One-dimensional ultra-wideband low-profile wide-angle scanning tight coupling array

Abstract

The invention belongs to the technical field of microwave antennas, and particularly provides a one-dimensional ultra-wideband low-profile wide-angle scanning tight coupling array, so as to realize wide-angle scanning of the one-dimensional ultra-wideband low-profile wide-angle scanning tight coupling array and have the characteristic of higher mechanical stability. The broadband high-efficiency electromagnetic structure comprises a broadband matching structure (I), namely a symmetrical rectangular parasitic patch loaded on the broadband high-efficiency electromagnetic structure; the radiation structure (II) is a metal support arm of a front metal dipole and a metal support of a rear metal dipole gradient structure; and the feed structure (III) comprises a gradient microstrip feeder, a floor and a coaxial line. According to the broadband high-performance electromagnetic structure, the parasitic patches are loaded above the array elements, so that reverse current occurring in the scanning process of the broadband high-performance electromagnetic structure can be effectively suppressed, and the wide-angle scanning performance of the antenna is remarkably improved. In the modern military field, the design of the array antenna is required to meet the requirements of miniaturization and low profile so as to reduce the volume of the whole system and the invested cost. Meanwhile, the array antenna has wide-angle scanning capability and relatively small gain loss, so that beam coverage in a wide airspace is realized. The method can be used for electronic countermeasure systems and high-speed moving aircrafts.

Description

Technical Field

[0001] This invention belongs to the field of microwave antenna technology, specifically providing a one-dimensional ultra-wideband low-profile wide-angle scanning tightly coupled array. Background Technology

[0002] Antennas are core components of modern wireless information systems, primarily responsible for energy conversion between electromagnetic waves in free space and guided waves within transmission lines. In applications with lower requirements for beam directivity and gain, single-element antennas, with their simple structure, low power consumption, and omnidirectional coverage, can meet basic communication needs. However, in situations requiring high gain and high directivity, array antennas are more effective at achieving directional energy radiation and beam concentration.

[0003] To meet the demands of wide-area coverage, modern communication platforms require array antennas to possess capabilities such as dynamic beamforming and rapid scanning. Phased array antennas, by electronically controlling the phase distribution of radiating elements, can achieve rapid beam pointing and scanning without mechanical rotation, exhibiting excellent dynamic beam reconfiguration capabilities, thus becoming an important technological path in high-performance communication systems. Tightly coupled antennas, due to the strong mutual coupling between elements, exhibit significant wideband characteristics. By rationally utilizing the coupling mechanism, the operating bandwidth of the antenna can be effectively extended without introducing additional decoupling structures.

[0004] Since Wheeler proposed the concept of the "infinite current sheet" in 1965, this theory has provided an important basis for the design of tightly coupled arrays. Its core idea is to divide the space in front of the antenna into parallel waveguides or transmission channels, and to approximate the radiation behavior of an infinite current sheet using a coupled dipole array of finite size. Tightly coupled phased arrays enhance mutual coupling by reducing the element spacing, thereby achieving an integrated design of wide-angle scanning, ultra-wideband response, and low-profile characteristics. Summary of the Invention

[0005] The goal of this invention is to fill the gap in the field of broadband high-efficiency electromagnetic structure tightly coupled phased array antenna technology, and to invent a one-dimensional ultra-wideband low-profile wide-angle scanning tightly coupled array.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention mainly consists of a wide-angle scanning matching layer, a broadband high-efficiency electromagnetic structure, a feeding structure, and a metal ground plane. The broadband high-efficiency electromagnetic structure adopts a tightly coupled array design, achieving broadband characteristics through the strong coupling effect between units. The wide-angle scanning matching layer is disposed on the upper surface of the dielectric substrate, and the broadband high-efficiency electromagnetic structure is disposed on the lower surface of the dielectric substrate. The two are isolated from each other by the dielectric substrate and maintain a predetermined distance. The introduction of the wide-angle scanning matching layer effectively improves the impedance matching performance of the antenna during large-angle scanning, significantly increasing the antenna's scanning range.

[0008] The feeding structure employs a tapered microstrip line design, with the width of the microstrip line continuously varying along the transmission direction. This achieves a smooth impedance transition from the feeding port to the radiating element, effectively solving the challenge of broadband impedance matching. A metal ground plane is positioned below the tapered microstrip line, providing not only electromagnetic shielding and back-radiation suppression, but also, through a 100Ω absorbing resistor placed at a specific location, efficiently absorbing residual reflected waves. This further enhances the isolation between array elements and improves overall radiation performance.

[0009] The innovation of this invention lies in:

[0010] I. By replacing the dipoles in the traditional tightly coupled array with a broadband high-performance electromagnetic structure, a one-dimensional linear array was designed, which achieves a lower profile height and a larger bandwidth compared to the traditional tightly coupled linear array.

[0011] Second, the introduction of parasitic patches above the array elements suppresses the reverse current that appears at the center of the broadband high-performance electromagnetic structure during scanning, solving the problem of scanning blind spots in the band when the broadband high-performance electromagnetic structure is used as a driving unit for tightly coupled arrays, thereby improving the wide-angle scanning capability. Attached Figure Description

[0012] Figure 1 is an overall view of the unit structure of the one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array disclosed in an embodiment of the present invention;

[0013] Figure 2 This is a schematic diagram of the unit feeding structure and radiation structure of the one-dimensional ultra-wideband low-profile wide-angle scanning tightly coupled array disclosed in an embodiment of the present invention;

[0014] Figure 3 This is a front view of the cell feeding structure of a one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array disclosed in an embodiment of the present invention;

[0015] Figure 4 This is a back view of the cell feeding structure of a one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array disclosed in an embodiment of the present invention;

[0016] Figure 5 This is a top view of the unit radiation structure of the one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array disclosed in an embodiment of the present invention;

[0017] Figure 6 This is a bottom view of the unit radiation structure of the one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array disclosed in an embodiment of the present invention;

[0018] Figure 7 The active standing wave curves of the one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array disclosed in the embodiments of the present invention when scanning at different angles;

[0019] Figure 8 The radiation pattern of the one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array disclosed in the embodiment of the present invention when scanning at different angles at a frequency of 2.75 GHz is shown. Detailed Implementation

[0020] To make the objectives, technical solutions, and innovations of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and examples.

[0021] Figure 2 This is a schematic diagram of the unit feed structure and radiation structure of the present invention. The structure of the present invention includes, from top to bottom, a radiation structure and a feed structure. Among them, (1) is a wide-angle matching layer, which consists of two sets of symmetrical rectangular parasitic patches. The rectangular parasitic patches are composed of two rectangles, with the larger rectangle having a length L. 17= 14mm, width W 12= 12mm, shorter rectangle length L 18= 14mm, width W 11= 8mm. The distance W between the patch and the edge. 28 =3.7mm; (2) is a broadband high-efficiency electromagnetic structure, on which two opening structures are loaded. The loaded opening structure 2 is designed as two trapezoids. The long side w of trapezoid 1 24 =40mm, short side W 26 =2mm, height H4=10.5mm, the shorter side W of trapezoid 2 27 =1.3mm, long side W 25 =25.3mm, height H5=27mm, the size of the introduced capacitor can be controlled by adjusting the spacing between the two inverted trapezoids and the size of the inverted trapezoids. The short side L of the rectangular opening structure... 22 =2mm, the long side W of the coupling metal patch 23 =3mm, short side W 17 =1.5mm, other parameters of the broadband high-efficiency electromagnetic structure L 22 =2mm, W 25 =25.3mm, W 16 =1mm; (3) is a dielectric substrate connecting the wide-angle scanning matching layer and the broadband high-efficiency electromagnetic structure. The dielectric substrate 3 is cuboid, the relative permittivity of the dielectric substrate 3 is 3.48, the relative permeability is 1, the loss tangent is 0.004, and the long side L 16 =62mm, short side W 10 =30mm, height H1=3mm, dielectric substrate 3 fixes the feed structure by embedding; (7) is a dielectric substrate supporting the feed network, the thickness of the gradient structure dielectric substrate (7) is 0.762mm and the height H3=25mm; (6) microstrip matching circuit, with Figure 3Taking the front view as an example, the overall width of the metal floor is W5=2.6mm, L1=7mm, L2=5.5mm, L3=12.5mm, L4=7.93mm, L5=3.43mm, L6=6.6mm, W2=0.9mm, W3=2.6mm, and W4=1.4mm. The metal floor integrates absorbing resistors, which can effectively improve the isolation between array units. Impedance matching characteristics can be optimized by adjusting the gradient dimensions of the microstrip lines; the isolation performance can be further improved by adjusting the position and resistance value of the absorbing resistors. The microstrip matching circuit can be referenced in the back view, with the following parameters: first impedance matching line W9=1.6mm, L7=4mm; second impedance matching line L8=2.18mm, L9=6.65mm, W8=1.15mm, L... 10 =5mm, third impedance matching line L 11 =5.79mm, W7=0.63mm, L 12 =5.5mm, L 13 =6.58mm, fourth impedance matching line L 14 =2.8mm, L 15 =2.3mm, W6=0.34mm. The feed impedance increases sequentially from top to bottom, thus reducing the amount of reflected energy during transmission. (10) is the metal ground plane of the antenna, with a length of L. 15 =58mm, width is W1=30mm, the function of the metal ground plane (10) is to suppress back radiation and improve antenna gain. (9) is the coaxial connector of the antenna, used to feed energy into the antenna.

[0022] Figure 7 The active standing wave ratio (VSWR) curves of a one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array are shown for scanning at 0°, 30°, and 50° under infinite boundary conditions. This array achieves a 5.48 octave bandwidth (0.66GHz-3.62GHz) and a 50° scanning capability with an active VSWR less than 3.2, and the array's profile height is only 0.064 low-frequency wavelengths.

[0023] Figure 8 The diagram shows the radiation patterns of the array at 2.75 GHz when scanning at 0°, 30°, and 50° under infinite boundary conditions. It can be seen that the antenna can scan the radiation pattern within a range of ±50 degrees. When scanning to 30° and 50°, the maximum gain of the array's main beam points to 30° and 50° respectively, which can achieve wide-angle scanning while introducing only low gain loss.

[0024] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array, comprising a radiating structure and a feeding structure, characterized in that: The radiating portion includes: a wide-angle scanning matching layer (1) disposed on the top layer, wherein the introduction of parasitic patches on the top layer can solve the problem of scanning blind spots in the band and is used to extend the antenna scanning range; a broadband high-efficiency electromagnetic structure (2); a dielectric substrate (3) supporting the wide-angle scanning matching layer (1); a dielectric substrate (4) supporting the broadband high-efficiency electromagnetic structure (2); and a metal short-circuit post (5) for improving impedance matching. The power supply section includes: a microstrip matching circuit (6) for impedance transformation; a dielectric substrate (7) supporting the power supply network; a resistive element (8) for suppressing reflection, with absorbing resistors configured in key areas to efficiently absorb residual reflected waves, further improving the isolation between array units and improving overall radiation performance; a coaxial connector (9); and a metal ground plane (10) for suppressing back radiation.

2. The one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array according to claim 1, characterized in that: The broadband high-efficiency electromagnetic structure (2) is connected through a dielectric substrate (3). Two rectangular parasitic patches are loaded on the top of the broadband high-efficiency electromagnetic structure (2). The wide-angle scanning matching layer (1) is disposed on the upper surface of the dielectric substrate (3), and the broadband high-efficiency electromagnetic structure (2) is disposed on the lower surface of the dielectric substrate (3). The wide-angle scanning matching layer (1) and the broadband high-efficiency electromagnetic structure (2) are isolated from each other through the dielectric substrate (3) and maintain a predetermined distance, thereby significantly enhancing the radiation performance of the phased array in the wide-angle scanning state of the antenna.

3. The one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array according to claim 1, characterized in that: The microstrip matching circuit (6) adopts a serpentine trace structure with gradually changing linewidth, which can realize continuous impedance transformation and thus achieve broadband matching; the metal ground plane (10) is located below the microstrip line, which plays the role of electromagnetic shielding and suppressing back radiation, and helps to improve the antenna gain; the resistor element (8) is arranged in a specific area of ​​the metal ground plane to absorb reflected energy and improve port isolation; the coaxial connector (9) is connected to the microstrip matching circuit and the balun (6) to realize signal feeding.

4. The one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array according to claim 1, characterized in that: The antenna element has a lateral dimension of 62mm × 30mm and a cross-sectional height of 29mm.

5. The one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array according to claim 1 or 2, characterized in that: The dielectric substrate (3) connecting the broadband high-efficiency electromagnetic structure (2) and the wide-angle scanning matching layer (1) has a relative permittivity of 3.48, a relative permeability of 1, a loss tangent of 0.004, a lateral dimension of 62mm × 30mm, and a height of 3mm.

6. The one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array according to claim 1 or 2, characterized in that: The wide-angle scanning matching layer (1) is composed of two sets of symmetrical rectangular parasitic patches. The introduction of the wide-angle scanning matching layer (1) above the array element, namely two sets of symmetrical rectangular parasitic patches, can suppress the reverse current that appears in the center of the broadband high-performance electromagnetic structure during scanning. This solves the problem of scanning blind spots in the band when the broadband high-performance electromagnetic structure is used as a driving unit of the tightly coupled array, thereby improving the wide-angle scanning capability.

7. The one-dimensional ultrawideband low-profile wide-angle scanning tightly coupled array according to claim 1 or 3, characterized in that: The microstrip matching circuit (6) has a serpentine structure, with the widths of the microstrip lines from bottom to top being 1.6mm, 1.15mm, and 0.63mm, and the lengths of the microstrip lines from bottom to top being 4mm, 21.425mm, and 17.235mm, respectively; and the width of the metal on its back side is 2.6mm.

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