Ultra-wideband circularly polarized millimeter-wave communication array antenna based on hollow waveguide

Abstract

The present invention discloses an ultra-wideband circularly polarized millimeter wave communication array antenna based on a hollow waveguide, comprising a radiation layer, a coupling layer, a SICL feeding network layer, a connector and an absorber layer, wherein the SICL feeding network layer comprises a suspended microstrip line and a metal through hole; the radiation layer comprises a circularly polarized antenna subarray, i.e., 16 radiation apertures; the absorber layer comprises three 1×10 absorber line arrays, i.e., 30 absorber units. The impedance relative bandwidth and axial ratio relative bandwidth of the present invention are both greater than 49%. From 19 to 31 GHz, the input reflection coefficient is better than ‑15 dB, and the antenna efficiency exceeds 80% in the entire working band. In the range of 19‑31 GHz, the peak gain of the circular polarization varies between 18.0 and 21.9 dBi. The present invention can realize the design of wide bandwidth and wide axial ratio of waveguide antenna, and can be applied to millimeter wave communication.

Description

Technical Field

[0001] The invention relates to the technical field of antennas, in particular to the technical field of circularly polarized antennas based on hollow waveguides. Background Art

[0002] In order to cope with the complex environment in future millimeter wave communications, a stable antenna form is needed. The mainstream solution is to use substrate integrated waveguide structure and hollow waveguide structure. Due to the large dielectric loss in the millimeter wave frequency band, in order to increase the efficiency of the array antenna, we adopt a hollow waveguide structure. It can be processed using a hard alloy structure, and it is possible to consider designing efficient antenna arrays because they can ignore the dielectric loss problem. It has a place in both the military and civilian fields, and with the development needs of various fields, it has also indirectly promoted the continuous development of waveguide antennas. Summary of the invention

[0003] The purpose of the present invention is to provide an ultra-wideband circularly polarized millimeter wave communication array antenna based on a hollow waveguide, which can be mass-produced by using a CNC machine tool to perform metal milling technology, and has the advantages of high efficiency, stable performance and low cost, solving the problem that millimeter wave communication can work simultaneously within a wider frequency range.

[0004] The technical solution for achieving the purpose of the present invention is: an ultra-wideband circularly polarized millimeter-wave communication array antenna based on a hollow waveguide, comprising a radiation layer, a coupling layer, a SICL feeding network layer, a connector and an absorber layer, wherein the radiation layer, the coupling layer and the SICL feeding network layer are arranged in sequence from top to bottom, and the SICL feeding network layer comprises a suspended microstrip line and a metal through-hole; the radiation layer comprises a circularly polarized antenna subarray, i.e., 16 radiation apertures; the absorber layer comprises three 1×10 absorber line arrays, i.e., 30 absorber units.

[0005] Compared with the prior art, the significant advantages of the present invention are: it can realize the wide-band and wide-axis ratio design of the hollow waveguide antenna, and it has a stable structure and a low profile, and is suitable for millimeter wave communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a schematic diagram of the ultra-wideband circularly polarized waveguide array antenna based on millimeter wave communication in the present invention.

[0007] Figure 2 It is a schematic diagram of the circular polarization subarray model of the radiation layer in the present invention.

[0008] Figure 3 It is a schematic diagram of the unit structure model of the absorber layer in the present invention.

[0009] Figure 4 It is a schematic diagram of the coupling unit structure model in the coupling layer of the present invention.

[0010] Figure 5 It is a schematic diagram of the layout of the radiation aperture and absorber layer in the radiation layer of the present invention.

[0011] Figure 6 It is a schematic diagram of a feeding network based on substrate integrated coaxial line (SICL) in the present invention.

[0012] Figure 7 It is the left-hand circular polarization pattern at 19 GHz in the present invention.

[0013] Figure 8 It is the left-hand circular polarization pattern at 25 GHz in the present invention.

[0014] Fig. 9 It is the left-hand circular polarization pattern at 31 GHz in the present invention.

[0015] Fig.10 It is a schematic diagram of the S parameter and axial ratio simulation results of the entire array antenna in the present invention.

[0016] In the figure: 1-radiation layer; 2-coupling layer; 3-SICL feeding network; 4-waveguide array antenna base; 5-2.92mm connector; 6-absorber layer; 7-circularly polarized radiation aperture; 8-absorber unit; 9-high frequency absorbing layer; 10-low frequency absorbing layer; 11-coupling layer unit (double-ridge waveguide to rectangular waveguide transition structure); 12-rectangular waveguide opening; 13-double-ridge waveguide; 14-radiation aperture and absorber layer layout; 15-SICL feeding network; 16-suspended microstrip line in the feed point network; 17-metal through hole. DETAILED DESCRIPTION

[0017] like Figure 1 As shown, an ultra-wideband circularly polarized millimeter wave communication array antenna based on a hollow waveguide includes a radiation layer 1, a coupling layer 2, a SICL (substrate integrated coaxial line) feeding network layer 3, a connector 5 and an absorber layer 6. The radiation layer 1, the coupling layer 2, and the SICL feeding network layer 3 are arranged in sequence from top to bottom. The bottom of the SICL feeding network layer 3 is a waveguide array antenna base 4. The SICL feeding network layer 3 includes a suspended microstrip line 16 and a metal through hole 17; the radiation layer includes a low-profile circularly polarized antenna subarray, that is, 16 radiation apertures 7; the absorber layer 6 includes three 1×10 absorber line arrays, that is, 30 absorber units 8.

[0018] Furthermore, the absorber unit 8 is composed of two layers of dielectric: a high-frequency absorbing layer 9 and a low-frequency absorbing layer 10. The dielectric plate used has a relative dielectric constant of 3.5 and a thickness of 0.1 mm. The two layers of dielectric plates are spaced 2 mm apart and have a size of 4.8×4.8 mm2. The pattern resistance is 270Ω.

[0019] Furthermore, the SICL feeding network layer suspends microstrip lines 16 and metal through holes 17, wherein the suspended microstrip line 16 is a 1-to-16 equal-amplitude and co-directional power divider for exciting each radiation aperture 7, and the microstrip line is surrounded by metal through holes 17 to prevent energy leakage.

[0020] Furthermore, the coupling layer 2 is a connection between the feeding network layer and the radiation layer. The coupling layer 2 is composed of a 4×4 arrangement of coupling apertures 11 , and the coupling apertures 11 and the radiation apertures 7 form a pair of first-order cascades.

[0021] Furthermore, the coupling aperture 11 transitions from the double-ridged waveguide to the rectangular waveguide 12, and transitions to the double-ridged waveguide 13 in the middle, forming a broadband match.

[0022] Furthermore, the connector 5 is a 2.92 mm connector, and the probe part is connected to the beginning of the microstrip line for exciting the entire array antenna.

[0023] The technical solution of the present invention is described in detail below in conjunction with embodiments.

[0024] Example

[0025] Combination Figure 1 The present invention is based on a broadband waveguide array antenna, which utilizes a broadband radiation structure and a broadband fully parallel feeding network cascaded to form a broadband array antenna. The impedance bandwidth and axial ratio bandwidth of the present invention are both greater than 49%. From 19 to 31 GHz, the input reflection coefficient is better than -15 dB, and the antenna efficiency exceeds 80% in the entire operating band. In the range of 19-31 GHz, the peak gain of circular polarization varies between 18.0 and 21.9 dBi. The present invention can realize the design of wide-band and wide-axial ratio of waveguide antennas, and can be suitable for millimeter wave communications.

[0026] Combination Figure 2 , is the ultra-wideband circularly polarized subarray in the present invention, which is improved from the rectangular waveguide wall. The notch on the wide side of the waveguide has a depth of 6mm and a side length of 3.5mm. Through the two notches, the metal wall part of the wide wall of the waveguide becomes a dipole structure under the action of the current J, generating an orthogonal field component with a phase difference of ±90, forming a circularly polarized response. The periodic arrangement uses a wavelength of 30GHz, which can avoid the appearance of grating lobes in the full band.

[0027] Combination Figure 3, is the unit structure model of the absorber layer in the invention, which is composed of the upper high-frequency absorbing layer 9 and the lower low-frequency absorbing layer 10. The unit structure period is 17mm, wherein the first layer is an open circular ring, the radius of the large circle is 1mm, the radius of the small circle is 0.5mm, and the hole width is 0.4mm; the second layer is a field shape, the side length of the square is 1.6mm, and the middle cross is a mutually perpendicular rectangle, 4mm long and 0.3mm wide. The dielectric plate used in the structure has a relative dielectric constant of 3.5, a thickness of 0.1mm, and the two layers of dielectric plates are 2mm apart, with a size of 4.8×4.8mm 2 The pattern resistance is 270Ω. Its function is to decouple between the radiation apertures and improve the overall axial ratio of the array antenna.

[0028] Combination Figure 4 , is the coupling unit structure model in the coupling layer of the invention. The transition structure from the double-ridge waveguide 13 to the rectangular waveguide 12 from bottom to top is intended to transition from the SICL feed line to the radiation structure, wherein a four-step ridge is used to meet the impedance bandwidth requirement.

[0029] Combination Figure 5 The layout 14 of the radiation aperture 7 and the absorber layer 6 in the radiation layer of the present invention is that the absorber layer 6 is placed in the gap between the radiation apertures 7. The absorber layer includes three 1×10 absorber line arrays. Such a layout can reduce the coupling effect of the antenna and improve the overall axial ratio of the antenna array to achieve an ultra-wideband circular polarization response.

[0030] Combination Figure 6 The present invention is based on a feed network of substrate integrated coaxial line (SICL). The SICL feed network layer 15 suspends microstrip lines 16 and metal through holes 17, wherein the suspended microstrip line is a 1-to-16 equal amplitude and co-directional power divider for exciting each radiation aperture; the microstrip line is surrounded by metal through holes to prevent energy leakage.

[0031] Combination Figure 7 , Figure 8 , Fig. 9 , are the radiation patterns of the antenna in the present invention. They are the radiation patterns of the left-hand circular polarization xoz-plane and yoz-plane at 19 GHz, 25 GHz and 31 GHz respectively. It can be seen that the radiation patterns are symmetrical under broadband response, and the radiation performance of the array antenna is good.

[0032] Combination Fig.10 , which are the S parameter and axial ratio simulation results of the array antenna as a whole. The reflection coefficient is better than -15dB at 19GHz-31GHz (phase bandwidth is 49%); the axial ratio is less than 3dB at 19GHz-31GHz (phase bandwidth is 49%). This shows that the array antenna has ultra-wideband impedance bandwidth and axial ratio bandwidth, and can work normally at 19GHz-31GHz (phase bandwidth is 49%).

Claims

1. An ultra-wideband circularly polarized millimeter wave communication array antenna based on a hollow waveguide, characterized in that: It includes a radiation layer (1), a coupling layer (2), a SICL feed network layer (3), a connector (5) and an absorber layer (6). The radiation layer (1), the coupling layer (2) and the SICL feed network layer (3) are arranged in sequence from top to bottom. The SICL feed network layer (3) includes a suspended microstrip line (16) and a metal through-hole (17). The radiation layer includes a circularly polarized antenna sub-array, that is, 16 radiation apertures (7). The absorber layer (6) includes three 1×10 absorber linear arrays, that is, 30 absorber units (8). The absorber unit (8) is composed of a high-frequency absorber layer (9) in the upper layer and a low-frequency absorber layer (10) in the lower layer. The high-frequency absorber layer (9) is an open circular ring shape, and the low-frequency absorber layer (10) is a cross shape.

2. The ultra-wideband circularly polarized millimeter wave communication array antenna based on hollow waveguide according to claim 1, characterized in that: The dielectric board used for the absorber unit (8) has a relative dielectric constant of 3.5, a thickness of 0.1 mm, a 2-mm interval between the two dielectric boards, a size of 4.8×4.8 mm2, and a pattern resistance value of 270 Ω for both.

3. The ultra-wideband circularly polarized millimeter wave communication array antenna based on hollow waveguide according to claim 1, characterized in that: The SICL feed network layer includes a suspended microstrip line (16) and a metal through-hole (17). The suspended microstrip line (16) is a 1-to-16 equal-amplitude and co-directional power divider, which is used to excite each radiation aperture (7). The microstrip line is surrounded by metal through-holes (17) to prevent energy leakage.

4. The ultra-wideband circularly polarized millimeter wave communication array antenna based on hollow waveguide according to claim 1, characterized in that: The coupling layer (2) is the connection between the feed network layer and the radiation layer. The coupling layer (2) is composed of a 4×4 arrangement of coupling apertures (11). The coupling aperture (11) and the radiation aperture (7) form a pair of first-level cascades.

5. The ultra-wideband circularly polarized millimeter wave communication array antenna based on hollow waveguide according to claim 4, characterized in that: The coupling aperture (11) transitions from a double-ridge waveguide to a rectangular waveguide (12), and is transitioned by a double-ridge waveguide (13) in the middle to form broadband matching.

6. The ultra-wideband circularly polarized millimeter wave communication array antenna based on hollow waveguide according to claim 1, characterized in that: The connector (5) is a 2.92-mm connector. The probe part is connected to the start of the microstrip line and is used to excite the entire array antenna.

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