Ultra-wideband low-profile dual-polarization curved surface phased array antenna

Abstract

The invention discloses an ultra-wideband low-profile dual-polarization curved surface phased-array antenna, and belongs to the field of antenna engineering technology and wireless communication. The phased-array antenna comprises a plurality of pitching surface sub-arrays which are arranged along the axial direction; the pitching surface subarray is composed of a plurality of curved surface antenna units which are uniformly distributed along the circumference, and the whole pitching surface subarray is fan-shaped; the curved antenna unit comprises a curved dielectric block, a metasurface matching layer, a radiator layer, a vertical feed balun, a wave-absorbing resistance layer and a metal floor layer, wherein the metasurface matching layer and the radiator layer are conformally arranged on the upper surface and the lower surface of the curved dielectric block. According to the antenna, the flexible dielectric plate is used as a carrier of a radiation dipole and is matched with the PCB metal floor, so that the normal active standing-wave ratio of the antenna is smaller than 3.0 in ten octaves in two linear polarization directions of horizontal polarization and vertical polarization, and + / -60-degree scanning is realized in an azimuth plane.

Description

Technical Field

[0001] The invention belongs to the fields of antenna engineering technology and wireless communication, and specifically relates to an ultra-wideband low-profile dual-polarization curved phased array antenna. Background Art

[0002] With the rapid development of wireless communication technology, phased array antennas have been widely used in radar, communication, sensing and other fields due to their advantages such as 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 multifunctional integrated RF system. Phased array antennas play a vital role as the RF front end. They need to have the characteristics of ultra-wideband and low profile, and at the same time, they need to have the ability to conform to the platform carrier. How to overcome the mutual constraints between antenna bandwidth and profile height, how to keep the impact of curved conformal design on antenna performance within a controllable range, etc., are all difficult problems that need to be solved urgently in current research. The present invention is proposed in response to the challenges of the integration of ultra-wideband, low profile, dual polarization, large angle scanning, and curved technology.

[0003] A paper published in IEEE in 2016, "DKPapantonis and JLVolakis,"Dual-Polarized Tightly Coupled Array With Substrate Loading," in IEEE Antennas and Wireless Propagation Letters, vol. 15, pp. 325-328, 2016", proposed a dual-polarized tightly coupled dipole array (TCDA) that provides 13.1:1 bandwidth. The array contains a resistor sheet in the substrate to suppress resonance within the operating band, and uses a dielectric layer as a guiding structure to maintain high efficiency. Verification with an 8×8 array showed that a 13.5:1 bandwidth with a standing wave ratio of less than 3.1, ±45° scanning, and cross-polarization of less than -20dB was achieved within 0.29GHz-3.9GHz. However, this model cannot fully cover the ultra-wideband application 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 an ultra-wideband dual-polarization phased array antenna. However, this antenna structure only achieves a bandwidth of 0.4-2.6 GHz and only achieves 45° scanning within 6.5 octaves, which cannot fully cover the ultra-wideband application frequency band of 0.2-2 GHz (10:1 impedance bandwidth ratio).

[0005] In addition, phased array antennas need to flexibly respond to various complex physical environments and be loaded on complex platform carriers. The Chinese invention patent with patent number CN114566798A proposes a low-profile dual-polarization strongly coupled ultra-wideband full-wing conformal dipole phased array antenna. The antenna structure is conformal to the large curvature surface and can be applied to airborne platforms. However, the model has extremely high requirements on processing accuracy, and the frequency range only covers five octaves of 1-5GHz, which still cannot meet the application frequency band of ultra-wideband, and the scanning angle is also ±45°.

[0006] 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" proposes a ferrite-loaded ultralow profile strongly coupled ultrawideband dipole phased array, which achieves dual polarization characteristics and ±60° scanning of the E and H planes within a ten-fold working bandwidth (0.2-2 GHz). However, the antenna is still a planar structure, which is not suitable for curved surface conformality.

[0007] The existing design scheme can achieve a bandwidth of ten octaves alone, and can also achieve a curved conformal phased array alone. However, it is impossible to simultaneously achieve the design of a curved conformal phased array antenna for a ten-octave ultra-wideband application frequency band. Therefore, the design of a curved conformal phased array antenna in this frequency band is still blank, but at the same time there is a practical application demand. Summary of the invention

[0008] In view of the shortcomings of the prior art, the present invention proposes an ultra-wideband low-profile dual-polarization curved phased array antenna. The antenna uses a thin dielectric plate as a carrier of the radiating dipole, and with a PCB metal floor, 5×10 phased array units are arranged in a length of 626mm, a height of 105mm, and a depth of 210mm. The antenna achieves an active standing wave ratio of less than 3.0 in the normal direction of the antenna in the two linear polarization directions of horizontal polarization and vertical polarization within ten octaves, and achieves ±60° scanning in the azimuth plane.

[0009] In order to achieve this purpose, the technical solution adopted by the present invention is:

[0010] An ultra-wideband low-profile dual-polarization curved phased array antenna, comprising a plurality of elevation plane sub-arrays uniformly arranged along an axial direction;

[0011] The elevation plane subarray is composed of a number of curved antenna units evenly distributed along the circumference, and is fan-shaped as a whole;

[0012] The curved antenna unit comprises 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 a periodic metal patch on its upper surface; the radiator layer is composed of a lower dielectric substrate and a dual-polarized radiator on its upper and lower surfaces; the curved dielectric block is an arc-shaped dielectric block with the same curvature as that of a 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 comprises a bottom dielectric substrate and a metal layer on its upper surface, and the metal floor layer is placed at the bottom layer of the curved antenna unit and conforms to the carrier; the vertical feeding balun adopts 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.

[0013] Preferably, 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 placed.

[0014] Preferably, the lower dielectric substrate is equally divided into four square areas, and the overlapping midpoint of the projections of the radiators in two polarization directions is located at the center of one of the square areas of the lower dielectric substrate.

[0015] Preferably, the horizontally polarized radiator and the vertically polarized radiator both adopt 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 constitute a complete dipole; in the non-overlapping area of ​​the radiator projections in the two polarization directions, adjacent dipoles are coupled by means of metal patches.

[0016] Preferably, 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 position of the projections of the radiators in the two polarization directions.

[0017] Preferably, a square block is dug in the corresponding vertical area where no radiator is set, and the inside of the square block is a blank area where no curved dielectric block, radiator layer, or metasurface matching layer is set, that is, only the curved dielectric block and the metasurface matching layer are set in the area above the radiator.

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

[0019] Preferably, the wave absorbing resistor layer is made of ITO resistor film.

[0020] Since the impedance change rate of the low-frequency antenna in the ten-fold frequency ultra-wideband antenna array is relatively large, the present invention adopts a single polarized dual radiator in parallel with dual feeding to reduce the impedance of the entire antenna radiator, thereby achieving the effect of reducing the impedance change rate.

[0021] The radiators of the two polarization directions in the present invention are printed on the upper and lower surfaces of the flexible dielectric substrate respectively. In the overlapping projection area, the radiators of the two polarization directions are coupled patches that enhance coupling with each other, and in the non-overlapping projection area, rectangular metal patches are set on the projection surface of adjacent dipole radiators for coupling. At the same time, since the metal structure cannot be printed on the dielectric block, a layer of dielectric substrate with the same dielectric constant is covered on the 3D printed dielectric block for printing periodic metal patches. The two form a wide-angle impedance matching layer of the metamaterial, which increases the working bandwidth of the antenna. In addition, a metasurface is set only in the upper area corresponding to the radiator to realize the impedance transition between the antenna and the free space, and the area where the radiator is not set is dug to remove the curved dielectric block, the radiator layer, and the metasurface matching layer to improve the impedance utilization 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 gradient micro-line balun is poor, the present invention adopts a stripline Marchand balun structure, which effectively compresses the distance between the radiator and the ground, reduces the cross-sectional height of the antenna, and has the advantage of wide bandwidth, which helps to increase the overall bandwidth of the array.

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

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

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

[0026] 2. The present invention designs a single-polarized double-bow-tie dipole parallel structure, which effectively reduces the overall impedance of the dipole antenna, thereby reducing the low-frequency impedance change rate.

[0027] 3. The present invention realizes the conformality of the antenna on the curved surface and can be applied to transfer platforms with complex shapes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention provides a one-dimensional array element model of an ultra-wideband low-profile curved phased array.

[0029] Figure 2 It is an ultra-wideband low-profile curved phased array unit model provided by an embodiment of the present invention.

[0030] Figure 3 It is a 5×10 ultra-wideband low-profile curved phased array model provided by an embodiment of the present invention.

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

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

[0033] Figure 6 It is a side view of the feeding structure in the array direction and conformal direction of the ultra-wideband low-profile curved phased array unit provided by an embodiment of the present invention.

[0034] Figure 7 It is the active standing wave ratio when the central unit port of the ultra-wideband low-profile curved phased array provided by an embodiment of the present invention scans 0°, 30°, and 60° along the array direction.

[0035] Explanation of the reference numerals: 1. metasurface matching layer, 11. upper dielectric substrate, 12. circular metal patch; 2. curved dielectric block; 3. radiator layer, 31. lower dielectric substrate, 32. horizontally polarized radiator, 33. vertically polarized radiator, 34. rectangular metal patch, 35. feeding point; 4. vertically fed balun, 41. horizontally polarized fed balun substrate, 42. horizontally polarized fed balun feed line, 43. vertically polarized fed balun substrate, 44. vertically polarized fed balun feed line, 5. absorbing resistor layer, 6. metal floor layer. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the implementation modes and the accompanying drawings.

[0037] This embodiment provides an ultra-wideband low-profile curved phased array antenna using a 5×10 array, whose structure is as follows: Figure 3 As shown, it includes 10 elevation plane sub-arrays uniformly arranged along the axial direction.

[0038] The pitch plane sub-array structure is as follows: Figure 1As shown, it is composed of five curved antenna units evenly distributed along the circumference, and the overall shape is a fan.

[0039] like Figure 2 As shown, 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.

[0040] like Figure 2 , Figure 4 As shown, the metasurface matching layer is composed of an upper dielectric substrate and periodic square metal patches on its upper surface.

[0041] like Figure 2 , Figure 5 As shown, the radiator layer is composed of a lower dielectric substrate, 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 are bowtie-type parallel dipoles with the same structure and orthogonally placed; 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 constitute a complete dipole; the lower dielectric substrate is divided into four square areas, and the overlapping midpoint position of the projections of the radiators in the two polarization directions is located at the center position of one of the square areas of the lower dielectric substrate, therefore, in the overlapping area of ​​the projections, the radiators in the two polarization directions are coupling patches that enhance coupling with each other, and in the non-overlapping area of ​​the projections, adjacent dipoles are coupled by rectangular metal patches.

[0042] The curved dielectric block is an arc-shaped dielectric block with the same curvature as the carrier; the upper dielectric substrate and the lower dielectric substrate are flexible dielectric substrates, and are respectively located on the upper and lower surfaces of the curved dielectric block and conform to it. In order to better achieve the impedance transition between the radiator and the free space, a square block is dug in the corresponding vertical area where the radiator is not set, and the curved dielectric block and the metasurface matching layer and radiator layer above and below it are removed.

[0043] The wave absorbing resistor layer is an ITO resistor film, which is placed between the radiator layer and the metal floor layer.

[0044] The metal floor layer comprises a bottom flexible 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.

[0045] The vertical feeding balun is composed of a horizontal polarization feeding balun and a vertical polarization feeding balun orthogonally arranged; the horizontal polarization feeding balun and the vertical polarization feeding balun both adopt stripline Marchand balanced feeding balun to feed the dual polarization radiator. Specifically, the feeding balun includes a feeding balun substrate and a feeding balun feed line arranged on the surface; the bottom end of the feeding balun feed line is a signal input end, and the upper part is divided into two feeding line branches and connected to the feeding point of the dipole radiator to provide balanced feeding for the dipole radiator. 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.

[0046] Figure 7 The active standing wave ratio of the curved antenna unit of this embodiment at different scanning angles along the array direction is given. It can be seen from the figure that in the normal direction, the active standing wave ratio of both polarizations is less than 3.0, and when scanning, the standing wave ratio of the typical frequency points of the two polarizations is also less than 3.0, realizing the ultra-wideband wide-angle scanning of the 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 plane subarray is composed of a number of curved antenna units evenly distributed along the circumference, and is fan-shaped as a whole; The curved antenna unit comprises 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 a periodic metal patch on its upper surface; the radiator layer is composed of a lower dielectric substrate and a dual-polarized radiator on its upper and lower surfaces; the curved dielectric block is an arc-shaped dielectric block with the same curvature as that of a 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 comprises a bottom dielectric substrate and a metal layer on its upper surface, and the metal floor layer is placed at the bottom layer of the curved antenna unit and conforms to the carrier; the vertical feeding balun adopts 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.

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 placed.

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 adopt 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 constitute a complete dipole; in the non-overlapping area of ​​the radiator projections in the two polarization directions, adjacent dipoles are coupled by means of 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 position 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 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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