A compact cross orthogonal scanning multi-layer millimeter wave multi-beam array antenna

Abstract

The application discloses a compact cross orthogonal scanning multilayer millimeter wave multi-beam array antenna, which comprises a two-port common-cavity Roofman lens feeding network structure and a common-aperture antenna layer, the two-port common-cavity Roofman lens feeding network structure is located at the bottom layer, and the common-aperture antenna layer is located above the common-cavity Roofman lens feeding network structure; the common-aperture antenna layer comprises a slot antenna layer and a patch antenna layer, the slot antenna layer is located at the bottom layer, and the patch antenna layer is located above the slot antenna layer. The application reduces the echo loss of each port, reduces the reflection of incident waves at the edge port, increases the isolation between the ports and between the two sub-lenses, and improves the working efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of Rotman lens multi-beam antenna, and particularly relates to a compact cross-orthogonal scanning multi-layer millimeter wave multi-beam array antenna. BACKGROUND

[0002] In a wireless communication system, a multi-beam antenna is increasingly becoming an indispensable component. The multi-beam antenna can switch the beam direction along a specific axis. The beam scanning antenna has been applied to various scenarios such as wireless communication, radar and imaging. In recent years, the multi-beam scanning antenna provided with feeding by a circuit type or quasi-optical beam forming network has become an ideal candidate antenna for future B5G / 6G applications.

[0003] In addition to one-dimensional and two-dimensional beam scanning in the field of beam scanning, a kind of orthogonal beam scanning is also noteworthy. The orthogonal beam scanning is realized by orthogonally arranging two one-dimensional beam scanning antennas and simultaneously scanning in the azimuth and elevation planes. It is a two-dimensional planar scanning method. The conventional multi-beam antenna generally realizes one-dimensional linear scanning. The realization of orthogonal scanning requires the beam to have a certain pointing angle in the elevation plane and the horizontal plane. Therefore, new requirements are put forward for the design of the feeding network. The integration of the orthogonal scanning system has thus become a big problem. SUMMARY

[0004] The application aims to provide a compact cross-orthogonal scanning multi-layer millimeter wave multi-beam array antenna, which reduces the return loss of each port, reduces the reflection of incident waves at the edge port, increases the isolation between ports and between two sub-lenses, and improves the working efficiency.

[0005] In order to achieve the purpose of the application, the application provides a compact cross-orthogonal scanning multi-layer millimeter wave multi-beam array antenna, which comprises a dual-port common-cavity Rotman lens feeding network structure and a common-aperture antenna layer. The dual-port common-cavity Rotman lens feeding network structure is located at the bottom layer, and the common-aperture antenna layer is located above the common-cavity Rotman lens feeding network structure.

[0006] The common-aperture antenna layer comprises a slot antenna layer and a patch antenna layer. The slot antenna layer is located at the bottom layer, and the patch antenna layer is located above the slot antenna layer.

[0007] The double-port common-cavity Rotman lens feeding network structure comprises a power-division type double-port feeding structure, a common-cavity Rotman lens structure, a double-layer transition structure and a three-layer transition structure; the power-division type double-port feeding structure forms a feeding source profile of the common-cavity Rotman lens; the common-cavity Rotman lens structure is composed of two orthogonal Rotman lens structures; the double-layer transition structure is located on an inner array profile of the common-cavity Rotman lens, and the three-layer transition structure is located on another inner array profile of the common-cavity Rotman lens, and is used for realizing energy propagation between different layers.

[0008] The slot antenna layer comprises a slot antenna, a slot antenna array unit and an offset hole; the slot antenna is a rectangular slot and is used for radiating energy outward; the slot antenna array unit is formed by arraying ten slot antennas, and ten slot antenna array units are arranged laterally; and the offset hole is located in a cut resonant cavity in a substrate integrated waveguide.

[0009] The patch antenna layer comprises a microstrip line antenna, a radiation cavity and a horn-shaped transition structure; the microstrip line antennas are arranged longitudinally, and ten microstrip line antennas are arranged in an array; the radiation cavity is embedded in the microstrip line antennas in a 10*10 array; and the horn-shaped transition structures are located at input ends of the microstrip line antennas, and there are ten horn-shaped transition structures, which are used for transitioning energy from the substrate integrated waveguide to the microstrip line.

[0010] Compared with the prior art, the present application has the following advantages: (1) the present application constructs a power-division type double-port excitation, and a double-port feeding mode is adopted at an input port, which replaces a horn-type transition in a traditional structure, effectively improves isolation between input ports, improves concentration of incident waves by double-port excitation, reduces scattering of electromagnetic energy in a cavity, thereby reducing coupling between two sub-lenses, improving working efficiency of a feeding network and improving isolation between ports of the feeding network, and reducing insertion loss; (2) the present application proposes a new radiation assembly, integrates a patch antenna array and a slot antenna array into a common aperture, forms a new common aperture antenna, makes the whole array antenna arrangement compact, and forms a two-dimensional planar adjustable scanning beam in orthogonal radiation area directions; (3) the present application realizes effective integration of a feeding network and a radiation aperture by using multi-layer slot coupling, separates output ports of two sub-networks through multi-layer conversion, hides the whole feeding network under the radiation aperture through slot coupling design, thereby forming a compact orthogonal scanning system, improving system integration and reducing total area of a working system.

[0011] To make the function and structure of the present application clearer, the function and structure of the present application are further described below in combination with the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0012] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0013] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0014] Figure 2 This is a schematic diagram of the dual-port common cavity Rotman lens feeding network structure of the present invention;

[0015] Figure 3 This is a schematic diagram of the slot antenna layer structure of the present invention, wherein (a) is a schematic diagram of the entire layer structure and (b) is a schematic diagram of the array unit structure;

[0016] Figure 4 This is a schematic diagram of the patch antenna layer structure of the present invention, wherein (a) is a schematic diagram of the entire layer structure and (b) is a schematic diagram of the array unit structure;

[0017] Figure 5 This is a schematic diagram of the overall structure of the common aperture antenna of the present invention;

[0018] Figure 6 This is a comparison diagram of the electric field distribution caused by the dual-port excitation of the present invention and the single-port excitation, wherein (a) is the electric field distribution of the dual-port excitation and (b) is the electric field distribution of the single-port excitation.

[0019] Figure 7 This is a schematic diagram of the design principle of the present invention;

[0020] Figure 8 This is a comparison chart of the reflection coefficients in the simulation and test of the present invention, where (a) is the reflection coefficient when ports #1 to #5 are fed, and (b) is the reflection coefficient when ports #6 to #10 are fed.

[0021] Figure 9 This is a schematic diagram of the antenna radiation main polarization scanning angle and gain of the present invention, wherein (a) is the radiation situation of ports #1 to #5, and (b) is the radiation situation of ports #6 to #10.

[0022] The figures are labeled as follows: 1. Dual-port common-cavity Rotman lens feed network structure; 2. Common-aperture antenna layer; 3. Slot antenna layer; 4. Patch antenna layer; 1-1. Power-divided dual-port feed structure; 1-2. Common-cavity Rotman lens structure; 1-3. Two-layer transition structure; 1-4. Three-layer transition structure; 3-1. Slot antenna; 3-2. Slot antenna array element; 3-3. Offset aperture; 4-1. Microstrip line antenna; 4-2. Radiation cavity; 4-3. Horn-shaped transition structure. Detailed Implementation

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0024] The compact cross-orthogonal scanning multi-layer millimeter wave multi-beam array antenna comprises a two-port common-cavity Roofman lens feeding network structure 1 and a common-aperture antenna layer 2, the two-port common-cavity Roofman lens feeding network structure 1 is located at the bottom layer, and the common-aperture antenna layer 2 is located directly above the two-port common-cavity Roofman lens feeding network structure 1.

[0025] The common-aperture antenna layer 2 comprises a slot antenna layer 3 and a patch antenna layer 4, the slot antenna layer 3 is located at the bottom layer, and the patch antenna layer 4 is located directly above the slot antenna layer 3; the whole working system has three layers, and electrical interconnection is realized in the vertical direction.

[0026] In combination with Figure 2 , the two-port common-cavity Roofman lens feeding network structure 1 is a first layer antenna layer, comprising a power-division type two-port feeding structure 1-1, a common-cavity Roofman lens structure 1-2, a double-layer transition structure 1-3 and a three-layer transition structure 1-4; the power-division type two-port feeding structure 1-1 constitutes a feeding source contour of the common-cavity Roofman lens 1-2, replaces a traditional single port and divides the energy of an input port into two parts; the common-cavity Roofman lens structure 1-2 is composed of two orthogonal Roofman lens structures, the center working frequency is set to 28 GHz, the focal length F of the Roofman lens is 65 mm, and the focal ratio is 1.1; the double-layer transition structure 1-3 is located on an inner array contour of the common-cavity Roofman lens, and the three-layer transition structure 1-4 is located on another inner array contour of the common-cavity Roofman lens, double-layer and three-layer transition layers are respectively designed above different output ports of the two orthogonal groups of sub-lenses, each transition layer is composed of a metalized via hole array with a diameter of 0.508 mm and a spacing of 0.8 mm and a slot at the bottom, is used for isolating transmission channels between different layers and is used for realizing the propagation of energy between different layers.

[0027] In combination with Figure 3 (a), the slot antenna layer 3 is a second layer antenna layer, comprising a slot antenna 3-1, a slot antenna array unit 3-2 and an offset hole 3-3; the slot antenna 3-1 is a rectangular slot, the size of the slot is 4.38*0.6 mm and is used for radiating energy outward; the slot antenna array unit 3-2 is formed by arraying ten slot antennas 3-1, ten slot antennas 3-1 are horizontally and uniformly arranged at equal intervals, the interval is 5.40 mm; the offset hole 3-3 is located in a cut resonant cavity in a substrate integrated waveguide; in combination withFigure 3 (b), the structure parameters of the slot antenna layer 3 are as follows: the width d1 of the slot antenna array unit is 5.40, the length d2 of the slot antenna slot is 4.38, the length d3 of the offset hole from the array unit boundary is 0.74, the distance d4 between the slot antenna slots is 5.40, the width d5 of the slot antenna slot is 0.60, the length d6 of the slot antenna unit from the array unit edge is 4.91, the length d7 of the offset hole from the array unit boundary is 3.45, and the unit is mm. There is a row of transition holes with a diameter of 0.508 mm and a spacing of 0.8 mm below to guide the energy to be coupled upward.

[0028] In combination Figure 4 (a), the patch antenna layer 4 is the third layer antenna layer, which comprises a microstrip line antenna 4-1, a radiation cavity 4-2, and a horn-shaped transition structure 4-3; the microstrip line antennas 4-1 are arranged longitudinally and equidistantly with a distance of 5.4 mm, and ten microstrip line antennas 4-1 are arranged; the radiation cavities 4-2 are embedded in the microstrip line antennas 4-1 in a 10*10 array, the radiation cavities 4-2 are metalized rectangular through holes with a size of 4.38 mm*0.6 mm, the copper thickness inside the through hole is 0.05 mm, and the spacing between each rectangular through hole and the adjacent one is 5.4 mm; the horn-shaped transition structures 4-3 are located at the input ends of the microstrip line antennas 4-1, and there are ten horn-shaped transition structures 4-3, the angle of the horn-shaped transition structure 4-3 is 22.5°, and the horn-shaped transition structure 4-3 is used for the transition of energy from the substrate integrated waveguide to the microstrip line; in combination Figure 4 (b), the structure parameters of the patch antenna layer 4 are as follows: the line width d8 of the microstrip line antenna is 0.40, the length d9 of the microstrip line antenna node is 2.00, the distance d10 between the microstrip line antenna nodes is 5.40, the width d11 of the microstrip line antenna node is 0.60, the width d12 of the microstrip line antenna is 1.90, the line length d13 of the microstrip line antenna is 2.40, and the length d14 of the tail unit of the microstrip line antenna is 3.80, the unit is mm; in combination Figure 5 .

[0029] In combination Figure 1 After the three-layer structure composed of the dual-port co-cavity Rotman lens feed network structure 1, the slot antenna layer 3, and the patch antenna layer 4 is arranged in corresponding order, the overall size is 114.6 mm*114.6 mm, and the carbon fiber plate is used for compression assembly, wherein #1 to #10 respectively represent ten input ports of the system, #3 and #8 are the center ports of the working system, the carbon fiber plate with a thickness of 0.2 mm is used for compression installation, the three-layer structure is coupled through multiple layers of pores to realize electrical interconnection between different layers, and the second layer and the third layer jointly compose a co-aperture antenna array. Taking the center port as an example, the working principle of the antenna system is as follows: in combination Figure 7Taking the central ports #3 and #8 as examples, when energy is input from the central ports, power is fed from the two central ports, and the energy is coupled upward along the common cavity Rotman lens to achieve electrical interconnection between different layers.

[0030] Furthermore, the substrate material of the three-layer structure is Rogers RT / duroid 5880, and the thickness is 0.508mm.

[0031] Furthermore, the metal structures at the top and bottom of the three-layer substrate are made of copper with a thickness of 0.035 mm.

[0032] This invention, based on substrate integrated waveguide technology, orthogonally aligns two Rotman subnetworks and introduces a novel dual-port feeding method at the feed arc. Then, it integrates a patch antenna lens array and a slot antenna array into a single common aperture, with the input ports orthogonally arranged and vertically compatible with the dual-port common-cavity Rotman lens. Slot coupling combines the dual-port common-cavity Rotman lens and the common aperture antenna array, allowing for different beam pointing by switching different input ports. This results in a compact, multi-layered, cross-shaped orthogonal scanning multi-beam antenna capable of beam switching along two orthogonal planes in the millimeter-wave spectrum.

[0033] Combination Figure 6 (a) and Figure 6 (b) A comparison of the electric field distribution inside the cavity of the common cavity Rotman based on power-division dual-port feeding and the traditional common cavity Rotman. It can be clearly seen that dual-port feeding effectively concentrates the incident wave, reduces the loss of electromagnetic energy in the cavity, and improves the return loss.

[0034] Combination Figure 8 The reflection coefficient S obtained from simulation and testing 11 To S 99 S represents the return loss from port #1 to port #9 input. 00 This represents the return loss input from port #10, in dB. Figure 8 (a) and Figure 8 (b) It can be seen that from 27.8 GHz to 28.2 GHz, the reflection coefficient results of ports #1 to #1O are all less than -10 dB.

[0035] Combination Figure 9 The simulation and measurement of the main polarization scan angle and gain of the ten input ports, among which Figure 9 (a) represents the main polarization intensities corresponding to #1 to #5, with a coverage angle of -29.4° to 29.4° on the horizontal plane; Figure 9(b) represents the principal polarization intensity of #6-#10 corresponding to the coverage angle of 59.9° to 149.9° in the elevation plane, and by switching different input ports, the switching of different scanning beams in the orthogonal direction can be realized.

[0036] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another, without necessarily requiring or implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0037] While the embodiments of the application have been illustrated and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made therein without departing from the spirit and scope of the application, which is defined by the appended claims and their equivalents.

Claims

1. A compact cross orthogonal scanning multi-layer millimeter wave multi-beam array antenna, characterized in that, The application relates to a dual-port common-cavity Rotman lens feeding network structure (1), a common-aperture antenna layer (2), the dual-port common-cavity Rotman lens feeding network structure (1) is located at the bottom layer, and the common-aperture antenna layer (2) is located above the dual-port common-cavity Rotman lens feeding network structure (1); The common-aperture antenna layer (2) comprises a slot antenna layer (3) and a patch antenna layer (4), the slot antenna layer (3) is located at the bottom layer, and the patch antenna layer (4) is located above the slot antenna layer (3); The dual-port common-cavity Rotman lens feeding network structure (1) comprises a power-division type dual-port feeding structure (1-1), a common-cavity Rotman lens structure (1-2), a double-layer transition structure (1-3) and a three-layer transition structure (1-4); the power-division type dual-port feeding structure (1-1) forms a feeding source profile of the common-cavity Rotman lens structure (1-2); the common-cavity Rotman lens structure (1-2) is composed of two orthogonal Rotman lens structures; the double-layer transition structure (1-3) is located on an inner array profile of the common-cavity Rotman lens, and the three-layer transition structure (1-4) is located on another inner array profile of the common-cavity Rotman lens, and is used for realizing energy transmission between different layers; The slot antenna layer (3) comprises a slot antenna (3-1), a slot antenna array unit (3-2) and an offset hole (3-3); the slot antenna (3-1) is a rectangular slot, and is used for radiating energy outward; the slot antenna array unit (3-2) is formed by arraying ten slot antennas (3-1), and ten slot antenna array units (3-2) are horizontally arranged; and the offset hole (3-3) is located in a substrate integrated waveguide and cuts a resonant cavity. The patch antenna layer (4) comprises a microstrip line antenna (4-1), a radiation cavity (4-2) and a horn-shaped transition structure (4-3); the microstrip line antenna (4-1) is longitudinally arranged, and ten microstrip line antennas (4-1) are arranged in parallel; the radiation cavity (4-2) is embedded in the microstrip line antenna (4-1) in a 10*10 array; and the horn-shaped transition structure (4-3) is located at the input end of the microstrip line antenna (4-1), and there are ten horn-shaped transition structures (4-3) in total, and the horn-shaped transition structures (4-3) are used for transitioning energy from a substrate integrated waveguide to a microstrip line.

2. The compact cross orthogonal scanning multi-layer millimeter-wave multi-beam array antenna according to claim 1, wherein, The structural parameters of the slot antenna layer (3) are as follows: the width d1 of the slot antenna array unit is 5.40 mm, the length d2 of the slot antenna slot is 4.38 mm, the length d3 of the offset hole from the array unit boundary is 0.74 mm, the distance d4 between the slot antenna slots is 5.40 mm, the width d5 of the slot antenna slot is 0.60 mm, the length d6 of the slot antenna unit from the array unit edge is 4.91 mm, and the length d7 of the offset hole from the array unit boundary is 3.45 mm.

3. The compact cross orthogonal scanning multi-layer millimeter-wave multi-beam array antenna according to claim 1, wherein, The structural parameters of the patch antenna layer (4) are as follows: the line width of the microstrip line antenna is d8=0.40, the length of the microstrip line antenna node is d9=2.00, the distance between the microstrip line antenna nodes is d10=5.40, the width of the microstrip line antenna node is d11=0.60, the width of the microstrip line antenna is d12=1.90, the line length of the microstrip line antenna is d13=2.40, and the length of the tail unit of the microstrip line antenna is d14=3.80, which are all in mm.

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