Adjustable phase line-to-circular polarization converter based on improved leaf-shaped metasurface

Abstract

The utility model discloses an adjustable phase line-to-circular polarization converter based on an improved leaf-shaped metasurface, which belongs to the technical field of wireless communication and comprises a metal layer and a dielectric layer. Through the above mode, the polarization converter can realize a polarization conversion function through the double-layer metasurface, has better matching characteristics and circular polarization characteristics, realizes line-to-circular polarization, is convenient in phase modulation, can realize wider bandwidth, uses a linear polarization feed source, is low in cost, is simple in structure, and is easy to popularize. The antenna has a polarization selection function, only X-polarized electromagnetic waves are used, electromagnetic waves in other directions are filtered out, the strip line is used as the true delay line to carry out phase adjustment and polarization torsion, the electromagnetic waves in the X-polarized direction can be twisted into Y-polarized electromagnetic waves, meanwhile, the phase can be adjusted by changing the length of the true delay line, the design is simple, modification is convenient, and the antenna is convenient to use. And linear phase can be realized in a relatively wide frequency band.

Description

Technical Field

[0001] The utility model relates to the technical field of wireless communications, and in particular to an adjustable phase line to circular polarization converter based on an improved leaf-shaped metasurface. Background Art

[0002] With the rapid development of wireless communication technology, today's society has basically entered the 5G era. However, it also has shortcomings, such as: relying on base stations, it is difficult to achieve ocean and high-altitude communications, and frequency band resources are in short supply. In recent years, in order to solve these problems, technologies such as satellite communications have rapidly emerged, and the demand for broadband high-gain antennas has increased. Traditional high-gain antennas have high profiles and high costs, making them difficult to be commercialized on a large scale. In order to overcome this limitation, planar array antennas based on printed circuit board technology provide a good solution. Among them, planar air-fed array antennas can be used for phase compensation by changing the unit size, etc., without the need for complex feeder circuit design, which greatly reduces the cost, so they have been widely used. On the other hand, in order to reduce polarization loss and achieve high-quality wireless communication, the antenna is often required to have circular polarization characteristics. Generally speaking, circular polarization requires a circular polarization feed source, which has a complex structure and high cost. Therefore, using a linear polarization feed source and realizing circular polarization characteristics through a metasurface has become a research direction today.

[0003] For example, Chinese patent CN218648144U discloses a single-layer omnidirectional circularly polarized transmission array antenna based on a polarization conversion metasurface, wherein the antenna includes a cylindrical polarization conversion array and a biconical antenna, wherein the cylindrical polarization conversion array includes a cylindrical dielectric cylinder, on which a plurality of periodically arranged transmission polarization conversion metasurface units are formed, and the biconical antenna is located in the dielectric cylinder and is used to feed the cylindrical polarization conversion array; the biconical antenna is an omnidirectional antenna, and the radiated omnidirectional linearly polarized waves are converted into omnidirectional left-handed circularly polarized waves after passing through the cylindrical polarization conversion array.

[0004] However, the technology has the following problems: it cannot achieve a wider bandwidth while realizing linear-to-circular polarization, it cannot realize the polarization conversion function through the double-layer metasurface, and it does not have better matching characteristics and circular polarization characteristics.

[0005] Based on this, the utility model designs an adjustable phase line to circular polarization converter based on a modified leaf-shaped metasurface to solve the above problems. Utility Model Content

[0006] In view of the above-mentioned shortcomings of the prior art, the utility model provides an adjustable phase line to circular polarization converter based on an improved leaf-shaped metasurface.

[0007] In order to achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] An adjustable phase line to circular polarization converter based on a modified leaf-shaped metasurface, comprising a metal layer and a dielectric layer, wherein the metal layer comprises a top metal patch layer, a second top metal patch layer, an upper ground layer, a stripline layer, a lower ground layer and a lower metal patch layer;

[0009] The dielectric layer includes a first dielectric layer, a second dielectric layer, a third dielectric layer, a fourth dielectric layer and a fifth dielectric layer.

[0010] Furthermore, the top metal patch layer, the first dielectric layer, the second top metal patch layer, the second dielectric layer, the upper ground layer, the third dielectric layer, the stripline layer, the fourth dielectric layer, the lower ground layer, the fifth dielectric layer and the lower metal patch layer are distributed in sequence from top to bottom.

[0011] Furthermore, the top views of the top metal patch layer, the first dielectric layer, the second top metal patch layer, the second dielectric layer, the upper ground layer, the third dielectric layer, the stripline layer, the fourth dielectric layer, the lower ground layer, the fifth dielectric layer and the lower metal patch layer are all square.

[0012] Furthermore, the top metal patch layer and the second top metal patch layer are composed of leaf-shaped super surfaces that are equally distributed, and a gap is opened in the middle of the leaf-shaped metal patches of the top metal patch layer and the second top metal patch layer.

[0013] Furthermore, the upper ground layer and the lower ground layer are respectively engraved with two centrally symmetrical gaps, and the upper ground layer can be regarded as the lower ground layer rotated 90°.

[0014] Furthermore, the strip line layer is composed of two identical and centrally symmetrical strip lines bent at 90° end to end.

[0015] Furthermore, the lower metal patch layer is composed of evenly distributed square metal sheets.

[0016] Furthermore, the shapes of the gap ends of the upper ground layer and the lower ground layer include, but are not limited to, rectangles, sectors, and triangles.

[0017] Furthermore, the stripline layer realizes phase compensation by changing the length of the stripline, and the shape of the matching terminal of the stripline includes but is not limited to a rectangle, and also includes a fan-shaped or a triangle.

[0018] Furthermore, the patch shape of the lower metal patch layer includes but is not limited to a square, and the patch shapes of the top metal patch layer and the second top metal patch layer include a leaf shape and other improved leaf shapes.

[0019] The utility model has the following technical effects:

[0020] 1. The utility model can realize polarization conversion function through a double-layer metasurface, and has better matching characteristics and circular polarization characteristics. While realizing linear-to-circular polarization, the polarization converter is convenient for phase adjustment and can achieve a wider bandwidth. It uses a linear polarization feed source, has low cost and simple structure.

[0021] 2. The utility model has a polarization selection function, only passes X-polarized electromagnetic waves and filters out electromagnetic waves in other directions, uses strip lines as true delay lines to perform phase adjustment and polarization twisting, and can twist X-polarized electromagnetic waves into Y-polarized electromagnetic waves. At the same time, the phase can be adjusted by changing the length of the true delay line. The design is simple and easy to modify, and linear phase can be achieved in a wider frequency band.

[0022] 3. The utility model is designed as an air-fed array antenna unit, which can achieve circular polarization without designing a complicated feeding network, has a simple structure and is convenient to design. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 The utility model is a specific structure of an adjustable phase line to circular polarization converter based on an improved leaf-shaped metasurface;

[0025] Figure 2 It is a schematic diagram of the top metal patch layer of the utility model;

[0026] Figure 3 It is a schematic diagram of the upper grounding layer of the utility model;

[0027] Figure 4 is a schematic diagram of a stripline layer of the utility model;

[0028] Figure 5 It is a schematic diagram of the lower grounding layer of the utility model;

[0029] Figure 6 It is a schematic diagram of the lower metal patch layer of the utility model;

[0030] Figure 7 It is a curve diagram of the amplitude simulation of the electromagnetic wave of the utility model;

[0031] Figure 8 This is a phase simulation curve diagram of the electromagnetic wave of the utility model.

[0032] The numbers in the figure represent:

[0033] 1. Top metal patch layer; 2. First dielectric layer; 3. Second top metal patch layer; 4. Second dielectric layer; 5. Upper ground layer; 6. Third dielectric layer; 7. Stripline layer; 8. Fourth dielectric layer; 9. Lower ground layer; 10. Fifth dielectric layer; 11. Lower metal patch layer. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0035] The utility model is further described below in conjunction with embodiments.

[0036] Example 1

[0037] Please refer to the instruction manual Figure 1-8 , an adjustable phase line to circular polarization converter based on a modified leaf-shaped metasurface, comprising a metal layer and a dielectric layer, wherein the metal layer comprises a top metal patch layer 1, a sub-top metal patch layer 3, an upper ground layer 5, a stripline layer 7, a lower ground layer 9 and a lower metal patch layer 11;

[0038] The dielectric layer uses a standard PCB as a dielectric substrate;

[0039] The dielectric layer includes a first dielectric layer 2 , a second dielectric layer 4 , a third dielectric layer 6 , a fourth dielectric layer 8 and a fifth dielectric layer 10 .

[0040] The electromagnetic wave propagates upward from the lower layer. After the lower metal patch layer 11 receives the electromagnetic wave, it is transmitted to the lower ground layer 9 through the fifth dielectric layer 10. Due to the unique arrangement of the gaps in the lower ground layer 9, it has a polarization selection characteristic, and only electromagnetic waves with one polarization direction can pass through. Assuming that the X-polarized electromagnetic wave passes through the lower ground layer 9 and reaches the stripline layer 7, since the transmission path of the stripline on the stripline layer 7 is bent by 90°, the X-polarization is twisted into Y-polarization, which is just coupled with the gap of the upper ground layer 5 and radiated to the sub-top metal patch layer 3. The sub-top metal patch layer 3 and the top metal patch layer 1 both have polarization conversion characteristics, which can convert linear polarization into circular polarization.

[0041] Example 2

[0042] like Figure 1-8As shown, as a preferred embodiment of the utility model, the top metal patch layer 1, the first dielectric layer 2, the second top metal patch layer 3, the second dielectric layer 4, the upper ground layer 5, the third dielectric layer 6, the stripline layer 7, the fourth dielectric layer 8, the lower ground layer 9, the fifth dielectric layer 10 and the lower metal patch layer 11 are distributed in sequence from top to bottom.

[0043] The top view of the top metal patch layer 1, the first dielectric layer 2, the second top metal patch layer 3, the second dielectric layer 4, the upper ground layer 5, the third dielectric layer 6, the stripline layer 7, the fourth dielectric layer 8, the lower ground layer 9, the fifth dielectric layer 10 and the lower metal patch layer 11 are all square.

[0044] The top metal patch layer 1 and the second top metal patch layer 3 are composed of leaf-shaped super surfaces that are equally distributed. A gap is opened in the middle of the leaf-shaped metal patches of the top metal patch layer 1 and the second top metal patch layer 3.

[0045] The double-layer metasurface structure has a partial reflection function, forming a resonant cavity between the sub-top metal patch layer 3 and the upper ground layer 5. Electromagnetic waves are reflected back and forth between the resonant cavities, and the transmitted electromagnetic waves are superimposed in phase on the other side, thereby greatly improving the performance of the polarization converter;

[0046] At the same time, the utility model improves the common leaf-shaped metasurface layer by slotting a gap in the middle of the leaf-shaped metal patch. This design greatly improves the circular polarization effect of the polarization converter and finally realizes the broadband circular polarization function.

[0047] The upper grounding layer 5 and the lower grounding layer 9 are each engraved with two centrally symmetrical gaps, and the upper grounding layer 5 can be regarded as the lower grounding layer 9 rotated 90°, and the gaps of the upper grounding layer 5 and the lower grounding layer 9 are orthogonally distributed to couple and radiate energy in orthogonal polarization directions.

[0048] To improve the impedance matching effect, both ends of the upper ground layer 5 and the lower ground layer 9 are widened.

[0049] The stripline layer 7 is composed of two identical and centrally symmetrical striplines bent at 90° from head to tail. Both ends of the stripline are widened to accommodate matching terminals. Phase adjustment can be achieved by changing the total length of the stripline.

[0050] The lower metal patch layer 11 is composed of evenly distributed square metal sheets.

[0051] The shapes of the gap ends of the upper ground layer 5 and the lower ground layer 9 include, but are not limited to, rectangles, and also include other shapes such as sectors and triangles.

[0052] The stripline layer 7 achieves phase compensation by changing the length of the stripline. The shape of the matching terminal of the stripline includes but is not limited to a rectangle, and also includes other shapes such as a fan-shaped, a triangle, etc.

[0053] The stripline width mic_w of the stripline layer 7 is [0.01λ, 0.1λ], and the total length of a single stripline in the example shown is l1+l 2+l 3+l4+l5+l 6+l 7+l 8, and its size is [0.1λg, 1.5λg]. The stripline has four identical rectangular terminals at both ends, and their length match_w is [0.01λ, 0.1λ], and their match_l width is [0.01λ, 0.1λ], where λg is the medium wavelength and λ is the free space wavelength. Linear phase modulation can be achieved by adjusting the total length of the stripline.

[0054] The patch shape of the lower metal patch layer 11 includes but is not limited to a square, and the patch shapes of the top metal patch layer 1 and the second top metal patch layer 3 include leaf shapes and other improved leaf shapes.

[0055] The utility model realizes polarization conversion function through a double-layer metasurface, has better matching characteristics and circular polarization characteristics; and uses a strip line as a true delay line to perform phase adjustment and polarization twisting, which can twist the X-polarization direction electromagnetic wave into a Y-polarization electromagnetic wave. At the same time, the phase can be adjusted by changing the length of the true delay line. The design is simple and easy to modify, and linear phase can be achieved in a wider frequency band.

[0056] Example 3

[0057] like Figure 1-8 As shown in the figure, as a preferred embodiment of the utility model, the dielectric constant ε of the dielectric layer is r is [2.2, 6.15], and the thickness is [0.01λ, 0.1λ], where λ is the free space wavelength.

[0058] The side length a of the phase-adjustable line-to-circular polarization converter is [0.4λ, 0.8λ], the side length sur_w of the top metal patch layer 1 and the secondary metal patch layer 3 is [0.1λ, 0.4λ], the patch spacing sur_s is [0.01λ, 0.05λ], the top metal patch layer 1 and the secondary metal patch layer 3 are completely consistent in shape and size, the gap width sl ot_s is [0.001λ, 0.01λ], the radius r is [0.05λ, 0.2λ], the side length sur_w1 of the lower metal patch layer 11 is [0.1λ, 0.4λ], and the patch spacing sur_s1 is [0.01λ, 0.05λ];

[0059] The thickness of the upper ground layer 5 and the lower ground layer 9 is [0.005λ, 0.1λ], the upper gap size sl ot_w1 is [0.04λ, 0.1λ], sl ot_l 1 is [0.02λ, 0.1λ], the length of sl ot_l is [0.06λ, 0.6λ], and the width sl ot_w is [0.02λ, 0.15λ]; where λ is the free space wavelength.

[0060] according to Figure 7 As shown in the figure, the simulation is performed using the fl oquet mode. The impedance matching is actually the reflection coefficient, which represents the amplitude of the electromagnetic wave that is incident in the X-polarization direction and then reflected back in the X-polarization direction; T xx It represents the amplitude of the electromagnetic wave incident in the X-polarization direction and transmitted into the free space along the X direction, T xy It represents the amplitude of the electromagnetic wave incident in the X-polarization direction and transmitted into the free space along the Y direction;

[0061] Combination Figure 8 , and They represent the phase of the electromagnetic wave incident in the X-polarization direction and transmitted in the X-polarization direction, and the phase of the electromagnetic wave incident in the X-polarization direction and transmitted in the Y-polarization direction respectively; and It represents the difference between the former and the latter. It can be seen from the figure that the phase of the electromagnetic wave changes linearly with the frequency, and the incident wave can be successfully decomposed into X and Y polarized waves with a phase difference of 90° after being decomposed by the metasurface. This shows that the polarization converter successfully realizes circular polarization and has a wide phase bandwidth.

[0062] 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 the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An adjustable phase line to circular polarization converter based on a modified leaf-shaped metasurface, comprising a metal layer and a dielectric layer, characterized in that: The metal layer comprises a top metal patch layer (1), a second top metal patch layer (3), an upper ground layer (5), a stripline layer (7), a lower ground layer (9) and a lower metal patch layer (11); The dielectric layer comprises a first dielectric layer (2), a second dielectric layer (4), a third dielectric layer (6), a fourth dielectric layer (8) and a fifth dielectric layer (10).

2. The adjustable phase line-to-circular polarization converter based on the improved leaf-shaped metasurface according to claim 1 is characterized in that: The top metal patch layer (1), the first dielectric layer (2), the second top metal patch layer (3), the second dielectric layer (4), the upper ground layer (5), the third dielectric layer (6), the stripline layer (7), the fourth dielectric layer (8), the lower ground layer (9), the fifth dielectric layer (10) and the lower metal patch layer (11) are arranged in sequence from top to bottom.

3. The adjustable phase line-to-circular polarization converter based on the improved leaf-shaped metasurface according to claim 2 is characterized in that: The top view of the top metal patch layer (1), the first dielectric layer (2), the second top metal patch layer (3), the second dielectric layer (4), the upper ground layer (5), the third dielectric layer (6), the strip line layer (7), the fourth dielectric layer (8), the lower ground layer (9), the fifth dielectric layer (10) and the lower metal patch layer (11) are all square.

4. The adjustable phase line-to-circular polarization converter based on the improved leaf-shaped metasurface according to claim 3 is characterized in that: The top metal patch layer (1) and the second top metal patch layer (3) are composed of leaf-shaped super surfaces that are equally distributed, and a gap is provided in the middle of the leaf-shaped metal patches of the top metal patch layer (1) and the second top metal patch layer (3).

5. The adjustable phase line-to-circular polarization converter based on the improved leaf-shaped metasurface according to claim 4 is characterized in that: The upper grounding layer (5) and the lower grounding layer (9) are each engraved with two centrally symmetrical gaps, and the upper grounding layer (5) can be regarded as the lower grounding layer (9) rotated by 90 degrees.

6. The adjustable phase line-to-circular polarization converter based on the improved leaf-shaped metasurface according to claim 5 is characterized in that: The stripline layer (7) is composed of two identical and centrally symmetrical striplines bent 90 degrees end to end.

7. The adjustable phase line-to-circular polarization converter based on the improved leaf-shaped metasurface according to claim 6 is characterized in that: The lower metal patch layer (11) is composed of evenly distributed square metal sheets.

8. The adjustable phase line-to-circular polarization converter based on the improved leaf-shaped metasurface according to claim 7 is characterized in that: The shapes of the gap ends of the upper ground layer (5) and the lower ground layer (9) include, but are not limited to, rectangles, and also include sectors and triangles.

9. The adjustable phase line-to-circular polarization converter based on the improved leaf-shaped metasurface according to claim 8, characterized in that: The stripline layer (7) achieves phase compensation by changing the length of the stripline, and the matching terminal shape of the stripline includes but is not limited to a rectangle, and also includes a fan shape and a triangle.

10. The adjustable phase line-to-circular polarization converter based on the improved leaf-shaped metasurface according to claim 9, characterized in that: The patch shape of the lower metal patch layer (11) includes, but is not limited to, a square, and the patch shapes of the top metal patch layer (1) and the second top metal patch layer (3) include a leaf shape and a modified leaf shape.

Images