All-metal casting integrated tight-coupled array

Abstract

The present invention belongs to the technical field of microwave antennas, and specifically provides an all-metal casting integrated tightly coupled array to achieve the high power resistance and stronger mechanical stability of tightly coupled phased array antennas. The present invention includes: a radiation structure, namely a metal dipole, an open ring structure, a metal plate, and a first metal cavity; a feeding structure, namely a second metal cavity, an open slot, a floor, and a coaxial line; a wide-angle matching layer, namely a split ring and its cross-complementary structure, and a dielectric plate. The present invention realizes the feeding of the dipole by using a slot with a gradually changing width in the metal structure, and introduces capacitive coupling between adjacent dipoles by using a metal plate perpendicular to the dipole and a first metal cavity opened under the dipole, thereby expanding the low-frequency bandwidth of the antenna. The invention can be used in electronic countermeasure systems and high-speed aircraft.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave antennas, and specifically provides an all-metal casting integrated tightly coupled array. Background Art

[0002] In wireless communication and radar systems, in order to improve the information transmission rate, extend the communication distance and increase the airspace coverage, ultra-wideband angular scanning phased array technology is often used. The traditional design idea of ​​ultra-wideband phased array is to first design units with broadband performance, and then form an array of units. This array formation method will increase the coupling between units due to the increase in the number of antenna units, which will have a negative impact on the broadband performance of the antenna units. In order to suppress the mutual coupling effect between units, the unit spacing can be increased, but too large a unit spacing will cause grating lobes to appear in the radiation pattern and increase the array volume. Although special structures can be loaded between array elements to suppress mutual coupling, this will complicate the phased array structure.

[0003] In order to solve the above problems, the tightly coupled phased array antenna technology based on Wheeler's infinite current sheet has been widely studied by scholars. The tightly coupled phased array antenna adopts an array-based design method, which uses limited array elements to approximate the radiation efficiency of infinite current sheets, and breaks through the limitation of array element spacing by strengthening the mutual coupling between units, thereby achieving wide scanning angle, broadband and low profile performance at the same time.

[0004] At present, the radiating metal sheets of tightly coupled phased array antennas are often printed on dielectric substrates, while research on all-metal tightly coupled phased array antennas is relatively lacking. Compared with dielectric plate printed antennas, all-metal antennas have the advantages of high power resistance and stronger mechanical stability, which makes all-metal phased array antennas have greater application advantages in certain special fields, such as electronic countermeasure systems and high-speed aircraft. Therefore, the research on all-metal tightly coupled phased array antennas is of great significance. Summary of the invention

[0005] The goal of the present invention is to make up for the lack of all-metal tightly coupled phased array antenna technology and to realize an all-metal cast integrated tightly coupled array that can achieve broadband, wide scanning angle and low profile.

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

[0007] The present invention is mainly composed of a radiation structure, a feeding structure and a wide-angle matching layer. The radiation structure is in the form of a metal dipole antenna 1. Open ring structures 2 are added on both sides of the dipole 1. The open ring structure 2 can introduce parallel capacitance to the antenna, thereby improving the impedance matching within the working frequency band. A first metal cavity 5 is opened below the dipole 1, and a metal plate 3 perpendicular to the dipole is added. The first metal cavity 5 and the metal plate 3 introduce coupling capacitance between adjacent dipoles 1, thereby expanding the low-frequency bandwidth of the antenna; at the same time, the addition of the metal plate 3 can suppress the common-mode resonance of the antenna.

[0008] Since the radiation impedance of the dipole antenna is relatively high, it is a major difficulty of the present invention to realize broadband impedance transformation in the all-metal structure. In order to solve this problem, the feeding structure of the present invention draws on the feeding method of the Vivaldi antenna, and realizes the feeding of antenna energy by opening an open slot 6 in the metal structure and connecting the inner conductor and outer conductor of the coaxial line 8 to the upper and lower ends of the open slot 6 respectively; the left end of the open slot 6 is a second metal cavity 4 opened, and the function of the second metal cavity 4 is to improve the input impedance and optimize the matching; the width of the open slot 6 gradually narrows from the feeding end to the radiation end, thereby realizing the impedance transformation from low to high.

[0009] In order to realize the wide scanning angle in a wide frequency band, a wide-angle matching layer is loaded on the all-metal phased array antenna. The wide-angle matching layer adopts the form of a metasurface, and the antenna radiation impedance is matched with the free space wave impedance by printing a split ring and its complementary cross-shaped structure 10 on a dielectric substrate 9, thereby optimizing the active standing wave during large-angle scanning.

[0010] The innovation of the present invention lies in:

[0011] First, the feeding of the all-metal dipole is realized by using an open slot structure with variable width, which solves the difficulty of impedance matching of the dipole antenna in the design process of the all-metal tightly coupled phased array antenna. Second, the real and imaginary parts of the dipole antenna impedance are balanced by loading an open ring next to the dipole and loading a metasurface with a complementary structure, achieving the characteristics of broadband and wide scanning angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is an overall view of the present invention; FIG. 2(a) is a feeding structure and a radiation structure of the present invention, FIG. 2(b) is a front view thereof, FIG. 2(c) is a side view thereof, FIG. 2(d) is a top view thereof, and FIG. 2(e) is a bottom view thereof; FIG. 3(a) is an overall view of a wide-angle matching layer of the present invention, and FIG. 3(b) is a top view thereof; Figure 4It is the active standing wave of the side-fire, E-plane scanning of 45 degrees and H-plane scanning of 45 degrees simulated under infinite boundary conditions of the present invention; Figure 5(a) is the E-plane scanning pattern simulated when the present invention forms a 10×10 array, and Figure 5(b) is the H-plane scanning pattern simulated when the present invention forms a 10×10 array.

[0013] 1 is a metal dipole, 2 is an open ring structure, 3 is a metal plate, 4 is a second metal cavity, 5 is a first metal cavity, 6 is an open slot, 7 is a floor, 8 is a coaxial line, 9 is a dielectric plate, and 10 is a split ring and its complementary cross structure. Specific implementation plan

[0014] In order to make the objectives, technical solutions and innovative points of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples.

[0015] Figure 1 This is the overall structure of the present invention, which includes a wide-angle matching layer, a radiation structure and a feeding structure from top to bottom.

[0016] FIG2(a) shows the feeding structure and the radiation structure of the present invention, FIG2(b) is its front view, FIG2(c) is its side view, FIG2(d) is its top view, and FIG2(e) is its bottom view. 1 is a metal dipole, and the middle of the dipole is arc-shaped, which can be realized by milling a rectangular metal block. The width w of the metal dipole 1 is 4 3mm; 2 is an open ring structure connecting the metal dipole, and the open ring 2 passes through a width w 5 A metal block of 5 mm is connected to dipole 1, and the width of the open ring is L 3 is 20 mm, and the length of one arm is L 2 10mm, height h 2 The width and arm length of the open ring determine the size of the reactance introduced to the radiation impedance. 3 is a metal plate, which is perpendicular to the dipole and has a height of h 1 The lower end is grounded, and the upper end is spaced h from the first metal cavity 5 opened below the dipole. 6 =0.5mm, which can be adjusted by h 6 The size of the coupling capacitance between adjacent dipoles is controlled by the size of the first metal cavity 5. 3 6 is an open slot opened in the metal structure, and the width of the open slot increases from the coaxial line end to the dipole end, which are w 1 =1.1mm, w 2 =1.2mm, w 3 =1.6mm, so that the energy is less reflected during transmission. 4 is the second metal cavity opened on the left side of the coaxial line. The height h of cavity 4 is 412mm, h 4 The size of affects the reactance introduced in the feed structure. By optimizing it, better impedance matching can be achieved. 7 is the antenna floor, and its length and width are both L 1 =29.2mm, the function of the floor 7 is to suppress the back radiation and improve the antenna gain. 8 is the coaxial port of the antenna, which is used to feed energy to the antenna.

[0017] FIG3(a) shows the overall view of the wide-angle matching layer of the present invention, and FIG3(b) is its top view. The wide-angle matching layer of the present invention adopts a metasurface structure, and the dielectric block 9 adopts TP-1 / 2 material, whose relative dielectric constant is 3, relative magnetic permeability is 1.0000004, loss tangent is 0.001, and the length and width of the dielectric block are consistent with the size of the floor, which is L 1 , height h 5 The upper surface of the medium 9 is printed with split rings and their cross-shaped complementary structures 10. As can be seen from FIG3 , the split rings and their complementary structures are staggered. The outer radius r of the split rings is 1 is 3.45mm, inner radius r 2 is 1.45 mm, and the length of the cross-shaped structure is the outer radius r 1 twice its width w 6 It is 0.4mm.

[0018] Figure 4 The active standing waves of the tightly coupled phased array antenna in the side-firing, E-plane 45-degree scanning and H-plane 45-degree scanning under infinite boundary conditions are demonstrated. It can be seen that in the frequency band of 0.8 GHz to 4.2 GHz, the active standing waves of the present invention are less than 3 when side-firing and E-plane scanning at 45 degrees, achieving a 5.25:1 octave bandwidth; when the H-plane scans at 45 degrees, the active standing waves are less than 3.2 in the frequency band of 0.8 GHz to 3.8 GHz (4.75:1), which also meets the requirements for active standing waves of tightly coupled phased array antennas in engineering.

[0019] Figure 5(a) shows the scanning pattern of the E-plane beam within the range of ±45 degrees at 3 GHz when the present invention forms a 10×10 array, and Figure 5(b) shows the scanning pattern of the H-plane beam within the range of ±45 degrees at the same frequency. It can be seen that after the present invention forms a 10×10 array, it can achieve ±45° beam scanning on the E-plane and H-plane, while only introducing low gain loss. The profile height of the present invention is 0.13 times the low-frequency wavelength, realizing the low profile characteristics of the antenna.

[0020] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may 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 a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A tightly coupled phased array antenna, consisting of 10×10 antenna units, wherein the antenna unit includes a radiation structure, a feeding structure and a wide-angle matching layer, characterized in that: The wide-angle matching layer is located at the top of the antenna, and includes a dielectric plate (9), a split ring and a cross-complementary structure (10); the radiation structure is located below the wide-angle matching layer, and includes a metal dipole (1), an open ring structure (2), a metal plate (3), and a first metal cavity (5); the feeding structure is located below the radiation structure, and includes a second metal cavity (4), an open slot (6), a floor (7), and a coaxial line (8); the radiation structure and the feeding structure of the antenna unit are in an all-metal casting integrated form; The portion where the metal dipole (1) is connected to the feeding structure is arc-shaped; the open ring structure (2) is located on both sides of the metal dipole (1) and is connected via a metal block; the first metal cavity (5) is opened below the dipole; the metal plate (3) is perpendicular to the metal dipole (1), its lower end is grounded, and its upper end is spaced 0.5 mm from the upper edge of the first metal cavity (5), thereby introducing capacitive coupling between adjacent dipoles; The open slot (6) is located below the first metal cavity (5), and its width increases from the end of the coaxial line (8) to the end of the dipole (1) to achieve impedance matching; the inner conductor of the coaxial line (8) is connected to the upper end of the open slot, and the outer conductor is connected to the lower end of the open slot to achieve energy feeding; the second metal cavity (4) is opened on the left side of the coaxial line (8) to balance the input impedance of the antenna and achieve impedance matching; the floor (7) is located at the bottom of the antenna to suppress back radiation and improve gain.

2. The tightly coupled phased array antenna according to claim 1, characterized in that: The split ring and its cross complementary structure (10) are printed on the upper surface of the medium plate (9), and two complementary structures in the split ring and its cross complementary structure (10) are distributed in a staggered manner.

3. The tightly coupled phased array antenna according to claim 1, characterized in that: The antenna unit has a lateral dimension of 29.2 mm×29.2 mm and a cross-sectional height of 50 mm.

4. The tightly coupled phased array antenna according to claim 1, characterized in that: The widths of the open slot (6) are 1.1 mm, 1.2 mm and 1.6 mm respectively from the coaxial line end to the dipole end.

5. The tightly coupled phased array antenna according to claim 1 or claim 2, characterized in that: The dielectric plate (9) has a relative dielectric constant of 3, a relative magnetic permeability of 1.0000004, a loss tangent of 0.001, a lateral dimension of the dielectric block of 29.2 mm×29.2 mm, and a height of 15 mm; in the split ring and its cross complementary structure (10), the outer radius of the split ring is 3.45 mm, the inner radius is 1.45 mm, and the line width of the cross structure is 0.4 mm.

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