Millimeter-wave folded transmissive array antenna

Abstract

The present invention discloses a millimeter-wave folded transmissive array antenna, which relates to the technical field of antennas. The antenna includes a transmissive structure, a polarization conversion structure, and a feed source. The transmissive structure is located above the polarization conversion structure, and the feed source is located in the middle of the polarization conversion structure. The transmissive structure includes a plurality of transmissive units connected to each other, and the transmissive units are used to realize the functions of phase modulation and transmission of a single linearly polarized wave. The polarization conversion structure includes a plurality of polarization conversion units connected to each other, and the polarization conversion units are used to realize the function of converting a linearly polarized wave. The feed source is a rectangular open waveguide, and the feed source provides energy for the folded transmissive array antenna. The antenna can improve the gain, reduce the complexity of unit design, and improve the polarization conversion efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of antennas, and in particular to a millimeter-wave folded transmissive array antenna based on double-layer magnetoelectric dipole phase modulation. Background Art

[0002] With the growth of communication demands in modern society, the new generation of wireless communication systems has developed rapidly. At the same time, people's requirements for communication technologies are getting higher and higher, and the demand for high-quality and high-efficiency antennas is also stronger. Modern communication antennas need to meet various indicators such as size, bandwidth, and gain. Since the low-frequency band has become very crowded in the development of wireless communication, it is necessary to increase the operating frequency of the antenna. Therefore, the millimeter-wave band is adopted in the present invention. However, in the application of millimeter waves, the too small wavelength and the too high tolerance requirements will cause losses and be harmful to the radiation pattern. The present invention adopts a transmissive array structure to improve the efficiency.

[0003] The transmissive array antenna is a new type of high-gain antenna. The spherical wave emitted by its feed source irradiates the planar transmissive array surface. The paths to each unit on the array surface are different, and there is a certain phase difference between each unit. By controlling the phase shift of each unit on the array surface, the electromagnetic wave forms a in-phase wave after passing through the transmissive array surface, thereby realizing a high-gain beam. The adopted space feeding method eliminates the loss brought by the feeding network and improves the radiation efficiency of the antenna. Moreover, the feed source and the outgoing beam of the transmissive array are arranged on both sides of the transmissive array surface, and there is no feed source blocking effect of the reflective array. However, the introduction of the air-feed form results in too high a system profile. Compared with the traditional transmissive array antenna, the folded transmissive array structure avoids the system complexity of the transmissive array and has a unique low-profile advantage. Summary of the Invention

[0004] The technical problem to be solved by the present invention is how to provide a millimeter-wave folded transmissive array antenna that can improve the gain, reduce the complexity of unit design, and improve the polarization conversion efficiency.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is: a millimeter-wave folded transmissive array antenna, characterized in that: it includes a transmissive structure, a polarization conversion structure, and a feed source. The transmissive structure is located above the polarization conversion structure, the feed source is located in the middle of the polarization conversion structure. The transmissive structure includes a plurality of transmissive units connected together, and the transmissive units are used to realize the functions of phase modulation and transmission of a single linearly polarized wave; the polarization conversion structure includes a plurality of polarization conversion units connected together, and the polarization conversion units are used to realize the function of converting a linearly polarized wave; the feed source is a rectangular open waveguide, and the feed source provides energy for the folded transmissive array antenna.

[0006] A further technical solution lies in that: the transmission unit includes a first metal layer, a first dielectric layer, and a second metal layer. The structure of the first metal layer is the same as that of the first metal layer. The first metal layer is located on the upper surface of the first dielectric layer, and the second metal layer is located on the lower surface of the first dielectric layer. The first metal layer and the second metal layer are connected together through metallized vias located within the first dielectric layer.

[0007] A further technical solution lies in that: four rectangular slots are formed on the first metal layer. The rectangular slots are arranged in pairs opposite to each other, and the angle between the rectangular slots is 90°. The rectangular slots do not connect to each other. A number of square notches communicating with them are formed on both sides along the opposite long sides of the rectangular slots. The first metal layer and the second metal layer having the rectangular slots and the square notches constitute a magnetoelectric dipole, and the phase is adjusted by changing its size. The square notches are to increase the current flow path, thereby reducing the unit size.

[0008] Preferably, four metallized vias are provided, and the metallized vias are located between the rectangular slots.

[0009] A further technical solution lies in that: the transmission unit further includes a third metal layer located below the second metal layer. The third layer is a plurality of mutually parallel metal lines, which are used to realize the screening of the polarization direction, ensure that the linear polarization along the x direction can pass through while the linear polarization along the y direction is reflected back, and constitute a partial reflection surface.

[0010] A further technical solution lies in that: the polarization conversion unit includes a fourth metal layer, a second dielectric layer, and a fifth metal layer. The fourth metal layer is located on the upper surface of the second dielectric layer, and the fifth metal layer is located on the lower surface of the second dielectric layer.

[0011] A further technical solution lies in that: the fourth metal sheet adopts a butterfly-shaped asymmetric structure, which is used to convert the incident linearly polarized wave in the x direction into a linearly polarized wave in the y direction; the fifth metal sheet is a metal floor, and a slot is formed on the polarization conversion unit located in the middle of the transmitarray antenna, and the feed source is located within the slot.

[0012] Preferably, the thicknesses of the first dielectric layer and the second dielectric layer are 0.1λ and 0.15λ respectively, and the dielectric constant εr is the F4B material with a value of 2.64. The side length p1 of the transmission unit is 0.43λ, and the side length p2 of the polarization conversion unit is 0.5λ.

[0013] Preferably, 20×20 transmission units are provided, and 16×16 polarization conversion units are provided.

[0014] Preferably, the aperture size of the folded transmissive array antenna is 8.6λ × 8.6λ, the realized radiation main lobe width is 7°, and the sidelobe level is -24 dB.

[0015] The beneficial effects produced by adopting the above technical solutions are as follows: 1) The present invention adopts the structure of a transmissive array. By controlling the phase shift of each transmissive unit on the transmissive array surface, electromagnetic waves form in-phase waves after passing through the transmissive array surface, thereby achieving high gain;

[0016] 2) The transmissive unit of the present invention is etched with a square notch, reducing the size of the phase modulation unit of the antenna and realizing the characteristic of miniaturization;

[0017] 3) The present invention adopts the structure of a double-layer coupled magnetoelectric dipole, achieving a phase modulation performance of 310° with only two layers of structure, greatly reducing the number of layers of the structure and meeting the design requirements of low profile and simple structure;

[0018] 4) The present invention adopts a butterfly-shaped asymmetric structure, having a high polarization conversion efficiency and meeting the design requirements of simple structure;

[0019] 5) The feed source of the present invention adopts a rectangular aperture waveguide, having small conductor loss and dielectric loss, large power capacity, no radiation loss, simple structure, and being easy to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0021] Fig. 1a is a schematic exploded view of the millimeter-wave folded transmissive array antenna of the present invention;

[0022] Figure 1b is a schematic structural diagram of the transmissive unit in the antenna according to an embodiment of the present invention;

[0023] Figure 1c is a schematic structural diagram of the polarization conversion unit in the antenna according to an embodiment of the present invention;

[0024] Figure 1d is a schematic structural diagram of the feed source in the antenna according to an embodiment of the present invention;

[0025] Fig. 2 is a phase and amplitude curve diagram of the transmissive unit in the antenna according to an embodiment of the present invention;

[0026] Figure 3 is a polarization conversion curve diagram of the polarization conversion unit in the antenna according to an embodiment of the present invention;

[0027] Figure 4 is a reflection coefficient amplitude curve diagram of the feed source in the antenna according to an embodiment of the present invention;

[0028] Figure 5 This is the E-plane normalized radiation pattern of the antenna at 75 GHz according to the embodiment of the present invention;

[0029] Wherein: 1. The first metal layer; 2. The first dielectric layer; 3. Metallized vias; 4. The second metal layer; 5. The third metal layer; 6. The fourth metal layer; 7. The second dielectric layer; 8. The fifth metal layer; 9. Feed; 10. Transmission structure; 11. Polarization conversion structure; 111. Rectangular slot; 112. Square notch. Detailed implementation manners

[0030] Next, with reference to the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0032] Generally, as Figure 1a shown, the embodiment of the present invention discloses a millimeter-wave folded transmissive array antenna. Preferably, the aperture size of the folded transmissive array antenna is 8.6λ × 8.6λ. The antenna includes a transmission structure 10, a polarization conversion structure 11, and a feed 9. The transmission structure 10 is located above the polarization conversion structure 11, and the feed 9 is located in the middle of the polarization conversion structure 11. The transmission structure 10 includes a plurality of transmission units connected together, and the transmission units are used to realize the functions of phase modulation and transmission of a single linearly polarized wave; the polarization conversion structure 11 includes a plurality of polarization conversion units connected together, and the polarization conversion units are used to realize the function of converting a linearly polarized wave; the feed 9 is a rectangular open waveguide, and the feed provides energy for the folded transmissive array antenna. Preferably, the transmission structure 10 is composed of 20 × 20 transmission units according to a two-dimensional periodic law to realize the functions of phase modulation and transmission of a single linearly polarized wave; the polarization conversion structure 11 is composed of 16 × 16 polarization conversion units and a metal ground according to a two-dimensional periodic law to realize the function of converting a linearly polarized wave;

[0033] Preferably, the spacing p1 between the transmission units is 0.43λ. Further, as Figure 1bAs shown, the transmission unit includes a first metal layer 1, a first dielectric layer 2, and a second metal layer 4. The structure of the first metal layer 1 is the same as that of the second metal layer 4. The first metal layer 1 is located on the upper surface of the first dielectric layer 2, and the second metal layer 4 is located on the lower surface of the first dielectric layer 2. The first metal layer 1 and the second metal layer 4 are connected together through metallized vias 3 located within the first dielectric layer 2.

[0034] Furthermore, as Figure 1b shown, four rectangular slots 111 are formed on the first metal layer 1. The rectangular slots 111 are arranged in pairs opposite to each other, and the angle between the rectangular slots 111 and the rectangular slots 111 is 90°. The rectangular slots 111 are not connected to each other. A number of square notches 112 communicating with them are formed on both sides along the opposite long sides of the rectangular slots 111. The first metal layer 1 and the second metal layer 4 having the rectangular slots 111 and the square notches 112 form a magnetoelectric dipole, and the phase is adjusted by changing its size. The square notches 112 are for increasing the current flow path, thereby reducing the unit size. Four metallized vias 3 are provided, and the metallized vias 3 are located between the rectangular slots 111.

[0035] Furthermore, as Figure 1b shown, the transmission unit further includes a third metal layer 5 located on the lower side of the second metal layer 4. The third metal layer 5 is a plurality of parallel metal lines, which are used to realize the screening of the polarization direction, ensure that the linear polarization along the x direction can pass through while the linear polarization along the y direction is reflected back, and form a partial reflection surface.

[0036] Preferably, the spacing p2 between the polarization conversion units is 0.5λ. Further, as Figure 1c shown, the polarization conversion unit includes a fourth metal layer 6, a second dielectric layer 7, and a fifth metal layer 8. The fourth metal layer 6 is located on the upper surface of the second dielectric layer 7, and the fifth metal layer 8 is located on the lower surface of the second dielectric layer 7. The fourth metal layer 6 adopts a butterfly-shaped asymmetric structure, which is used to convert the incident linearly polarized wave in the x direction into a linearly polarized wave in the y direction; the fifth metal layer 8 is a metal floor, and a slot is formed on the polarization conversion unit located in the middle of the transmission array antenna, and the feed source 9 is located within the slot.

[0037] Figure 2 is the phase and amplitude curve diagram of the transmission unit in the antenna according to the embodiment of the present invention. It can be seen that the size change range of the square patch of the transmission unit is 0.2525λ - 0.3875λ, its phase adjustment range is 116° - 197°, and the amplitude is greater than 0.8.

[0038] Figure 3 is the polarization conversion curve diagram of the polarization conversion unit in the antenna of the present invention. It can be seen that the x-polarization amplitude of the reflection of its polarization conversion unit is higher than -1 dB in the frequency band of 60.6 - 89.8 GHz; the y-polarization is lower than -10 dB in the frequency range of 63.0 - 87.8 GHz; the operating frequency band of the unit is 60.6 - 87.8 GHz;

[0039] Figure 4 is the amplitude curve diagram of the feed reflection coefficient of the millimeter-wave folded transmissive array antenna based on the double-layer magnetoelectric dipole phase modulation of the present invention. It can be seen that the amplitude of the reflection coefficient of the feed is lower than -55 dB;

[0040] Figure 5 is the E-plane normalized radiation pattern of the millimeter-wave folded transmissive array antenna based on the double-layer magnetoelectric dipole phase modulation of the present invention at 75 GHz. It can be seen that the 3dB beamwidth of the millimeter-wave folded transmissive array antenna based on the double-layer magnetoelectric dipole phase modulation is 7°, and its side lobe level is lower than -24 dB; it can be seen that it has a good radiation pattern at the operating frequency point.

[0041] As can be seen from the above, the millimeter-wave folded transmissive array antenna based on the double-layer magnetoelectric dipole phase modulation of the present invention has the characteristics of high gain, low side lobes, low loss, miniaturization and simple structure.

Claims

1. A millimeter-wave folded transmissive array antenna, Characterized in that: It includes a transmissive structure (10), a polarization conversion structure (11), and a feed source (9). The transmissive structure (10) is located above the polarization conversion structure (11), the feed source (9) is located in the middle of the polarization conversion structure (11), the transmissive structure (10) includes a plurality of transmissive units connected to each other, and the transmissive units are used to realize the functions of phase modulation and transmission of a single linearly polarized wave; the polarization conversion structure (11) includes a plurality of polarization conversion units connected to each other, and the polarization conversion units are used to realize the function of converting a linearly polarized wave; the feed source (9) is a rectangular open waveguide, and energy is provided to the folded transmissive array antenna through the feed source; The transmissive unit includes a first metal layer (1), a first dielectric layer (2), and a second metal layer (4). The structure of the first metal layer (1) is the same as that of the second metal layer (4). The first metal layer (1) is located on the upper surface of the first dielectric layer (2), the second metal layer (4) is located on the lower surface of the first dielectric layer (2), and the first metal layer (1) and the second metal layer (4) are connected to each other through metallized vias (3) located in the first dielectric layer (2); The polarization conversion unit includes a fourth metal layer (6), a second dielectric layer (7), and a fifth metal layer (8). The fourth metal layer (6) is located on the upper surface of the second dielectric layer (7), and the fifth metal layer (8) is located on the lower surface of the second dielectric layer (7).

2. The millimeter-wave folded transmissive array antenna according to claim 1, Characterized in that: Four rectangular slots (111) are formed on the first metal layer (1). The rectangular slots (111) are arranged in pairs opposite to each other, and the angle between the rectangular slots (111) is 90°. The rectangular slots (111) are not connected to each other. A plurality of square notches (112) communicating with them are formed on both sides of the opposite long sides of the rectangular slots (111). The first metal layer (1) and the second metal layer (4) with rectangular slots (111) and square notches (112) form a magnetoelectric dipole, and the phase is adjusted by changing its size. The square notches (112) are used to increase the current flow path, thereby reducing the unit size.

3. The millimeter-wave folded transmissive array antenna according to claim 1, Characterized in that: Four metallized vias (3) are provided, and the metallized vias (3) are located between the rectangular slots (111).

4. The millimeter-wave folded transmissive array antenna according to claim 1, Characterized in that: The transmissive unit further includes a third metal layer (5) located below the second metal layer (4). The third metal layer (5) is a plurality of mutually parallel metal lines, which are used to screen the polarization direction, ensure that the linearly polarized wave along the x direction can pass through while the linearly polarized wave along the y direction is reflected back, and form a partial reflection surface.

5. The millimeter-wave folded transmissive array antenna according to claim 1, Characterized in that: The fourth metal layer (6) adopts a butterfly-shaped asymmetric structure for converting an incident linearly polarized wave in the x direction into a linearly polarized wave in the y direction; the fifth metal layer (8) is a metal floor, and a slot is formed on the polarization conversion unit in the middle of the transmissive array antenna, and the feed source (9) is located in the slot.

6. The millimeter-wave folded transmissive array antenna according to claim 1, characterized in that: the thicknesses of the first dielectric layer (2) and the second dielectric layer (7) are 0.1λ and 0.15λ respectively, and they are made of F4B material with a relative dielectric constant εr of 2.

64. The side length p1 of the transmissive unit is 0.43λ, and the side length p2 of the polarization conversion unit is 0.5λ.

7. The millimeter-wave folded transmissive array antenna according to claim 1, characterized in that: 20×20 transmissive units are provided, and 16×16 polarization conversion units are provided.

8. The millimeter-wave folded transmissive array antenna according to claim 1, characterized in that: the aperture size of the folded transmissive array antenna is 8.6λ × 8.6λ, the realized radiation main lobe width is 7°, and the side lobe level is -24 dB.

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