High-isolation miniaturized OAM antenna array based on defect slotting

Abstract

The invention discloses a high-isolation miniaturized OAM antenna array based on defect slotting. The high-isolation miniaturized OAM antenna array comprises a dielectric substrate arranged on the top layer and a grounding plate arranged below the dielectric substrate. A circular antenna array formed by four same circular antenna units is arranged on the dielectric substrate; the circular antenna unit comprises a circular patch and n triangular patches which are uniformly arranged along the outer ring of the circular patch; and the T-shaped power dividers are connected with the two adjacent triangular patches for feeding, and according to the OAM antenna array provided by the invention, the reconfiguration of an OAM mode can be realized. The antenna has the advantages of miniaturized structure, low profile, high isolation and easiness in manufacturing. The OAM mode of the vortex electromagnetic wave can be changed only by changing the feed phase under the condition that the antenna unit, the array combination mode and the defected ground structure are not changed.

Description

Technical Field

[0001] The invention belongs to the field of fully automated products and relates to a high-isolation miniaturized OAM antenna array based on defect slotting. Background Art

[0002] Antennas are an essential component of wireless communication systems, and their importance is self-evident. The function of antennas is to radiate or receive electromagnetic wave signals in a direction. With the vigorous development of wireless communications, people have higher and higher requirements for spectrum utilization. Although expanding the working bandwidth of antennas can improve spectrum utilization to a certain extent, it cannot solve the problem of frequency as a limited resource from the source. The orbital angular momentum carried by vortex electromagnetic waves opens up new degrees of freedom for electromagnetic waves, thus providing a new direction for solving the problem of tight spectrum resources in wireless communication systems. Most of the research on vortex electromagnetic waves focuses on the OAM generation method and OAM electromagnetic characteristics, and there is little research on the reconfigurability of OAM modes. Summary of the invention

[0003] In order to solve the above problems, the technical solution adopted by the present invention is: a high-isolation miniaturized OAM antenna array based on defect slots, comprising

[0004] A dielectric substrate disposed on the top layer and a grounding plate disposed below the dielectric substrate;

[0005] A circular antenna array consisting of four identical circular antenna units is arranged on the dielectric substrate;

[0006] The circular antenna unit includes a circular patch and n triangular patches evenly arranged along the outer circle of the circular patch;

[0007] And a T-type power divider connected to two adjacent triangular patches for feeding.

[0008] Furthermore: the lines connecting the centers of the circular antenna units form a square.

[0009] Furthermore: the depth of the square groove between adjacent triangular patches is 1 / 8 wavelength.

[0010] Furthermore: the radius of the circular patch is 1 / 2 wavelength.

[0011] Furthermore: evenly arranged cross-shaped defect grounds are arranged on the ground plate to form a cross-shaped defect ground array;

[0012] The interval between adjacent cross-shaped defects is about 1 / 8 wavelength;

[0013] The cross-shaped defect ground array is located in the middle position below the circular antenna array.

[0014] Furthermore: the T-type power divider includes a feeding port, and a one-way branch and a two-way branch connected to the feeding port, the one-way branch is longer than the two-way branch by a quarter wavelength, and the feeding port is arranged at the edge of the dielectric substrate.

[0015] Furthermore: n≥2.

[0016] The invention provides a high-isolation miniaturized OAM antenna array based on defect slots, which can realize the reconfiguration of OAM modes. It has the advantages of structural miniaturization, low profile, high isolation and easy manufacturing. Without changing the antenna unit, array combination mode and defect ground structure, the OAM mode of the vortex electromagnetic wave can be changed by only changing the feeding phase.

[0017] The invention has a simple structure and low cost and has broad application prospects.

[0018] The present invention has higher array element isolation and better OAM purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 A schematic diagram of a high-isolation miniaturized OAM antenna array based on defect slots in an example of the present invention;

[0021] Figure 2 A top view of a high-isolation miniaturized OAM antenna array based on defect slots in an example of the present invention;

[0022] Figure 3 Schematic diagram of the distribution of clockwise feeding of the antenna unit in an example of the present invention, wherein (a) is the far-field amplitude case, and (b) is the phase case;

[0023] Figure 4 Schematic diagram of the distribution of counterclockwise feeding of the antenna unit in an example of the present invention, wherein (a) is the far-field amplitude case, and (b) is the phase case;

[0024] Figure 5 Schematic diagram of OAM mode purity when feeding the antenna unit clockwise in an example of the present invention;

[0025] Figure 6 It is a schematic diagram of the normalized directivity coefficient of the antenna unit fed in a clockwise direction in an example of the present invention.

[0026] Figure numerals: 1. first feeding port, 2. second feeding port, 3. third feeding port, 4. fourth feeding port, 5. one-way branch, 6. dielectric substrate, 7. cross-shaped defect ground, 8. square groove, 9. circular patch, 10. two-way branch, 11. ground plate. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Figure 1 A schematic diagram of a high-isolation miniaturized OAM antenna array based on defect slots in an example of the present invention;

[0030] Figure 2 A top view of a high-isolation miniaturized OAM antenna array based on defect slots in an example of the present invention;

[0031] A high-isolation miniaturized OAM antenna array based on defect slots, comprising

[0032] A dielectric substrate 6 disposed on the top layer and a grounding plate 11 disposed below the dielectric substrate 6;

[0033] The dielectric substrate 6 and the grounding plate 11 are in square shape;

[0034] A circular antenna array consisting of four identical circular antenna units is arranged on the dielectric substrate 6; the circular antenna unit includes a circular patch 9 and n triangular patches evenly arranged along the outer circle of the circular patch 9; in this embodiment, n is 9;

[0035] And a T-type power divider connected to two adjacent triangular patches for feeding.

[0036] The radius of the circular patch 9 is 1 / 2 wavelength. Too large an array radius will reduce the purity of the OAM mode, and too small an array radius will deteriorate the isolation between array elements.

[0037] The lines connecting the centers of the circular antenna units form a square.

[0038] The depth of the square slot 8 between adjacent triangular patches is 1 / 8 wavelength, and each antenna unit is evolved from a circular patch 9 with a slot 8, so that the operating frequency of the original antenna can be reduced to 2 / 5 at the same size.

[0039] The grounding plate 11 is provided with evenly arranged cross-shaped defective ground 7 grooves to form a cross-shaped defective ground 7 array;

[0040] The interval between adjacent cross-shaped defects 7 is about 1 / 8 wavelength;

[0041] The cross-shaped defect ground 7 array is located in the middle position below the circular antenna array. Under the premise of ensuring the purity of the OAM mode, the isolation between the array elements is improved. The spacing between the cross-shaped defect ground 7 is about 1 / 8 wavelength. Too large spacing will reduce the isolation, and too small spacing will reduce the antenna gain.

[0042] The T-type power divider includes a feeding port, and a first branch 5 and a second branch 10 connected to the feeding port.

[0043] The one-way branch 5 is one quarter wavelength longer than the two-way branch 10, so that the two outputs of the T-type power divider have a ninety-degree phase difference, and the feeding position differs by forty-five degrees relative to the center of the antenna unit to excite the high-order mode TM of the circular patch 9. 21 mode, so that a single antenna unit already carries the first-order OAM. In order to ensure the input matching of a single antenna unit, it is necessary to adjust the branch width of the T-type power divider. Under the premise of ensuring the processing accuracy, multi-section impedance matching is used to make the antenna have a larger working bandwidth. Finally, the OAM mode of the vortex electromagnetic wave can be flexibly controlled through the feeding ports of the four antenna units. The feeding port is set at the edge of the dielectric substrate 6.

[0044] There are cross-shaped defect grounds 7 with certain intervals between adjacent circular antenna units on the ground plane 11, thereby ensuring that the isolation between adjacent circular antenna units is less than -25dB. By performing equal-amplitude feeding in a certain direction at the first feeding port 1, the second feeding port 2, the third feeding port 3, and the fourth feeding port 4 of the four circular antenna units and maintaining a 90-degree phase difference between adjacent ports, the OAM mode can be superimposed.

[0045] Figure 3Schematic diagram of the distribution of clockwise feeding of antenna units in an example of the present invention, where (a) is the far-field amplitude case, and (b) is the phase case. The four circular antenna units are fed with equal amplitude clockwise, and a phase difference of ninety degrees is made between adjacent feeding ports, so that the second-order OAM can be obtained; on the contrary, if the feeding is performed counterclockwise, the zero-order OAM is obtained, such as Figure 4 As shown, Figure 4 Schematic diagram of the distribution of counterclockwise feeding of the antenna unit in an example of the present invention, wherein (a) is the far-field amplitude case, and (b) is the phase case;

[0046] In order to observe the OAM mode distribution more intuitively, the OAM purity was calculated, and the results are as follows: Figure 5 As shown in the figure, the purity of the second-order OAM mode reaches 86.9%, which shows that the superimposed OAM mode still has a very high purity.

[0047] Finally, the normalized directivity coefficient of the second-order OAM is given, such as Figure 6 As shown, when the pitch angle is zero degrees, the directivity diagram has an obvious depression, which is caused by the phase singularity of OAM.

[0048] While keeping all parameters unchanged, we analyze the two feeding phases to observe the changes in the OAM mode. Since the antenna unit of the inventive structure carries a first-order OAM, the feeding phases of the four antenna units are clockwise and counterclockwise, respectively, and the phase difference between adjacent antenna units is ninety degrees.

[0049] The high-isolation miniaturized OAM antenna array based on defect slots, without changing parameters such as antenna units, array combination mode, defect ground structure, etc., only needs to perform equal-amplitude feeding along different directions while maintaining a ninety-degree phase difference between adjacent units, so as to obtain vortex electromagnetic waves of different modes.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-isolation miniaturized OAM antenna array based on defect slotting, characterized in that: include A dielectric substrate disposed on the top layer and a grounding plate disposed below the dielectric substrate; A circular antenna array consisting of four identical circular antenna units is arranged on the dielectric substrate; The circular antenna unit includes a circular patch and n triangular patches evenly arranged along the outer circle of the circular patch; And a T-type power divider connected to two adjacent triangular patches for feeding.

2. The high-isolation miniaturized OAM antenna array based on defect slotting according to claim 1, characterized in that: The lines connecting the centers of the circular antenna units form a square.

3. The high isolation miniaturized OAM antenna array based on defect slotting according to claim 1, characterized in that: The depth of the square grooves between adjacent triangular patches is 1 / 8 wavelength.

4. The high isolation miniaturized OAM antenna array based on defect slotting according to claim 1, characterized in that: The radius of the circular patch is 1 / 2 wavelength.

5. The high isolation miniaturized OAM antenna array based on defect slotting according to claim 1, characterized in that: The grounding plate is provided with evenly arranged cross-shaped defect grounds to form a cross-shaped defect ground array; The interval between adjacent cross-shaped defects is about 1 / 8 wavelength; The cross-shaped defect ground array is located in the middle position below the circular antenna array.

6. The high isolation miniaturized OAM antenna array based on defect slotting according to claim 1, characterized in that: The T-type power divider comprises a feeding port, and a one-way branch and a two-way branch connected to the feeding port, wherein the one-way branch is longer than the two-way branch by a quarter wavelength, and the feeding port is arranged at an edge position of the dielectric substrate.

7. The high isolation miniaturized OAM antenna array based on defect slotting according to claim 1, characterized in that: n≥2。

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