. The wideband circularly polarized millimeter wave antenna of claim 1, wherein, The magnetoelectric dipole antenna (2) is composed of multiple dielectric substrates. The dielectric substrate is made of Rogers 5880 laminated PCB material. The polarizer (1) is printed by FR4-epoxy resin.

3. The wideband circularly polarized millimeter wave antenna of claim 2, wherein, The magnetoelectric dipole antenna (2) is composed of three dielectric substrates.

4. The wideband circularly polarized millimeter wave antenna of claim 2, wherein, The polarizer (1) is composed of 13-17 polarizing layers.

5. The wideband circularly polarized millimeter wave antenna of claim 2, wherein, A support structure (4) is further included. The polarizer (1) is installed on the outside of the support structure (4), and the magnetoelectric dipole antenna (2) and the rectangular waveguide to SIW structure (3) are arranged inside the support structure (4).

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