Ultra-wideband low-profile dual-polarized curved phased array antenna

Abstract

The application discloses an ultra-wideband low-profile dual-polarized curved surface phased array antenna, and belongs to the technical field of antenna engineering and the field of wireless communication. The phased array antenna comprises a plurality of elevation plane subarrays arranged along an axial direction; the elevation plane subarray is composed of a plurality of curved surface antenna units uniformly distributed along a circumferential direction, and the whole has a fan shape; the curved surface antenna unit comprises a curved surface dielectric block, a metasurface matching layer and a radiator layer conformally arranged on upper and lower surfaces of the curved surface dielectric block, a vertical feed balun, a wave-absorbing resistance layer and a metal floor layer. The antenna uses a flexible dielectric plate as a carrier of a radiation dipole, cooperates with a PCB metal floor, realizes that a horizontal polarization and a vertical polarization of two linear polarization directions have an antenna normal active standing wave ratio less than 3.0 within ten frequency bands, and realizes scanning within a range of ±60° in an azimuth plane.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of antenna engineering and wireless communication, and particularly relates to a super-wideband low-profile dual-polarized curved phased array antenna. BACKGROUND

[0002] With the rapid development of wireless communication technology, phased array antennas are widely used in radar, communication, sensing and other fields due to their fast beam scanning speed, flexible pattern shaping, strong anti-interference ability and high tracking accuracy. The new generation of radar systems is evolving towards a multi-functional integrated radio frequency system. As a radio frequency front-end, the phased array antenna plays a crucial role and needs to have the characteristics of super-wideband and low profile, and also needs to have the ability to conform to the platform carrier. How to overcome the mutual restriction of antenna bandwidth and profile height, how to keep the influence of curved conformal design on the performance of the antenna within a controllable range and other problems are difficult problems that need to be solved in current research. The present application is proposed to solve the comprehensive challenges of super-wideband, low profile, dual polarization, wide-angle scanning and curved technology.

[0003] A literature published in IEEE in 2016 "D.K. Papantonis and J.L. Volakis, "Dual-Polarized Tightly Coupled Array With Substrate Loading," in IEEE Antennas and Wireless Propagation Letters, vol. 15, pp. 325-328, 2016" proposes a dual-polarized tightly coupled dipole array (TCDA) that provides a bandwidth of 13.1:1. The array contains a resistive sheet in the substrate to suppress resonance within the operating band, and uses a dielectric layer as a guide structure to maintain high efficiency. An 8x8 array is verified to show that a 13.5:1 bandwidth with a standing wave ratio less than 3.1 is achieved within 0.29GHz-3.9GHz, ±45° scanning, and cross-polarization less than -20dB. However, this model cannot completely cover the super-wideband application frequency band of 0.2-2GHz (10:1 impedance bandwidth ratio), and the structure is a planar structure with a small scanning angle.

[0004] A Chinese invention patent with patent number CN112467400A proposes a super-wideband dual-polarized phased array antenna, but this antenna structure only achieves a bandwidth of 0.4-2.6GHz, and only achieves a 45° scan within 6.5 octaves, which cannot completely cover the super-wideband application frequency band of 0.2-2GHz (10:1 impedance bandwidth ratio).

[0005] In addition, phased array antennas need to flexibly cope with various complex physical environments and are loaded on complex platform carriers; a low-profile dual-polarized strongly coupled ultra-wideband full-wing conformal dipole phased array antenna is proposed in Chinese invention patent CN114566798A, the antenna structure realizes conformal with a large curvature surface, and can be applied to an airborne platform, but the model has a very high requirement for processing precision, and the frequency range only covers five octaves of 1-5GHz, still cannot meet the application frequency band of ultra-wideband, and the scanning angle is ±45°.

[0006] In the document "B. Wang, S. Yang, Z. Zhang, Y. Chen, S. Qu and J. Hu, "A Ferrite-Loaded Ultralow Profile Ultrawideband Tightly Coupled Dipole Array," in IEEE Transactions on Antennas and Propagation, vol. 70, no. 3, pp. 1965-1975, March 2022", a ferrite-loaded ultralow profile strongly coupled ultra-wideband dipole phased array is proposed, which realizes dual-polarized characteristics and ±60° scanning in E-plane and H-plane within a ten-octave operating bandwidth (0.2-2GHz). However, the antenna is still a planar structure, which is not suitable for curved surface conformal.

[0007] The existing scheme design can realize a ten-octave bandwidth alone, or can realize a curved surface conformal phased array alone. However, it is impossible to simultaneously realize the design of a curved surface conformal phased array antenna in a ten-octave ultra-wideband application frequency band, so the design of a curved surface conformal phased array antenna in this frequency band is still blank, but there is also an actual application demand. SUMMARY

[0008] The present application proposes an ultra-wideband low-profile dual-polarized curved surface phased array antenna to overcome the deficiencies of the prior art. The antenna uses a thin dielectric plate as a carrier of the radiating dipole, cooperates with a PCB metal floor, and arranges 5x10 phased array units in a length of 626mm, a height of 105mm, and a depth of 210mm. The antenna realizes that the horizontal polarization and the vertical polarization in two linear polarization directions are less than 3.0 in a ten-octave antenna normal active standing wave ratio, and the azimuth plane realizes ±60° scanning.

[0009] To achieve the purpose, the technical scheme adopted by the present application is as follows:

[0010] An ultra-wideband low-profile dual-polarized curved surface phased array antenna comprises a plurality of elevation plane subarrays arranged uniformly along an axial direction;

[0011] The elevation subarray is composed of a plurality of curved surface antenna units uniformly distributed along the circumference and has a whole fan shape.

[0012] The curved surface antenna unit comprises a metasurface matching layer, a curved surface dielectric block, a radiator layer, a vertical feed balun, a wave-absorbing resistance layer and a metal floor layer. The metasurface matching layer is composed of an upper dielectric substrate and a periodic metal patch on the upper surface thereof. The curved surface dielectric block is an arc-shaped dielectric block with the same curvature as the carrier. The upper and lower dielectric substrates are respectively located on the upper and lower surfaces of the curved surface dielectric block and conform to the curved surface dielectric block. The wave-absorbing resistance layer is placed between the radiator layer and the metal floor layer. The metal floor layer comprises a bottom dielectric substrate and a metal layer on the upper surface thereof. The vertical feed balun is a balanced feed balun for feeding the dual-polarized radiators.

[0013] Preferably, the dual-polarized radiators comprise horizontal polarization radiators arranged on the upper surface of the lower dielectric substrate and vertical polarization radiators arranged on the lower surface. The horizontal polarization radiators and the vertical polarization radiators have the same structure and are arranged orthogonally.

[0014] Preferably, the lower dielectric substrate is equally divided into four square regions, and the projection intersection points of the radiators of the two polarization directions are located at the center of one of the square regions.

[0015] Preferably, the horizontal polarization radiators and the vertical polarization radiators both adopt bowtie parallel dipoles. Each polarization radiator in one curved surface antenna unit comprises a complete dipole and two dipole arms. In the non-overlapping area of the projections of the radiators of the two polarization directions, the adjacent dipoles are coupled by metal patches.

[0016] Preferably, the vertical feed balun is composed of two orthogonal strip-line Marchand feed baluns, and the intersection position is the same as the projection intersection points of the radiators of the two polarization directions.

[0017] Preferably, the corresponding vertical area without radiators is square excavated.

[0018] Preferably, the upper layer medium substrate, the lower layer medium substrate and the bottom layer medium substrate are all flexible medium substrates.

[0019] Preferably, the wave-absorbing resistance layer is composed of an ITO resistance film.

[0020] Since the impedance variation rate of the low-frequency band antenna in the ten times frequency ultra-wideband antenna array is large, the application adopts a single polarization double-radiator parallel double-feed to reduce the impedance of the overall radiator of the antenna, so as to reduce the impedance variation rate.

[0021] The radiators of the two polarization directions in the application are respectively printed on the upper and lower surfaces of the flexible medium substrate, in the projection overlapping area, the radiators of the two polarization directions are coupled to each other as the coupling patch, and in the projection non-overlapping area, a rectangular metal patch is arranged on the projection surface of the adjacent dipole radiator for coupling. At the same time, since the metal structure cannot be printed on the medium block, a medium substrate with the same dielectric constant is covered on the 3D printed medium block for printing periodic metal patches, and the two form a metamaterial wide-angle impedance matching layer, which increases the working bandwidth of the antenna. In addition, the metasurface is arranged only in the upper area corresponding to the radiator, for realizing the impedance transition between the antenna and the free space, and the area without the radiator is excavated to remove the curved medium block, the radiator layer and the metasurface matching layer, so as to improve the impedance utilization rate of the medium and better realize the transition between the antenna impedance and the free space impedance.

[0022] Considering that the electromagnetic shielding property of the tapered microstrip balun is not good, the application adopts a strip line Marchand balun structure, which effectively compresses the distance between the radiator and the ground, reduces the profile height of the antenna, and has the advantages of wide frequency band, which is helpful to increase the overall bandwidth of the array.

[0023] The metal floor of the array adopts flexible PCB material, compared with the pure metal floor, the flexible PCB is more suitable for the complex conformal of the array on the transfer platform.

[0024] In summary, the beneficial effects of the application are as follows:

[0025] 1. The application designs an ultra-wideband curved dual-polarized phased array antenna. The radiation units of the antenna are distributed on a semicircular curved surface, which realizes wider beam coverage. According to the simulation results, the antenna realizes a normal standing wave ratio less than 3.0 within a ten times frequency working bandwidth.

[0026] 2. The application designs a single-polarized double-leaked knot type dipole parallel structure, which effectively reduces the overall impedance of the dipole antenna, thereby reducing the low-frequency impedance variation rate.

[0027] 3. The application realizes the conformal of the antenna on the curved surface, which can be applied to the complex shape of the transfer platform. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a one-dimensional array element model of an ultra-wideband low-profile curved surface phased array provided by an embodiment of the application.

[0029] Figure 2 is a unit model of an ultra-wideband low-profile curved surface phased array provided by an embodiment of the application.

[0030] Figure 3 is a 5x10 ultra-wideband low-profile curved surface phased array array model provided by an embodiment of the application.

[0031] Figure 4 is a top view of a unit super surface matching layer and a wave-absorbing resistance layer of an ultra-wideband low-profile curved surface phased array provided by an embodiment of the application.

[0032] Figure 5 is a top view of a unit radiator layer of an ultra-wideband low-profile curved surface phased array provided by an embodiment of the application.

[0033] Figure 6 is a side view of a unit group array direction and conformal direction feed structure of an ultra-wideband low-profile curved surface phased array provided by an embodiment of the application.

[0034] Figure 7 is an active standing wave ratio of a center unit port of an ultra-wideband low-profile curved surface phased array when scanning 0°, 30°, and 60° along the group array direction.

[0035] BRIEF DESCRIPTION OF DRAWINGS 1. super surface matching layer, 11. upper layer dielectric substrate, 12. circular metal patch; 2. curved surface dielectric block; 3. radiator layer, 31. lower layer dielectric substrate, 32. horizontal polarization radiator, 33. vertical polarization radiator, 34. rectangular metal patch, 35. feed point; 4. vertical feed balun, 41. horizontal polarization feed balun substrate, 42. horizontal polarization feed balun feed line, 43. vertical polarization feed balun substrate, 44. vertical polarization feed balun feed line, 5. wave-absorbing resistance layer, 6. metal floor layer. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the application clearer, the application will be further described in detail below in combination with embodiments and drawings.

[0037] The embodiment provides an ultra-wideband low-profile curved surface phased array antenna adopting a 5x10 array, and the structure is as shown in Figure 3 which includes 10 pitch surface sub-arrays uniformly arranged along the axial direction.

[0038] The pitch surface sub-array structure is as shown in Figure 1As shown, it is composed of 5 curved surface antenna units uniformly distributed along the circumference, and the whole is in the shape of a sector.

[0039] As shown in the figure, the curved surface antenna unit includes a metasurface matching layer, a curved surface dielectric block, a radiator layer, a vertical feed balun, a wave-absorbing resistance layer, and a metal floor layer. Figure 2 As shown in the figure, the metasurface matching layer is composed of an upper layer dielectric substrate and a periodic square metal patch on the upper surface thereof.

[0040] Figure 2 As shown in the figure, the radiator layer is composed of a lower layer dielectric substrate, a horizontal polarization radiator arranged on the upper surface of the lower layer dielectric substrate, and a vertical polarization radiator arranged on the lower surface. Figure 4 As shown in the figure, the horizontal polarization radiator and the vertical polarization radiator are bow-tie type parallel dipoles with the same structure and orthogonal arrangement; a single polarization radiator in one curved surface antenna unit includes one complete dipole and two dipole arms, and a single dipole arm and a single dipole arm of an adjacent curved surface antenna unit form a complete dipole; the lower layer dielectric substrate is equally divided into four square regions, and the projection overlapping midpoint positions of the radiators of the two polarization directions are located at the center positions of one of the square regions of the lower layer dielectric substrate, so that in the projection overlapping region, the radiators of the two polarization directions are mutually enhanced coupling patches, and in the projection non-overlapping region, rectangular metal patches are used for coupling between adjacent dipoles.

[0041] Figure 2 The curved surface dielectric block is an arc-shaped dielectric block with the same curvature as the carrier; the upper layer dielectric substrate and the lower layer dielectric substrate are flexible dielectric substrates and conform to the upper and lower surfaces of the curved surface dielectric block, respectively. In order to better realize the impedance transition of the radiator and the free space, square blocks are excavated in the corresponding vertical regions where the radiators are not arranged, and the curved surface dielectric block and the metasurface matching layer and the radiator layer above and below it are removed. Figure 5 The wave-absorbing resistance layer is an ITO resistance film placed between the radiator layer and the metal floor layer.

[0042] The metal floor layer includes a bottom layer flexible dielectric substrate and a metal layer on the upper surface thereof, and the metal floor layer is placed at the lowermost layer of the curved surface antenna unit and conforms to the carrier.

[0043] The metal floor layer includes a bottom layer flexible dielectric substrate and a metal layer on the upper surface thereof, and the metal floor layer is placed at the lowermost layer of the curved surface antenna unit and conforms to the carrier.

[0044] The metal floor layer includes a bottom layer flexible dielectric substrate and a metal layer on the upper surface thereof, and the metal floor layer is placed at the lowermost layer of the curved surface antenna unit and conforms to the carrier.

[0045] ​​The vertical feed bar is composed of a horizontal polarization feed bar and a vertical polarization feed bar arranged orthogonally; the horizontal polarization feed bar and the vertical polarization feed bar are both Marchand balanced feed bars with a strip line, and feed the dual-polarized radiator. Specifically, the feed bar includes a feed bar substrate and a feed bar feed line arranged on the surface; the bottom end of the feed bar feed line is a signal input end, and the upper side is divided into two feed line branches and connected to the feed points of the dipole radiators to provide balanced feed for the dipole radiators. Meanwhile, the vertical feed bar serves as a support structure to fix the relative positions of the curved dielectric block, the wave-absorbing resistor layer and the metal floor layer.

[0046] Figure 7 The active standing wave ratios of the curved antenna unit of the embodiment at different scanning angles along the array direction are given. As can be seen from the figure, the active standing wave ratios of the two polarizations are both less than 3.0 at the normal, and the standing wave ratios of the two polarizations at typical frequency points are also both less than 3.0 when scanning, realizing the wide-angle scanning of the ultra-wideband antenna.

Claims

1. An ultra-wideband low-profile dual-polarization curved phased array antenna, characterized in that: It includes a plurality of pitch plane sub-arrays uniformly arranged along the axial direction; The elevation sub-array is composed of a number of curved antenna units evenly distributed along the circumference, and the overall shape is fan-shaped; The curved antenna unit includes a metasurface matching layer, a curved dielectric block, a radiator layer, a vertical feeding balun, an absorbing resistor layer, and a metal floor layer; the metasurface matching layer is composed of an upper dielectric substrate and periodic metal patches on its upper surface; the radiator layer is composed of a lower dielectric substrate and dual-polarized radiators on its upper and lower surfaces; the curved dielectric block is an arc-shaped dielectric block with the same curvature as that of the carrier; the upper dielectric substrate and the lower dielectric substrate are respectively located on the upper and lower surfaces of the curved dielectric block and conform to the same; the absorbing resistor layer is placed between the radiator layer and the metal floor layer; the metal floor layer includes a bottom dielectric substrate and a metal layer on its upper surface; the metal floor layer is placed at the bottom layer of the curved antenna unit and conforms to the carrier; the vertical feeding balun uses a balanced feeding balun to feed the dual-polarized radiator, and at the same time, the vertical feeding balun serves as a supporting structure to fix the relative positions of the curved dielectric block, the absorbing resistor layer, and the metal floor layer; The phased array antenna achieves an antenna normal active standing wave ratio of less than 3.0 in two linear polarization directions of horizontal polarization and vertical polarization within ten octaves, and achieves ±60° scanning in the azimuth plane.

2. The ultra-wideband low-profile dual-polarization curved phased array antenna according to claim 1, characterized in that: The dual-polarized radiator comprises a horizontally polarized radiator arranged on the upper surface of the lower dielectric substrate and a vertically polarized radiator arranged on the lower surface; the horizontally polarized radiator and the vertically polarized radiator have the same structure and are orthogonally arranged.

3. The ultra-wideband low-profile dual-polarization curved phased array antenna according to claim 2, characterized in that: The lower dielectric substrate is equally divided into four square areas, and the overlapping midpoint of the projections of the radiators in the two polarization directions is located at the center of one of the square areas of the lower dielectric substrate.

4. The ultra-wideband low-profile dual-polarization curved phased array antenna according to claim 3, characterized in that: The horizontally polarized radiator and the vertically polarized radiator both use bowtie-type parallel dipoles; a single polarized radiator in a curved antenna unit includes a complete dipole and two dipole arms, and the single dipole arm and the single dipole arm of the adjacent curved antenna unit form a complete dipole; in the non-overlapping area of ​​the radiator projections in the two polarization directions, adjacent dipoles are coupled using metal patches.

5. The ultra-wideband low-profile dual-polarization curved phased array antenna according to claim 4, characterized in that: The vertical feeding balun is composed of two stripline Marchand feeding baluns arranged orthogonally, and the intersection position is the same as the overlapping midpoint of the projections of the radiators in the two polarization directions.

6. The ultra-wideband low-profile dual-polarization curved phased array antenna according to claim 5, characterized in that: A square block is dug in the corresponding vertical area where no radiator is set, and the area inside the square block is a blank area where no curved surface medium block, radiator layer, or metasurface matching layer is set.

7. The ultra-wideband low-profile dual-polarization curved phased array antenna according to claim 6, characterized in that: The upper dielectric substrate, the lower dielectric substrate and the bottom dielectric substrate are all flexible dielectric substrates.

8. The ultra-wideband low-profile dual-polarization curved phased array antenna according to claim 7, characterized in that: The wave absorbing resistor layer is formed by an ITO resistor film.

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