Modularized low-profile high-isolation dual-polarization millimeter wave phased array antenna

Abstract

A modular low-profile high-isolation dual-polarization millimeter wave phased-array antenna is composed of a plurality of antenna units which extend in the X polarization direction and the Y polarization direction respectively to form a plane of any size, and an antenna array is formed. The antenna unit comprises an upper-layer metasurface structure, a middle-layer antenna dielectric substrate and prepreg, a CSMP coaxial joint and a lower-layer metal floor in sequence from top to bottom; a square patch is printed on the upper surface of the metasurface structure, four layers of antenna dielectric substrates are arranged, and three layers of prepregs are connected with the antenna dielectric substrates.

Description

Technical Field

[0001] The present invention belongs to the technical field of phased array antennas, and in particular relates to a millimeter wave low-profile high-isolation technology. Background Art

[0002] The rapid development of modern wireless communication technology is placing increasingly higher demands on system transmission speed, size, cost, and power consumption. Previous communication systems primarily focused on the sub-6GHz frequency range, where bandwidth limitations made further improvements difficult.

[0003] Millimeter waves, operating between 30 and 300 GHz, offer more abundant spectrum resources and are relatively easy to allocate. Millimeter waves possess vast spectrum resources, enabling higher communication rates and greater throughput. The evolution of communication and radar systems to the millimeter wave band is inevitable. Millimeter waves hold enormous potential for application, including in fifth-generation mobile communications.

[0004] The millimeter-wave band's wide bandwidth advantage and practical system application requirements place even stricter design requirements on millimeter-wave antennas, such as high gain, narrow beam, wide bandwidth, low profile, low cost, and strong applicability. Millimeter-wave antenna design must balance various performance indicators to enhance antenna practicality.

[0005] The current millimeter-wave phased array antenna design has certain problems: the cross-section is high; although the bandwidth design of some antennas is relatively wide, they use thicker dielectric substrates and more dielectric layers; the antenna units are small, the spacing between units is close, and the coupling is difficult to control; it is difficult to achieve modular integration; and it is not easy to maintain. Summary of the Invention

[0006] To solve the above problems, a modular low-profile, high-isolation dual-polarized millimeter-wave phased array antenna is adopted. It consists of several antenna units, which extend along the X-polarization direction and the Y-polarization direction respectively to form a plane of arbitrary size to form an antenna array.

[0007] From top to bottom, the antenna unit consists of the upper metasurface structure, the middle antenna dielectric substrate and prepreg, the CSMP coaxial connector, and the lower metal floor. The antenna dielectric substrate has four layers, and the prepreg has three layers, which are connected to the antenna dielectric substrate.

[0008] Square patches are printed on the upper surface of the metasurface structure to improve the isolation between the dual-polarization antenna units and reduce the cross-polarization value of the antenna units.

[0009] An asymmetric dipole radiating arm is printed on the upper surface of the second dielectric substrate. One arm of the long dipole antenna and one arm of the short dipole antenna form an asymmetric dipole antenna, which achieves impedance compensation within the entire frequency band and improves the impedance matching of the antenna within the entire operating frequency band.

[0010] The input impedance of an asymmetric dipole is related to the input impedance of two long and short dipoles by the formula Indicates that Z A represents the input impedance of the asymmetric dipole, Z 1s , Z 2s Represent the input impedance of the long and short dipoles respectively. Within the entire operating frequency band, the input impedance of the asymmetric dipole is equivalent to the average of the input impedances of the two long and short dipoles. The impedance of the asymmetric dipole changes more smoothly within the entire frequency band. By optimizing the size parameters of the asymmetric dipole arm, a more stable input impedance is obtained within the antenna operating frequency band, and the degree of freedom of optimization design is increased.

[0011] A circular coupling patch is printed on the lower surface of the third dielectric substrate to increase the capacitive coupling between units, improve the working bandwidth of the antenna, and reduce the cross-sectional height of the antenna. The coupling patch is electrically connected to the metal floor through metallized vias to form a ridge waveguide structure, eliminating the common-mode resonance of the antenna.

[0012] The planar phased array antenna lacks a feeding balun structure, making it difficult to expand the bandwidth. Although asymmetric dipoles are used to improve impedance matching, the operating bandwidth is difficult to expand through this structure.

[0013] One of the important factors limiting the bandwidth of planar phased array antennas is the reactance load of the ground plane. By loading a circular coupling patch, a parallel plate capacitor structure is formed between the patch and the dipole radiating arm, increasing capacitive coupling, offsetting the reactance load of the ground plane, and broadening the low-frequency operating bandwidth of the antenna.

[0014] When directly feeding the antenna element with a 50Ω coaxial connector, the current in the feed post is not completely offset at certain frequencies, resulting in strong common-mode resonance. Based on the equivalent ridge waveguide theory, a coupling patch is added and combined with a metallized via structure to form an equivalent ridge waveguide structure, shifting the common-mode resonance point outside the operating frequency band.

[0015] The upper surface of the fourth dielectric substrate is printed with a bent microstrip transition line. Two CSMP connectors are installed in one antenna unit, and the signal of the CSMP coaxial connector is transferred to the radiation arm, realizing the modular distribution of the dual-polarized antenna unit and facilitating modular processing, assembly, disassembly and repair for subsequent maintenance.

[0016] The inner core of the CSMP coaxial connector conducts current to the feed dipole arm, which passes through other dipole arms and the ground column, generating a current of equal amplitude and opposite direction to the feed dipole arm, radiating energy into free space. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the antenna array diagram.

[0018] Figure 2 It is a schematic diagram of the metasurface structure.

[0019] Figure 3 It is a layered diagram of the antenna unit.

[0020] Figure 4 This is the simulation result of vertical standing wave ratio.

[0021] Figure 5 This is the simulation result of horizontal plane standing wave ratio.

[0022] Figure 6 This is a port isolation simulation diagram.

[0023] Figure 7 is the unit gain pattern.

[0024] Figure 8 is the vertical plane pattern Figure 9 is the horizontal plane pattern. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.

[0026] The antenna array size is 10×10, with 10 antenna elements along x Directionally arranged, 10 antenna units along y Direction arrangement, the unit spacing is 5.2mm, such as Figure 1 shown.

[0027] The upper surface of the metasurface structure is printed with square patches 119, e.g. Figure 2 As shown, the relative dielectric constants of the four-layer antenna dielectric substrate are all 2.94, and the relative dielectric constants of the three-layer prepreg are all 2.76. From top to bottom, the first dielectric substrate 101 is 0.127 mm thick, the first prepreg 105 is 0.12 mm thick, the second dielectric substrate 102 is 0.127 mm thick, the second prepreg 106 is 0.12 mm thick, the third dielectric substrate 103 is 0.127 mm thick, the third prepreg 105 is 0.254 mm thick, and the fourth dielectric substrate 104 is 0.127 mm thick. Figure 3 As shown, the total cross-sectional height of the antenna unit is 0.974 mm, which is only 0.12 times the high-frequency wavelength, and has good low-profile characteristics.

[0028] An asymmetric long dipole arm 109 and a short dipole arm 110 are printed on the upper surface of the second dielectric substrate 102 , each of which is composed of an isosceles trapezoid and an isosceles right triangle.

[0029] The trapezoidal upper base of the long dipole arm 109 is 0.6 mm, the lower base is 0.7 mm, the height is 2.3 mm, and the triangle base is 0.6 mm long; the trapezoidal upper base of the short dipole arm 110 is 0.6 mm, the lower base is 1.5 mm, the height is 1.2 mm, and the triangle base is 0.6 mm long.

[0030] A circular coupling patch 111 with a diameter of 2.8 mm is printed on the lower surface of the third dielectric substrate 103 and is connected to the metal floor 108 through a metallized via 113 .

[0031] Microstrip transition lines 115 and 117 are printed on the upper surface of the fourth dielectric substrate 104 . The inner cores 114 and 116 of the CSMP coaxial connector conduct the current to the short dipole arm 109 , and the shielding hole 118 provides shielding.

[0032] The short dipole arm 110 is connected to the metal base plate 108 through a metalized via 112 , and forms a current with equal amplitude and opposite direction to that of the dipole arm 109 through a grounding column 113 .

[0033] The simulation results of the vertical plane active voltage standing wave ratio changing with frequency are shown in the following figure: Figure 4 As shown in the figure, the active voltage standing wave ratio is less than 2 in the entire 32~36GHz frequency range.

[0034] The simulation results of the horizontal plane active voltage standing wave ratio changing with frequency are as follows Figure 5 As shown in the figure, in the entire 32~36GHz frequency range, the active voltage standing wave ratio is less than 2.5.

[0035] The isolation simulation results of the dual-polarization port are as follows: Figure 6 As shown in the figure, the polarization port isolation is less than -32dB in the entire 32~36GHz frequency range.

[0036] The unit gain pattern of the antenna unit at 36GHz is as follows Figure 7 As shown, the cross-polarization performance is good and the waveform is normal.

[0037] The vertical radiation pattern of the 10×10 antenna array at 6GHz frequency at 0°, 15°, and 30° scanning angles is as follows: Figure 8 As shown, the scanning beam is stable and the pointing is accurate.

[0038] The horizontal plane radiation pattern of the 10×10 antenna array at 6GHz frequency at 0°, 15°, and 30° scanning angles is as follows: Figure 9As shown, the scanning beam is stable and the pointing is accurate.

[0039] The above are embodiments of the present invention and do not limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention are included in the protection scope of the present invention.

Claims

1. A modular low-profile, high-isolation dual-polarized millimeter-wave phased array antenna, characterized in that: include: It is composed of several antenna units, which extend along the X-polarization direction and the Y-polarization direction respectively, forming a plane of any size to form an antenna array; From top to bottom, the antenna unit consists of the upper metasurface structure, the middle antenna dielectric substrate and prepreg, the CSMP coaxial connector, and the lower metal floor. The upper surface of the metasurface structure is printed with square patches, the antenna dielectric substrate has four layers, and the prepreg has three layers, which are connected to the antenna dielectric substrate.

2. The modular low-profile, high-isolation dual-polarized millimeter-wave phased array antenna according to claim 1, characterized in that: An asymmetric dipole radiating arm is printed on the upper surface of the second dielectric substrate. One arm of the long dipole antenna and one arm of the short dipole antenna form an asymmetric dipole antenna.

3. The modular low-profile, high-isolation dual-polarized millimeter-wave phased array antenna according to claim 1, characterized in that: A circular coupling patch is printed on the lower surface of the third dielectric substrate and is electrically connected to the metal floor through metallized vias to form a ridge waveguide structure.

4. The modular low-profile, high-isolation dual-polarized millimeter-wave phased array antenna according to claim 1, characterized in that: A bent microstrip transition line is printed on the upper surface of the fourth dielectric substrate. Two CSMP connectors are installed in one antenna unit, and the signal of the CSMP coaxial connector is transferred to the radiation arm.

5. The modular low-profile, high-isolation dual-polarized millimeter-wave phased array antenna according to claim 2, characterized in that: The relationship between the input impedance of the asymmetric dipole and the input impedance of the two long and short dipoles is expressed by the formula Indicates that Z A represents the input impedance of the asymmetric dipole, Z 1s , Z 2s Represent the input impedance of the long and short dipoles respectively. Within the entire operating frequency band, the input impedance of the asymmetric dipole is equivalent to the average value of the input impedance of the two long and short dipoles.

6. The modular low-profile, high-isolation dual-polarized millimeter-wave phased array antenna according to claim 4, characterized in that: The inner core of the CSMP coaxial connector conducts current to the feed dipole arm, and then passes through other dipole arms and the grounding column to generate a current with the same amplitude and opposite direction as the feed dipole arm, radiating energy into free space.

7. The modular low-profile, high-isolation dual-polarized millimeter-wave phased array antenna according to claim 1, characterized in that: The relative dielectric constants of the four layers of antenna dielectric substrates are all 2.94, and the relative dielectric constants of the three layers of prepregs are all 2.

76. From top to bottom, the first layer of dielectric substrate 101 is 0.127 mm thick, the first layer of prepreg 105 is 0.12 mm thick, the second layer of dielectric substrate 102 is 0.127 mm thick, the second layer of prepreg 106 is 0.12 mm thick, the third layer of dielectric substrate 103 is 0.127 mm thick, the third layer of prepreg 105 is 0.254 mm thick, and the fourth layer of dielectric substrate 104 is 0.127 mm thick.

8. The modular low-profile, high-isolation dual-polarized millimeter-wave phased array antenna according to claim 5, characterized in that: The long dipole arm and the short dipole arm are both composed of an isosceles trapezoid and an isosceles right triangle.

9. The modular low-profile, high-isolation dual-polarized millimeter-wave phased array antenna according to claim 8, characterized in that: The trapezoidal upper base of the long dipole arm is 0.6 mm, the lower base is 0.7 mm, the height is 2.3 mm, and the triangle base is 0.6 mm long; the trapezoidal upper base of the short dipole arm is 0.6 mm, the lower base is 1.5 mm, the height is 1.2 mm, and the triangle base is 0.6 mm long.

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