A broadband circularly polarized dielectric transmit array antenna with high aperture efficiency

Abstract

The application provides a broadband circularly polarized dielectric transmission array antenna with high aperture efficiency, relates to the field of microwave antennas and arrays, and meets the demand of wireless communication and radar detection for high gain and high directivity beam, and the array is composed of a core dielectric layer, a gradually changing impedance matching layer and a connecting layer. By adjusting the structure of the core dielectric layer and the gradually changing impedance matching layer of the unit, a dielectric unit with broadband and polarization conversion characteristics is obtained, on the basis of which, six dielectric units with different transmission phases are obtained by adjusting the geometric shape, and a circularly polarized transmission array antenna is formed by using 384 dielectric unit structures, so that a new method for designing a broadband polarizer and improving the aperture efficiency of the array is provided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microwave antennas and arrays, in particular to a broadband circularly polarized dielectric transmission array antenna with high aperture efficiency. BACKGROUND

[0002] In today's rapidly developing wireless communication technology, antennas serve as the bridge between electromagnetic waves and electrical signals, and their performance directly affects the efficiency and quality of communication systems. Circularly polarized high-aperture-efficiency antennas, with their unique advantages and outstanding performance, play an important role in satellite communication, radar detection, radio frequency identification, and other fields. Circularly polarized waves have an electric field vector that rotates at a constant angular velocity in the direction of propagation, exhibiting strong anti-multipath interference capability, no need for strict alignment of transmitting and receiving antennas, and suitability for mobile communication. Aperture efficiency, as a key indicator of antenna radiation capability, high aperture efficiency means that the antenna can more effectively convert input power into radiated power, thereby improving system performance.

[0003] Circularly polarized high-aperture-efficiency antennas combine the advantages of circular polarization and high aperture efficiency, enabling efficient and stable wireless signal transmission and meeting the urgent demand for high-performance antennas in modern wireless communication systems. In recent years, with the advent of new materials and new technologies, research and application of circularly polarized high-aperture-efficiency antennas have made significant progress, with their performance continuously improving and their application fields continuously expanding. SUMMARY

[0004] Technical problem: The purpose of the present application is to realize a broadband circularly polarized dielectric transmission array with high aperture efficiency to meet the urgent demand for high-performance antennas in modern wireless communication systems.

[0005] Technical solution: A broadband circularly polarized dielectric transmission array antenna with high aperture efficiency according to the present application is composed of 384 dielectric unit structures with six different transmission phases arranged in a circular aperture; the six different transmission phase dielectric units are: first dielectric unit, second dielectric unit, third dielectric unit, fourth dielectric unit, fifth dielectric unit, and sixth dielectric unit, corresponding to main polarization transmission phases of 0°, 60°, 120°, 180°, 240°, and 300°, respectively; the six different transmission phase dielectric units are six polarization conversion phase shift units, periodically distributed on the circular aperture of the planar dielectric transmission array to form a phase distribution of the target directional focusing beam, so that the phase difference between the two orthogonal linearly polarized waves is 90°, realizing the conversion of linearly polarized waves to circularly polarized waves.

[0006] The 384 different transmission phase medium units are arranged on a circular aperture transmission array as follows: two rows of sixth medium units are arranged in a cross transverse direction and two rows of sixth medium units are arranged in a longitudinal direction at a central position; fifth medium units are arranged in sequence at the outer periphery of the sixth medium units arranged in the transverse and longitudinal directions, respectively; fourth medium units are arranged in sequence at the outer periphery of the fifth medium units, respectively; second medium units are arranged in sequence at the outer periphery of the fourth medium units, respectively; third medium units are arranged in sequence at the outer periphery of the second medium units, respectively; first medium units are arranged between the fourth medium units and the second medium units; and sixth medium units are further arranged at the outermost layer.

[0007] The first medium unit, the second medium unit, the third medium unit, the fourth medium unit, the fifth medium unit and the sixth medium unit each have a five-layer structure; wherein the middle layer is a connecting layer, the upper and lower surfaces of the connecting layer are core medium layers, the outer surfaces of the upper and lower core medium layers are gradient impedance matching layers, and the outer surfaces of the core medium layers and the gradient impedance matching layers are air media; by adjusting the bottom width W1, the top width W2 and the height h2 of the core medium layer and the gradient impedance matching layer, six different transmission phase medium units with main polarization transmission phases of 0°, 60°, 120°, 180°, 240° and 300° are realized.

[0008] In the first medium unit, the connecting layer has a platform shape with a square cross section, the upper and lower surfaces of the connecting layer are columnar core medium layers with a square cross section, and the outer ends of the upper and lower core medium layers are table-shaped gradient impedance matching layers with a square cross section.

[0009] In the second medium unit, the connecting layer has a platform shape with a square cross section, the upper and lower surfaces of the connecting layer are columnar core medium layers with a square cross section, and the outer ends of the upper and lower core medium layers are prismatic table-shaped gradient impedance matching layers with a square cross section, the bottom width of the prismatic table is W1, the top width is W2, and the height is h2.

[0010] In the third medium unit, the connecting layer has a platform shape with a square cross section, the upper and lower surfaces of the connecting layer are columnar core medium layers with a square cross section, and the outer ends of the upper and lower core medium layers are conical table-shaped gradient impedance matching layers with a square cross section, the bottom width of the conical table is W1, the top width is W2, and the height is h2, and the height of the conical table of the third medium unit is greater than the height of the prismatic table of the second medium unit.

[0011] In the fourth dielectric unit, the connecting layer is a platform with a square cross-section. On the upper and lower sides of the connecting layer, there are columnar core dielectric layers with rectangular cross-sections. At the outer ends of the upper and lower core dielectric layers, there are trapezoidal stepped impedance matching layers with a bottom width of W1, a top width of W2, and a height of h2.

[0012] In the fifth dielectric unit, the connecting layer is a platform with a square cross-section. On the upper and lower sides of the connecting layer, there are columnar core dielectric layers with a rectangular cross-section. At the outer ends of the upper and lower core dielectric layers, there are frustum-shaped gradient impedance matching layers. The base width of the frustum is W1, the top width is W2, and the height is h2. The height of the frustum of the fifth dielectric unit is greater than the height of the trapezoidal frustum of the fourth dielectric unit.

[0013] In the sixth dielectric unit, the connecting layer is a platform with a square cross-section. On the upper and lower sides of the connecting layer (72), there are columnar core dielectric layers with a rectangular cross-section. At the outer ends of the upper and lower core dielectric layers, there are platform-shaped gradient impedance matching layers with a rectangular cross-section.

[0014] The gradient impedance matching layer, the connecting layer, and the core dielectric layer are all made of polylactic acid material and are formed using fused deposition modeling (FDM) 3D printing technology.

[0015] Beneficial Effects: This invention proposes a broadband circularly polarized dielectric transmission array with high aperture efficiency. By designing units with low insertion loss and gradient impedance matching structures, the bandwidth and gain of the circularly polarized dielectric transmission array are greatly expanded. Furthermore, by modifying the geometry of the dielectric units, polarization conversion and phase modulation of the circularly polarized transmitted wave can be achieved. Compared with circularly polarized transmission arrays manufactured using PCB technology, this method is more cost-effective and offers greater bandwidth advantages. Compared with 3D-printed transmission arrays, this invention uses only an integrated dual-functional layer to achieve phase modulation and polarization conversion, and achieves higher aperture efficiency and a wider axial ratio bandwidth. Testing of a circular aperture transmission array antenna sample composed of 384 units shows a 3dB gain bandwidth of 29.8%, a 3dB axial ratio bandwidth of 41.9%, and an aperture efficiency of 65.7%. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0017] Figure 1 This is a diagram showing the arrangement of the six media units in a specific embodiment of this discovery;

[0018] Figure 2 This is a schematic diagram of the structure of six media units in a specific embodiment of the present invention;

[0019] Figure 3 This is a graph showing the variation of the amplitude of the main polarization and cross-polarization transmission coefficients of the unit in this invention with frequency under two orthogonally polarized incident waves;

[0020] Figure 4 This is a graph showing the phase variation of the transmission coefficient of a right-hand circularly polarized wave under incident linearly polarized wave in this invention, as a function of frequency.

[0021] Figure 5 The graphs show the simulated and measured array gain and aperture efficiency as a function of frequency in this invention.

[0022] Figure 6 The simulated and measured array axial bandwidth in this invention;

[0023] Figure 7 This is a simulation and actual measurement pattern of the transmission array in this invention.

[0024] The diagram includes: a gradient impedance matching layer 71, a connection layer 72, a core dielectric layer 73, an air dielectric 74, a total height h1 for the dielectric unit, a bottom width W1, a top width W2, and a height h2; a first dielectric unit 1, a second dielectric unit 2, a third dielectric unit 3, a fourth dielectric unit 4, a fifth dielectric unit 5, and a sixth dielectric unit 6. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The present invention discloses a broadband circularly polarized dielectric transmission array with high aperture efficiency, comprising: a core dielectric layer, a graded impedance matching layer, and a connecting layer. By adjusting the structure of the core dielectric layer and the graded impedance matching layer, dielectric units with broadband and polarization conversion characteristics are obtained. Based on this, six dielectric units with different transmission phases are obtained by adjusting the geometry. 384 of the above dielectric units constitute a circular aperture transmission array.

[0027] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0028] As attached Figure 1As shown, the transmission array antenna consists of 384 dielectric element structures with six different transmission phases, forming a circular aperture transmission array. The six dielectric element structures with different transmission phases are: first dielectric element 1, second dielectric element 2, third dielectric element 3, fourth dielectric element 4, fifth dielectric element 5, and sixth dielectric element 6, with corresponding main polarization transmission phases of 0°, 60°, 120°, 180°, 240°, and 300°, respectively. The six dielectric element structures with different transmission phases are six polarization conversion phase shifting units, which are periodically distributed on the circular aperture of the planar dielectric transmission array to form the phase distribution of the focused beam pointing to the target, so that the phase difference between two orthogonal linearly polarized waves after incident is 90°, realizing the conversion of linearly polarized waves into circularly polarized waves. The 384 dielectric units with different transmission phases are arranged on a circular aperture transmission array as follows: at the center, there are two rows of sixth dielectric units 6 arranged horizontally in a cross shape and two rows of sixth dielectric units 6 arranged vertically; on the outer periphery of the horizontally and vertically arranged sixth dielectric units 6, there are fifth dielectric units 5 arranged in sequence; on the outer periphery of the fifth dielectric units 5, there are fourth dielectric units 4 arranged in sequence; on the outer periphery of the fourth dielectric units 4, there are second dielectric units 2 arranged in sequence; on the outer periphery of the second dielectric units 2, there are third dielectric units 3 arranged in sequence; a first dielectric unit 1 is also arranged between the fourth dielectric unit 4 and the second dielectric unit 2; in addition, there are sixth dielectric units 6 on the outermost layer.

[0029] The core dielectric layer is composed of cuboids of polylactic acid (PLA) material with air-filled sides. The two end-loaded gradient impedance matching layers are both composed of solid PLA cuboids. By adjusting the height and thickness of the core dielectric layer and the gradient impedance matching layers—that is, changing the total height h1, bottom width W1, top width W2, and height h2 of the dielectric unit—six dielectric units with primary polarization transmission phases of 0°, 60°, 120°, 180°, 240°, and 300° can be achieved. Specific parameters are shown in Table 1 below.

[0030] Table 1 Variation parameters of six media units

[0031]

[0032] The six different dielectric units with varying transmission phases can maintain a phase difference of approximately 90° between the transmission phases of two incident orthogonal linearly polarized waves over a wide range, thus achieving the function of converting linearly polarized waves into circularly polarized waves. The transmission phase of the unit's main polarized wave can be adjusted by modifying the height and thickness of the core dielectric layer and the gradient impedance matching layer.

[0033] The required phase compensation for each unit can be obtained through broadband phase compensation calculation. The phase to be compensated is quantized onto six specified transmission phase values, and the circularly polarized phase shift units are periodically arranged in a circular pattern to form a target-oriented focused beam.

[0034] As attached Figure 2 As shown: This embodiment provides six dielectric units with different transmission phases, including a core dielectric layer 73, a graded impedance matching layer 71, and a connecting layer 72. The six different dielectric units include dielectric units with transmission phases of 0°, 60°, 120°, 180°, 240°, and 300°, respectively.

[0035] Specifically, the first dielectric unit 1, the second dielectric unit 2, the third dielectric unit 3, the fourth dielectric unit 4, the fifth dielectric unit 5, and the sixth dielectric unit 6 each have a five-layer structure. The middle layer is a connecting layer 72, and the upper and lower sides of the connecting layer 72 are core dielectric layers 73. Outside the upper and lower core dielectric layers 73 is a gradient impedance matching layer 1, and outside the core dielectric layers 73 and the gradient impedance matching layer 71 is an air dielectric 74. By adjusting the bottom width of the core dielectric layer 73 and the gradient impedance matching layer 71 to W1, the top width to W2, and the height to h2, six different transmission phases of 0°, 60°, 120°, 180°, 240°, and 300° can be achieved for the dielectric units.

[0036] In the first dielectric unit 1, the connecting layer 72 is a platform with a square cross-section. A columnar core dielectric layer 73 with a square cross-section is provided on the upper and lower surfaces of the connecting layer 72. A frustum-shaped tapered impedance matching layer 71 with a square cross-section is provided at the outer ends of the upper and lower core dielectric layers 73. In the second dielectric unit 2, the connecting layer 72 is also a platform with a square cross-section. A columnar core dielectric layer 73 with a square cross-section is provided on the upper and lower surfaces of the connecting layer 72. A frustum-shaped tapered impedance matching layer 71 is provided at the outer ends of the upper and lower core dielectric layers 73. The frustum has a base width of W1, a top width of W2, and a height of h2. In the third dielectric unit 3, the connecting layer 72 is a platform with a square cross-section. A columnar core dielectric layer 73 with a square cross-section is provided on the upper and lower surfaces of the connecting layer 72. A frustum-shaped gradient impedance matching layer 71 is provided at the outer ends of the upper and lower core dielectric layers 73. The base width of the frustum is W1, the top width is W2, and the height is h2. The height of the frustum in the third dielectric unit 3 is greater than the height of the truncated pyramid in the second dielectric unit 2. In the fourth dielectric unit 4, the connecting layer 72 is a platform with a square cross-section. A columnar core dielectric layer 73 with a rectangular cross-section is provided on the upper and lower surfaces of the connecting layer 72. A trapezoidal frustum-shaped gradient impedance matching layer 71 is provided at the outer ends of the upper and lower core dielectric layers 73. The base width of the trapezoidal frustum is W1, the top width is W2, and the height is h2. In the fifth dielectric unit 5, the connecting layer 72 is a platform with a square cross-section. Rectangular columnar core dielectric layers 73 are provided on the upper and lower surfaces of the connecting layer 72. A frustum-shaped gradient impedance matching layer 71 is provided at the outer ends of the upper and lower core dielectric layers 73. The base width of the frustum is W1, the top width is W2, and the height is h2. The height of the frustum in the fifth dielectric unit 3 is greater than the height of the trapezoidal frustum in the fourth dielectric unit 4. In the sixth dielectric unit 6, the connecting layer 72 is a platform with a square cross-section. Rectangular columnar core dielectric layers 73 are provided on the upper and lower surfaces of the connecting layer 72. A frustum-shaped gradient impedance matching layer 71 is provided at the outer ends of the upper and lower core dielectric layers 73.

[0037] The gradient impedance matching layer 71, the connecting layer 72, and the core dielectric layer 73 are all made of polylactic acid material and are formed using fused deposition modeling 3D printing technology.

[0038] As attached Figure 3 As shown, the amplitude of the main polarization transmitted wave of the unit under the incidence of two orthogonal linearly polarized waves is greater than -0.7dB, and the amplitude of the cross-polarized transmitted wave is less than -15dB.

[0039] As attached Figure 4As shown, the transmission coefficient of the unit cell under incident linearly polarized wave is shown. The transmission phase curves of the six medium units are parallel to each other, and the transmission phase compensation can be quantized to six specified transmission phase values.

[0040] As attached Figure 5 As shown, the simulated and measured gain and aperture efficiency of the transmission array are presented. The array achieves an aperture efficiency of 65.7% and a peak gain of 26.2 dBic.

[0041] As attached Figure 6 As shown, the simulated and measured axial ratios of the transmission array are presented, and it can be seen that the array achieves a 3dB axial ratio bandwidth of 41.9%.

[0042] As attached Figure 7 As shown, the simulated and measured radiation patterns of the transmission array are presented. The simulated and measured radiation patterns are in excellent agreement, and the positions of the main lobe and side lobes can be predicted well. The intermediate frequency cross-polarization level is greater than 15 dB, and the side lobe level is less than -25 dB.

Claims

1. A broadband circularly polarized dielectric metasurface array antenna with high aperture efficiency, characterized in that: The transmission array antenna is composed of 384 medium unit structures with six different transmission phases, which form a circular aperture transmission array; The six different transmission phase medium units are respectively: first medium unit (1), second medium unit (2), third medium unit (3), fourth medium unit (4), fifth medium unit (5), and sixth medium unit (6), and the corresponding main polarization transmission phases are 0°, 60°, 120°, 180°, 240° and 300° respectively; the six different transmission phase medium units are six polarization conversion phase shift units, which are periodically distributed on the circular aperture of the planar medium transmission array to form the phase distribution of the target directional focusing beam, so that the phase difference of the two orthogonal linearly polarized waves is 90° after incidence, realizing the conversion from linearly polarized wave to circularly polarized wave.

2. The wideband circularly polarized dielectric transmitarray antenna with high aperture efficiency according to claim 1, wherein, The 384 different transmission phase medium unit structures are arranged on the circular aperture transmission array as follows: the central position is two rows of sixth medium units (6) arranged transversely and two rows of sixth medium units (6) arranged longitudinally; the outer periphery of the transversely and longitudinally arranged sixth medium units (6) is respectively provided with fifth medium units (5) arranged in sequence, the outer periphery of the fifth medium units (5) is respectively provided with fourth medium units (4) arranged in sequence, the outer periphery of the fourth medium units (4) is respectively provided with second medium units (2) arranged in sequence, the outer periphery of the second medium units (2) is respectively provided with third medium units (3) arranged in sequence, and the first medium units (1) are further arranged between the fourth medium units (4) and the second medium units (2); in addition, the outermost layer is provided with sixth medium units (6).

3. The wideband circularly polarized dielectric array antenna with high aperture efficiency according to claim 1 or 2, characterized in that, The first medium unit (1), the second medium unit (2), the third medium unit (3), the fourth medium unit (4), the fifth medium unit (5) and the sixth medium unit (6) are respectively composed of five layers of structures; wherein the middle layer is a connecting layer (72), the upper and lower surfaces of the connecting layer (72) are respectively core medium layers (73), the outer surfaces of the upper and lower core medium layers (73) are gradient impedance matching layers (71), and the outer surfaces of the core medium layers (73) and the gradient impedance matching layers (71) are air media (74); by adjusting the bottom width W1, the top width W2 and the height h2 of the core medium layer (73) and the gradient impedance matching layer (71), the six different transmission phase medium units with main polarization transmission phases of 0°, 60°, 120°, 180°, 240° and 300° are realized.

4. The wideband circularly polarized dielectric array antenna with high aperture efficiency according to claim 3, characterized in that, In the first medium unit (1), the connecting layer (72) is in the shape of a platform with a square cross section, the upper and lower surfaces of the connecting layer (72) are respectively provided with columnar core medium layers (73) with a square cross section, and the outer ends of the upper and lower core medium layers (73) are respectively provided with platform-shaped gradient impedance matching layers (71) with a square cross section.

5. The wideband circularly polarized dielectric array antenna with high aperture efficiency according to claim 3, characterized in that, The shape of the connecting layer (72) in the second medium unit (2) is a platform with a square cross section, and a columnar core medium layer (73) with a square cross section is arranged on the upper and lower surfaces of the connecting layer (72), and a prismatic frustum-shaped gradually changing impedance matching layer (71) is arranged at the outer end of the upper and lower core medium layers (73).

6. The wideband circularly polarized dielectric array antenna with high aperture efficiency according to claim 5, wherein, The shape of the connecting layer (72) in the third medium unit (3) is a platform with a square cross section, and a columnar core medium layer (73) with a square cross section is arranged on the upper and lower surfaces of the connecting layer (72), and a conical frustum-shaped gradually changing impedance matching layer (71) is arranged at the outer end of the upper and lower core medium layers (73), and the height of the conical frustum of the third medium unit (3) is greater than the height of the prismatic frustum of the second medium unit (2).

7. The wideband circularly polarized dielectric array antenna with high aperture efficiency according to claim 3, wherein, The shape of the connecting layer (72) in the fourth medium unit (4) is a platform with a square cross section, and a columnar core medium layer (73) with a rectangular cross section is arranged on the upper and lower surfaces of the connecting layer (72), and a trapezoidal frustum-shaped gradually changing impedance matching layer (71) is arranged at the outer end of the upper and lower core medium layers (73).

8. The wideband circularly polarized dielectric array antenna with high aperture efficiency according to claim 7, wherein, The shape of the connecting layer (72) in the fifth medium unit (5) is a platform with a square cross section, and a columnar core medium layer (73) with a rectangular cross section is arranged on the upper and lower surfaces of the connecting layer (72), and a conical frustum-shaped gradually changing impedance matching layer (71) is arranged at the outer end of the upper and lower core medium layers (73), and the height of the conical frustum of the fifth medium unit (5) is greater than the height of the trapezoidal frustum of the fourth medium unit (4).

9. The wideband circularly polarized dielectric array antenna with high aperture efficiency according to claim 3, wherein, The shape of the connecting layer (72) in the sixth medium unit (6) is a platform with a square cross section, and a columnar core medium layer (73) with a rectangular cross section is arranged on the upper and lower surfaces of the connecting layer (72), and a trapezoidal frustum-shaped gradually changing impedance matching layer (71) with a rectangular cross section is arranged at the outer end of the upper and lower core medium layers (73).

10. The wideband circularly polarized dielectric array antenna with high aperture efficiency according to claim 3, wherein, The gradually changing impedance matching layer (71), the connecting layer (72), and the core medium layer (73) are all composed of polylactic acid material and are processed by 3D printing technology of fused deposition modeling.

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