Ultra-wide-band wide-scanning-angle planar tight coupling array antenna

Abstract

The invention provides an ultra-wide-band wide-scanning-angle planar tight coupling array antenna. The antenna comprises a plurality of antenna units which are periodically arranged; the antenna unit comprises a coating layer, a radiation layer, a wave absorbing layer and a metal floor which are sequentially arranged from top to bottom and are not in contact; the radiation layer comprises a radiation layer dielectric plate, and a radiation patch and a coupling patch which are printed on the upper surface and the lower surface of the radiation layer dielectric plate; the radiation patch adopts an interdigital dual-polarization dipole structure; the coupling patch consists of a circular metal patch and four quasi-isosceles trapezoid metal patches which are spliced on the circumference of the circular metal patch and are uniformly distributed; the wave-absorbing layer comprises a wave-absorbing layer dielectric plate and an annular thin-film resistor printed on the upper surface of the wave-absorbing layer dielectric plate. The coupling patch can increase the coupling capacitance between the dipoles so as to offset inductive reactance introduced by the floor and suppress resonance points in a frequency band, and the thin-film resistor in the wave absorbing layer can convert energy of incident electromagnetic waves into heat energy, so that the energy is dissipated and attenuated, the resonance points in the frequency band are suppressed, and the working bandwidth is widened.

Description

Technical Field

[0001] The invention belongs to the field of antenna technology and relates to an ultra-wide bandwidth scanning angle plane tightly coupled array antenna, which can be applied to wireless systems such as communications and radars. Background Art

[0002] With the continuous development of antenna technology, antenna design is increasingly tending towards ultra-wideband, low profile, wide scanning angle scanning, etc., while traditional array antennas cannot meet these conditions well. Tightly coupled array antenna is a new type of phased array antenna proposed in recent years. Compared with traditional array antennas that need to consider the coupling effect between units, tightly coupled array antenna uses the strong mutual coupling effect between antenna units to broaden the bandwidth, and has the advantages of ultra-wideband, low profile, wide scanning angle, etc.

[0003] The planar tightly coupled array antenna has the characteristics of low profile and easy conformality, but it is difficult to achieve large-angle beam scanning performance while having a wide operating frequency band. Therefore, the study of ultra-wide bandwidth scanning angle planar tightly coupled array antenna is of great significance in the field of radar antennas.

[0004] The patent application with application publication number CN 117525859 A and titled “Planar modular ultra-wideband tightly coupled antenna and antenna array with double-ridge waveguide structure” discloses a planar modular ultra-wideband tightly coupled antenna with double-ridge waveguide structure, comprising: a radiation patch layer, a coupling patch layer, a first ridge waveguide structure, a second ridge waveguide structure, a metal base plate, and an outer conductor of a feeding structure; the radiation patch layer is a pair of cross-placed metal dipole patches; the coupling patch layer is placed above the radiation patch layer; the first ridge waveguide structure and the second ridge waveguide structure are located between the metal base plate and the radiation patch layer; the first ridge waveguide structure is located directly above the radiation patch layer. Below, the second ridge waveguide structure is located at the diagonally opposite corners of a pair of metal dipole patches; the outer conductor of the feeding structure is located at the lower end of the metal base plate, and the radiation patch layer is fed through the metal hole located in the first ridge waveguide structure. This invention effectively expands the high-frequency bandwidth of the antenna and significantly improves the performance of the antenna at large scanning angles. However, because the coupling patch layer of this invention has limited effect on increasing the capacitive coupling between dipoles, it cannot offset the inductive reactance introduced by the metal base plate, and the double-ridge waveguide structure of this invention cannot eliminate common-mode resonance within the frequency band, which makes it difficult to further widen its working bandwidth. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide an ultra-wide bandwidth scanning angle plane tightly coupled array antenna, aiming to ensure a wide scanning angle of the antenna while broadening the working bandwidth of the antenna.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme including a plurality of antenna units arranged periodically; the antenna unit includes a radiation layer 2 and a metal floor 4 arranged from top to bottom and not in contact with each other; a covering layer 1 is arranged above the radiation layer 2; the radiation layer 2 includes a radiation layer dielectric plate 21 and a radiation patch 22 and a coupling patch 23 printed on the upper and lower surfaces thereof, the radiation patch 22 adopts an interdigitated dual-polarization dipole structure, and each dipole is fed through a feeding balun 5 and a coaxial probe 6 connected thereto; the coupling patch 23 is composed of a circular metal patch and four quasi-isosceles trapezoidal metal patches spliced ​​and evenly distributed on its circumference; an absorbing layer 3 is arranged between the radiation layer 2 and the metal floor 4, and the absorbing layer 3 includes an absorbing layer dielectric plate 31 and a ring-shaped thin film resistor 32 printed on its upper surface.

[0007] As an optimization, the cladding 1 is a dielectric plate with a square surface shape; the radiation layer dielectric plate 21 , the absorbing layer dielectric plate 31 , and the metal floor 4 have the same surface size as that of the cladding 1 .

[0008] As an optimization, the four corners of the radiation layer dielectric plate 21 are located in the space formed by the two dipole structures and are each provided with an arc cut corner. The radiation layer dielectric plate 21 is also provided with mounting holes for fixing to the upper ends of the two feeding baluns 5 .

[0009] As an optimization, the radiation patch 22, wherein the dual-polarized dipole structure is formed by two pairs of interdigitated dipole arms vertically crossed, each interdigitated dipole arm is composed of a quasi-isosceles trapezoidal metal patch and an isosceles triangular metal patch whose base is spliced ​​with the lower base of the quasi-isosceles trapezoid, and a plurality of rectangular protrusions are arranged on the two waists of the isosceles triangular metal patch.

[0010] As an optimization, the coupling patch 23, the quasi-isosceles trapezoidal metal patch therein, and the quasi-isosceles trapezoidal metal patch in each interdigitated dipole arm all adopt a structure in which the upper and lower bases are parallel and the two waists are concave curves.

[0011] As an optimization, the radiation patch 22 , in which the area formed by the four isosceles triangular metal patches provided with rectangular protrusions is smaller than the area of ​​the circular metal patch in the coupling patch 23 .

[0012] As an optimization, the center of the coupling patch 23 is located at the projection position of the center of the radiation patch 22 .

[0013] As an optimization, the absorbing layer dielectric plate 31 is provided with rectangular through holes for two feeding baluns 5 to pass through, and the annular thin film resistors 32 printed on the upper surface of the absorbing layer dielectric plate 31 are located on the four edges of the absorbing layer dielectric plate 31 .

[0014] As an optimization, the feeding balun 5 includes a feeding layer dielectric board 51, a microstrip exponential gradient feed line 52 printed on one board surface, and a microstrip exponential gradient floor 53 on another board surface. The microstrip exponential gradient feed line 52 and the microstrip exponential gradient floor 53 both adopt an exponential gradient line structure that is narrow at the top and wide at the bottom, and the width of the microstrip exponential gradient feed line 52 is smaller than the microstrip exponential gradient floor 53. The upper ends of the microstrip exponential gradient feed line 52 and the microstrip exponential gradient floor 53 are both connected to the short sides of the quasi-isosceles trapezoid in the two pairs of interdigitated dipole arms, and the lower ends are respectively connected to the coaxial probe 6 and the metal floor 4.

[0015] As an optimization, the metal floor 4 is provided with circular through holes for two coaxial probes 6 to pass through.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The coupling patch of the present invention is composed of a circular metal patch and four quasi-isosceles trapezoidal metal patches evenly distributed on its circumference, which can increase the coupling capacitance between dipoles, thereby offsetting the inductive reactance introduced by the floor and suppressing the resonance point within the frequency band. Compared with the prior art, it effectively broadens the working bandwidth.

[0018] 2. The thin film resistor in the wave absorbing layer of the present invention can convert the energy of the incident electromagnetic wave into heat energy, so that the energy is dissipated and attenuated, suppressing the resonance point in the frequency band, and further broadening the working bandwidth compared with the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the antenna unit of the present invention.

[0020] Figure 2 It is a schematic structural diagram of the radiation layer of the present invention.

[0021] Figure 3 Schematic diagram of the structure of the radiation layer according to an embodiment of the present invention.

[0022] Figure 4 It is a schematic structural diagram of the wave absorbing layer of the present invention.

[0023] Figure 5 It is a structural schematic diagram of the feeding balun of the present invention.

[0024] Figure 6 It is a standing wave ratio curve diagram of the present invention in the frequency band range of 2-20 GHz when the scanning angles of the E-plane and the H-plane are 0-60°. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0026] An ultra-wide bandwidth scanning angle plane tightly coupled array antenna comprises a plurality of periodically arranged antenna units.

[0027] Reference Figure 1 The antenna unit includes a covering layer 1, a radiation layer 2, an absorbing layer 3 and a metal floor 4 which are arranged in sequence from top to bottom and do not touch each other; the covering layer 1 is made of F4B material with a square plate shape, a dielectric constant of 2.65 and a thickness of 1 mm; the radiation layer 2 includes a radiation layer dielectric plate 21 and radiation patches 22 and coupling patches 23 printed on the upper and lower surfaces thereof, the radiation patches 22 adopt an interdigitated dual-polarized dipole structure, each dipole is fed by a feeding balun 5 and a coaxial probe 6 connected thereto, the coupling patch 23 is composed of a circular metal patch and four quasi-isosceles trapezoidal metal patches evenly distributed on its circumference; the absorbing layer 3 includes an absorbing layer dielectric plate 31 and a ring-shaped thin film resistor 32 printed on its upper surface; the metal floor 4 is provided with circular through holes for two coaxial probes 6 to pass through; the radiation layer dielectric plate 21, the absorbing layer dielectric plate 31 and the metal floor 4 have the same plate size as the covering layer 1.

[0028] Reference Figure 2 The radiation layer 2 includes a radiation layer dielectric plate 21 and radiation patches 22 and coupling patches 23 printed on the upper and lower surfaces thereof. The radiation layer dielectric plate 21 is made of F4B material with a dielectric constant of 2.65 and a thickness of 0.8 mm.

[0029] The structure of the radiation layer dielectric plate 21 in this embodiment is as follows Figure 3As shown, its four corners are located in the space formed by the two dipole structures and are each provided with an arc cut corner. The antenna units are periodically arranged to form a cylindrical cavity, and the central axis of the cylindrical cavity is located on the diagonal line where the center point of the radiation patch 22 is located. The cylindrical cavity can reduce the equivalent dielectric constant of the radiation layer dielectric plate 21, thereby suppressing surface waves and expanding the working bandwidth; the radiation layer dielectric plate 21 is also provided with mounting holes for fixing with the upper ends of the two feeding baluns 5; the radiation patch 22, wherein the dual-polarization dipole structure is formed by two pairs of interdigitated dipole arms vertically crossed, each interdigitated dipole arm is composed of a quasi-isosceles trapezoidal metal patch and an isosceles triangular metal patch whose bottom edge is spliced ​​with the lower bottom edge of the quasi-isosceles trapezoid, and each waist of the isosceles triangular metal patch is provided with two rectangular protrusions, each rectangular protrusion having a rectangular shape. shaped protrusions to form a coupling capacitor; the coupling patch 23, the quasi-isosceles trapezoidal metal patch therein, and the quasi-isosceles trapezoidal metal patch in each interdigitated dipole arm, all adopt a structure in which the upper and lower bases are parallel and the two waists are concave curves; the radiation patch 22, wherein the area formed by the four isosceles triangular metal patches with rectangular protrusions is smaller than the area of ​​the circular metal patch in the coupling patch 23; the coupling patch 23, whose center is located at the projected position of the center of the radiation patch 22 and is not in contact with the feeding balun 5, and the height of the quasi-isosceles trapezoidal metal patch spliced ​​on its circumference is smaller than the height of the quasi-isosceles trapezoidal metal patch in the interdigitated dipole arm, the coupling patch 23 can increase the coupling capacitance between the dipoles, thereby offsetting the inductive reactance introduced by the metal floor 4, suppressing the resonance point within the frequency band, and thus expanding the working bandwidth.

[0030] Reference Figure 4 The absorbing layer 3 includes an absorbing layer dielectric plate 31 and an annular thin film resistor 32 printed on its upper surface. The absorbing layer dielectric plate 31 is made of F4B material, has a dielectric constant of 2.65, and a thickness of 1 mm. A rectangular through hole for two feeding baluns 5 to pass through is arranged on it. The annular thin film resistor 32 printed on the upper surface of the absorbing layer dielectric plate 31 is located on the four edges of the absorbing layer dielectric plate 31; the resistance of the thin film resistor 32 is 50 ohm / sq, and the width is 0.5 mm; the absorbing layer 3 can convert the energy of the incident electromagnetic wave into heat energy, so that the energy is dissipated and attenuated, suppressing the resonance point in the frequency band, thereby further expanding the working bandwidth.

[0031] Reference Figure 5The feeding balun 5 includes a feeding layer dielectric plate 51, a microstrip index gradient feed line 52 printed on one plate surface and a microstrip index gradient floor 53 on another plate surface. The feeding balun 5 is in contact with the absorbing layer dielectric plate 31 and is not in contact with the thin film resistor 32. The feeding layer dielectric plate 51 is made of F4B material with a dielectric constant of 2.65 and a thickness of 0.5 mm. The microstrip index gradient feed line 52 and the microstrip index gradient floor 53 both adopt an index gradient line structure with a narrow upper part and a wide lower part, and the width of the microstrip index gradient feed line 52 is smaller than that of the microstrip index gradient floor 53. The upper ends of the microstrip index gradient feed line 52 and the microstrip index gradient floor 53 are connected to the short sides of the quasi-isosceles trapezoid in the two pairs of interdigitated dipole arms, and the lower ends are respectively connected to the coaxial probe 6 and the metal floor 4; the characteristic impedances of the upper and lower ends of the microstrip index gradient feed line 52 are 120 ohm and 50 ohm, respectively.

[0032] The working principle of the present invention is that the antenna unit feeds the interdigitated dual-polarized dipole through the feeding balun 5, so that the interdigitated dual-polarized dipole radiates outward, and a coupling capacitor is formed between the rectangular protrusions on the isosceles triangle metal patch of each dipole arm, which offsets the partial inductive reactance introduced by the metal floor, thereby achieving the ultra-wideband scanning performance of the antenna; in order to improve the impedance matching of the antenna when scanning at a wide scanning angle, a covering layer 1 is arranged above the radiation layer 2; the absorbing layer 3 is located below the radiation layer 2, and can convert the energy of the incident electromagnetic wave into thermal energy, so that the energy is dissipated and attenuated, suppressing the resonance point in the frequency band, so that the antenna unit achieves a wider bandwidth; the center of the coupling patch 23 is located at the projected position of the center of the radiation patch 22, which can increase the coupling capacitance between the dipoles, thereby offsetting the inductive reactance introduced by the metal floor 4, suppressing the resonance point in the frequency band, and further expanding the working bandwidth of the antenna.

[0033] The following is a further description of the technical effects of the present invention in conjunction with the simulation results:

[0034] 1. Experimental conditions and contents:

[0035] The simulation software ANSYS Electronics Desktop is used to simulate the standing wave ratio of the E-plane and H-plane of the present invention in the frequency band of 2-20 GHz when the scanning angle is 0-60°. The results are as follows: Figure 6 shown.

[0036] 2. Experimental results analysis:

[0037] Reference Figure 6 The horizontal axis is frequency, ranging from 2-20GHz; the vertical axis is standing wave ratio, ranging from 1-6. Figure 6 (a) and Figure 6(b) are the standing wave ratios of the E-plane and the H-plane when the scanning angle is 0-60°, respectively. It can be seen from the figure that when the standing wave ratio is lower than 3, the present invention can achieve an operating bandwidth of 4-18 GHz, which is better than the 8-27 GHz of the prior art.

Claims

1. An ultra-wide bandwidth scanning angle plane tightly coupled array antenna, comprising a plurality of antenna units arranged periodically; the antenna units comprise a radiation layer (2) and a metal floor (4) arranged from top to bottom and not in contact with each other; characterized in that: A covering layer (1) is arranged above the radiation layer (2); the radiation layer (2) comprises a radiation layer dielectric plate (21) and radiation patches (22) and coupling patches (23) printed on the upper and lower surfaces thereof, the radiation patches (22) adopting an interdigitated dual-polarization dipole structure, each dipole being fed through a feeding balun (5) and a coaxial probe (6) connected thereto; the coupling patch (23) is composed of a circular metal patch and four quasi-isosceles trapezoidal metal patches spliced ​​and evenly distributed on its circumference; an absorbing layer (3) is arranged between the radiation layer (2) and the metal floor (4), the absorbing layer (3) comprising an absorbing layer dielectric plate (31) and a ring-shaped thin-film resistor (32) printed on its upper surface.

2. The antenna according to claim 1, characterized in that: The cladding (1) is a dielectric plate with a square plate surface shape; the radiation layer dielectric plate (21), the absorbing layer dielectric plate (31), and the metal floor (4) have the same plate surface size as the cladding (1).

3. The antenna according to claim 1, characterized in that: The radiation layer dielectric plate (21) has four corners located at the spatial position formed by the two dipole structures and each is provided with an arc cut corner. The radiation layer dielectric plate (21) is also provided with mounting holes for fixing to the upper ends of the two feeding baluns (5).

4. The antenna according to claim 1, characterized in that: The dual-polarized dipole structure of the radiation patch (22) is formed by two pairs of interdigitated dipole arms vertically crossing each other, each interdigitated dipole arm is composed of a quasi-isosceles trapezoidal metal patch and an isosceles triangular metal patch whose bottom edge is spliced ​​with the lower bottom edge of the quasi-isosceles trapezoid, and a plurality of rectangular protrusions are arranged on the two waists of the isosceles triangular metal patch.

5. The antenna according to claim 4, characterized in that: The coupling patch (23), the quasi-isosceles trapezoidal metal patch therein, and the quasi-isosceles trapezoidal metal patch in each interdigitated dipole arm all adopt a structure in which the upper and lower bases are parallel and the two waists are concave curves.

6. The antenna according to claim 5, characterized in that: In the radiation patch (22), the area formed by four isosceles triangular metal patches provided with rectangular protrusions is smaller than the area of ​​the circular metal patch in the coupling patch (23).

7. The antenna according to claim 6, characterized in that: The center of the coupling patch (23) is located at the projection position of the center of the radiation patch (22).

8. The antenna according to claim 7, characterized in that: The wave absorbing layer dielectric plate (31) is provided with rectangular through holes for two feeding baluns (5) to pass through, and the annular thin film resistors (32) printed on the upper surface of the wave absorbing layer dielectric plate (31) are located on the four edges of the wave absorbing layer dielectric plate (31).

9. The antenna according to claim 8, characterized in that: The feeding balun (5) comprises a feeding layer dielectric board (51), a microstrip exponential gradient feed line (52) printed on one board surface, and a microstrip exponential gradient floor (53) printed on another board surface. The microstrip exponential gradient feed line (52) and the microstrip exponential gradient floor (53) both adopt an exponential gradient line structure that is narrow at the top and wide at the bottom, and the width of the microstrip exponential gradient feed line (52) is smaller than that of the microstrip exponential gradient floor (53). The upper ends of the microstrip exponential gradient feed line (52) and the microstrip exponential gradient floor (53) are both connected to the short sides of the quasi-isosceles trapezoids in the two pairs of interdigitated dipole arms, and the lower ends are respectively connected to the coaxial probe (6) and the metal floor (4).

10. The antenna according to claim 1, characterized in that: The metal floor (4) is provided with circular through holes for two coaxial probes (6) to pass through.

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