Ultra-wideband scanning angle plane tightly coupled array antenna

Abstract

The application provides an ultra-wideband scanning angle planar tightly coupled array antenna, which comprises a plurality of antenna units arranged periodically; the antenna unit comprises, from top to bottom, a coating layer, a radiation layer, an absorbing layer and a metal ground plate which are arranged in sequence and are not in contact; the radiation layer comprises a radiation layer dielectric board and radiation patches and coupling patches printed on the upper and lower surfaces of the radiation layer dielectric board; the radiation patches adopt an interdigital dual-polarized dipole structure; the coupling patches are composed of a circular metal patch and four quasi-isosceles trapezoidal metal patches which are uniformly distributed on the circumference of the circular metal patch; and the absorbing layer comprises an absorbing layer dielectric board and a ring-shaped thin film resistor printed on the upper surface of the absorbing layer dielectric board. The coupling patches can increase the coupling capacitance between the dipoles, thereby offsetting the inductive reactance introduced by the ground plate, suppressing the resonance points in the frequency band, and the thin film resistor in the absorbing layer can convert the energy of the incident electromagnetic wave 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 application belongs to the technical field of antennas and relates to an ultra-wideband scanning angle planar tight-coupling array antenna, which can be applied to wireless systems such as communication and radar. BACKGROUND

[0002] With the continuous development of antenna technology, the design of antennas tends to be ultra-wideband, low profile, wide scanning angle scanning and the like, and the traditional array antenna cannot well meet these conditions. The tight-coupling array antenna is a new type of phased array antenna proposed in recent years, compared with the traditional array antenna which needs to consider the coupling effect between elements, the tight-coupling array antenna uses the strong mutual coupling effect between antenna elements to widen the bandwidth, and has the advantages of ultra-wideband, low profile, wide scanning angle and the like.

[0003] The tight-coupling array antenna with a planar structure has the characteristics of low profile and easy to conform, but it is difficult to realize the performance of wide-angle beam scanning while having a relatively wide working frequency band. Therefore, it is of great significance to study the ultra-wideband scanning angle planar tight-coupling array antenna in the field of radar antennas.

[0004] A patent application with the application publication number CN 117525859 A and the name of "Planar modular ultra-wideband tight-coupling antenna with double-ridge waveguide structure and antenna array" discloses a planar modular ultra-wideband tight-coupling antenna with a double-ridge waveguide structure, which comprises a radiation patch layer, a coupling patch layer, a first ridge waveguide structure, a second ridge waveguide structure, a metal bottom plate and a feed structure outer conductor. 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 bottom plate and the radiation patch layer. The first ridge waveguide structure is located directly below the radiation patch layer, and the second ridge waveguide structure is located on the diagonal of the pair of metal dipole patches. The feed structure outer conductor is located at the lower end of the metal bottom plate and feeds the radiation patch layer through the metal hole located in the first ridge waveguide structure. The application effectively expands the high frequency bandwidth of the antenna and significantly improves the performance of the antenna at a large scanning angle. However, because the coupling patch layer of the application has limited effect on increasing the capacitive coupling between the dipoles, it cannot offset the inductive reactance introduced by the metal bottom plate, and the double-ridge waveguide structure of the application cannot eliminate the common mode resonance in the frequency band, resulting in that the working bandwidth is difficult to be further expanded. SUMMARY

[0005] The purpose of the application is to overcome the defects of the prior art, and provide an ultra-wideband scanning angle planar tight-coupling array antenna, which aims to expand the working bandwidth of the antenna while ensuring the wide scanning angle of the antenna.

[0006] In order to achieve the above object, the present application adopts the following technical scheme: a plurality of antenna units arranged periodically; the antenna unit comprises a radiation layer 2 and a metal floor 4 arranged from top to bottom and not in contact; a coating 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 adopt a double-polarized dipole structure in an interdigital shape, each dipole is fed by a feed 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 uniformly distributed on the circumference thereof; a wave-absorbing layer 3 is arranged between the radiation layer 2 and the metal floor 4, and the wave-absorbing layer 3 comprises a wave-absorbing layer dielectric plate 31 and a ring-shaped thin film resistor 32 printed on the upper surface thereof.

[0007] As an optimization, the coating layer 1 adopts a dielectric plate with a square plate shape; the radiation layer dielectric plate 21, the wave-absorbing layer dielectric plate 31 and the metal floor 4 have the same plate size as the coating layer 1.

[0008] As an optimization, the radiation layer dielectric plate 21 is provided with a circular arc cut corner at each of the four corners located at the spatial position formed by the two dipole structures, and the radiation layer dielectric plate 21 is further provided with mounting holes for fixing the upper ends of the two feed baluns 5.

[0009] As an optimization, the radiation patch 22, wherein the double-polarized dipole structure is formed by two pairs of interdigital dipole arms vertically intersecting each other, each interdigital dipole arm is composed of a quasi-isosceles trapezoidal metal patch and an isosceles triangular metal patch with a bottom edge spliced with the lower base of the quasi-isosceles trapezoidal metal patch, 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, wherein the quasi-isosceles trapezoidal metal patch and the quasi-isosceles trapezoidal metal patch in each interdigital dipole arm all adopt a structure with parallel upper and lower bases and concave curves as the two waists.

[0011] As an optimization, the radiation patch 22, wherein 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 coupling patch 23, wherein the center is located at the projection position of the center of the radiation patch 22.

[0013] As an optimization, the wave-absorbing layer dielectric plate 31 is provided with a rectangular through hole for the two feed baluns 5 to pass through, and the ring-shaped thin film resistor 32 printed on the upper surface of the wave-absorbing layer dielectric plate 31 is located at the four peripheral edges of the wave-absorbing layer dielectric plate 31.

[0014] As optimization, the feeding bar 5 comprises a feeding layer dielectric plate 51, and a microstrip exponential taper feeding line 52 printed on one plate surface and a microstrip exponential taper ground plate 53 printed on another plate surface, the microstrip exponential taper feeding line 52 and the microstrip exponential taper ground plate 53 both adopt an exponential taper line structure with upper narrow and lower wide, and the width of the microstrip exponential taper feeding line 52 is smaller than that of the microstrip exponential taper ground plate 53, wherein the upper ends of the microstrip exponential taper feeding line 52 and the microstrip exponential taper ground plate 53 are connected with the short sides of quasi-isosceles trapezoids in the two pairs of interdigital dipole arms, and the lower ends are connected with the coaxial probes 6 and the metal ground plate 4 respectively.

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

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

[0017] 1. The coupling patch of the present application is composed of a circular metal patch and four quasi-isosceles trapezoidal metal patches evenly distributed on the circumference of the circular metal patch, which can increase the coupling capacitance between the dipoles, thereby offsetting the inductive reactance introduced by the ground plate and suppressing the resonance points in the frequency band, thus effectively widening the working bandwidth compared with the prior art.

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

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

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

[0021] Figure 3 It is a schematic diagram of the structure of the radiation layer of the embodiment of the present application.

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

[0023] Figure 5 It is a schematic diagram of the structure of the feeding bar of the present application.

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

[0025] The present application will be further described in detail below in combination with the drawings and specific embodiments.

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

[0027] With reference to Figure 1 , the antenna unit comprises, from top to bottom, a cladding layer 1, a radiation layer 2, an absorbing layer 3 and a metal floor 4 arranged successively and not in contact; the cladding 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 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 adopt a cross-shaped dual-polarized dipole structure, each dipole is fed by a feed balun 5 and a coaxial probe 6 connected thereto, the coupling patches 23 are composed of a circular metal patch and four quasi-isosceles trapezoidal metal patches uniformly distributed on the circumference thereof; the absorbing layer 3 comprises an absorbing layer dielectric plate 31 and a ring-shaped thin film resistor 32 printed on the upper surface thereof; the metal floor 4 is provided with a circular through hole for the 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 cladding layer 1.

[0028] With reference to Figure 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 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 the embodiment is as shown in Figure 3As shown, four corners of the antenna unit are provided with circular arc cut corners, and the four corners are located in the spatial positions formed by two dipole structures. After the antenna unit is arranged periodically, a cylindrical cavity is formed, and the central axis of the cylindrical cavity is located on the diagonal line of the center point of the radiation patch 22. The cylindrical cavity can reduce the equivalent dielectric constant of the radiation layer dielectric plate 21, thereby suppressing the surface wave and expanding the working bandwidth. The radiation layer dielectric plate 21 is further provided with mounting holes for fixing the upper ends of the two feed baluns 5. The dual-polarized dipole structure in the radiation patch 22 is formed by two pairs of perpendicular interdigital dipole arms. Each interdigital dipole arm is composed of a quasi-isosceles trapezoidal metal patch and an isosceles triangular metal patch spliced with the lower base of the quasi-isosceles trapezoid. Two rectangular protrusions are arranged on each leg of the isosceles triangular metal patch, and a coupling capacitor is formed between each rectangular protrusion. The quasi-isosceles trapezoidal metal patch in the coupling patch 23 and the quasi-isosceles trapezoidal metal patch in each interdigital dipole arm are both in a structure with parallel upper and lower bases and two concave legs. The area formed by the four isosceles triangular metal patches provided with rectangular protrusions in the radiation patch 22 is smaller than the area of the circular metal patch in the coupling patch 23. The center of the coupling patch 23 is located at the projection position of the center of the radiation patch 22 and does not contact the feed balun 5. The height of the quasi-isosceles trapezoidal metal patch spliced on the circumference of the coupling patch 23 is smaller than the height of the quasi-isosceles trapezoidal metal patch in the interdigital dipole arm. The coupling patch 23 can increase the coupling capacitance between the dipoles, thereby canceling the inductive reactance introduced by the metal floor 4, suppressing the resonance points in the frequency band, and expanding the working bandwidth.

[0030] Referring to Figure 4 The wave-absorbing layer 3 includes a wave-absorbing layer dielectric plate 31 and a ring-shaped thin film resistor 32 printed on the upper surface thereof. The wave-absorbing layer dielectric plate 31 is made of F4B material with a dielectric constant of 2.65 and a thickness of 1 mm. Rectangular through holes are provided on the wave-absorbing layer dielectric plate 31 for the two feed baluns 5 to pass through. The ring-shaped thin film resistor 32 printed on the upper surface of the wave-absorbing layer dielectric plate 31 is located at the four peripheral edges of the wave-absorbing layer dielectric plate 31. The resistance value of the thin film resistor 32 is 50 ohm / sq, and the width is 0.5 mm. The wave-absorbing layer 3 can convert the energy of the incident electromagnetic wave into heat, thereby dissipating and attenuating the energy and further expanding the working bandwidth.

[0031] Referring to Figure 5The feeding bar 5 includes a feeding layer dielectric plate 51, a microstrip exponential gradient feeding line 52 printed on one plate surface and a microstrip exponential gradient floor 53 printed on another plate surface, and the feeding bar 5 is in contact with the wave-absorbing layer dielectric plate 31 and not in contact with the film resistor 32; the feeding layer dielectric plate 51 is made of F4B material, has a dielectric constant of 2.65 and a thickness of 0.5 mm; the microstrip exponential gradient feeding line 52 and the microstrip exponential gradient floor 53 are both in the form of an exponential gradient line structure with a narrow upper end and a wide lower end, and the width of the microstrip exponential gradient feeding line 52 is smaller than that of the microstrip exponential gradient floor 53, wherein the upper ends of the microstrip exponential gradient feeding line 52 and the microstrip exponential gradient floor 53 are connected to the short sides of the quasi-isosceles trapezoidal shapes in the two pairs of interdigital dipole arms, and the lower ends are connected to the coaxial probe 6 and the metal floor 4, respectively; the characteristic impedance of the upper end and the lower end of the microstrip exponential gradient feeding line 52 is 120 ohm and 50 ohm, respectively.

[0032] The working principle of the application is that the antenna unit feeds the interdigital dual-polarized dipole through the feeding bar 5, so that the interdigital dual-polarized dipole radiates outward, the coupling capacitance between the rectangular protrusions on the isosceles triangular metal patches of each dipole arm is formed, and the partial inductive reactance introduced by the metal floor is offset, so as to realize the super-wideband scanning performance of the antenna; in order to improve the impedance matching when the antenna scans a wide scanning angle, the cover layer 1 is arranged above the radiation layer 2; the wave-absorbing layer 3 is arranged below the radiation layer 2, can convert the energy of the incident electromagnetic wave into heat energy, so that the energy is dissipated and attenuated, the resonance points in the frequency band are suppressed, and the antenna unit realizes a wider bandwidth; the center of the coupling patch 23 is located at the projection position of the center of the radiation patch 22, which can increase the coupling capacitance between the dipoles, so as to offset the inductive reactance introduced by the metal floor 4, suppress the resonance points in the frequency band, and further expand the working bandwidth of the antenna.

[0033] The technical effects of the application are further described below in combination with simulation results:

[0034] 1. Experimental conditions and contents:

[0035] The standing wave ratio of the E-plane and H-plane scanning angle of 0-60° in the 2-20GHz frequency band is simulated by using the simulation software ANSYS Electronics Desktop, and the results are shown in Figure 6

[0036] 2. Analysis of experimental results:

[0037] Referring to Figure 6 , the abscissa is the frequency, ranging from 2GHz to 20GHz; and the ordinate is the standing wave ratio, ranging from 1 to 6. Figure 6 (a) and Figure 6 ​(b) are the E-plane and H-plane standing wave ratios at the scanning angle of 0-60°, respectively. It can be seen from the figure that the application can realize the working bandwidth of 4-18 GHz when the standing wave ratio is lower than 3, which is superior to the prior art of 8-27 GHz.

Claims

1. An ultra-wideband, wide-scan angle planar, tightly coupled array antenna comprising a plurality of antenna elements arranged periodically; said antenna elements comprising a radiating layer (2) and a metallic ground plane (4) arranged one above the other and not in contact; characterized in that, The radiation layer (2) is provided with a cover layer (1) above; 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) adopt an interdigital dual-polarized dipole structure, each dipole is fed by a feed balun (5) and a coaxial probe (6) connected thereto; the coupling patches (23) are composed of a circular metal patch and four quasi-isosceles trapezoidal metal patches uniformly distributed on the circumference thereof; a wave absorbing layer (3) is arranged between the radiation layer (2) and a metal ground plate (4), and the wave absorbing layer (3) comprises a wave absorbing layer dielectric plate (31) and a ring-shaped thin film resistor (32) printed on the upper surface thereof.

2. The antenna of claim 1, wherein: The cover layer (1) adopts a dielectric plate with a square plate shape; the radiation layer dielectric plate (21), the wave absorbing layer dielectric plate (31) and the metal ground plate (4) have the same plate size as the cover layer (1).

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

4. The antenna of claim 1, wherein: The dual-polarized dipole structure in the radiation patch (22) is formed by two pairs of vertically intersecting interdigital dipole arms, each interdigital dipole arm is composed of a quasi-isosceles trapezoidal metal patch and an isosceles triangular metal patch with a bottom edge spliced with the lower base of the quasi-isosceles trapezoidal, 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 quasi-isosceles trapezoidal metal patch in the coupling patch (23) and the quasi-isosceles trapezoidal metal patch in each interdigital dipole arm all adopt a structure with parallel upper and lower bases and concave waists.

6. The antenna according to claim 5, characterized in that: The area formed by the four isosceles triangular metal patches provided with rectangular protrusions in the radiation patch (22) 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 a rectangular through hole for the two feed baluns (5) to pass through, and the ring-shaped thin film resistor (32) printed on the upper surface of the wave absorbing layer dielectric plate (31) is located at the four peripheral edges of the wave absorbing layer dielectric plate (31).

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

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

Images