A high-gain low-sidelobe conical beam antenna

Abstract

The present invention discloses a high-gain low-sidelobe conical beam antenna, which comprises a microstrip excitation unit and a conical opening horn. The center of the microstrip excitation unit is located on the central axis of the conical opening horn, and is connected to the annular column on the base of the conical opening horn through the bottom metal floor. The microstrip excitation unit comprises a radiation patch, a dielectric substrate and a metal floor, and the radiation patch is composed of three groups of radiation elements, which are a circular monopole radiation patch, six tree-like parasitic patches and annular radiation patches from the inside to the outside. The circular monopole radiation patch is fed by a coaxial probe to generate a conical beam, and the direction of the current on the surface of the patch is changed by six tree-like parasitic patches with choke slots to reduce the antenna side lobes. Finally, an additional resonance is introduced by loading an annular patch with a short-circuit pin to broaden the impedance bandwidth of the antenna.

Description

Technical Field

[0001] The invention belongs to antenna technology, and in particular relates to a high-gain low-sidelobe conical beam antenna. Background Art

[0002] Conical beam antennas have been widely used in ground satellite communication terminals, indoor WLAN micro base stations, and radio fuses. In the field of mobile satellite communications, antennas are often required to have longer transmission distances and higher communication quality, that is, the antennas need to have high gain. In the field of fuze guidance, high gain can enable the fuze system to detect targets farther away, and higher side lobes will make missiles easier to detect, so high gain and lower side lobes are required. Among the various existing conical beam antenna structures, high-gain conical beam antennas are often difficult to achieve and have higher antenna side lobes.

[0003] Reference 1 (RA Penchel, SR Zang, JRBergmann and F. JS Moreira. Design of Wideband Omnidirectional Dual-Reflector Antennas in Millimeter Waves [J]. IEEE Antennas and Wireless Propagation Letters, vol. 18, no. 5, pp. 906-910, May 2019.) designed a broadband dual-reflector conical beam antenna with a gain of up to 13 dBi, but the sidelobe balance is as high as -10 dB, and the antenna size is large due to the use of a dual reflector structure.

[0004] Reference 2 (P. Sanchez-Olivares, JL Masa-Campos, E. Garcia-Marin and D. Escalona-Moreno. High-Gain Conical-Beam Traveling-Wave Array Antenna Based on a Slotted Circular Waveguide at Ku-Band [J]. IEEE Transactions on Antennas and Propagation, vol. 68, no. 8, pp. 6435-6440, Aug. 2020.) designed a Ku-band high-gain conical beam array antenna with a maximum gain of 13.7 dBi and a sidelobe of -12 dB. The antenna adopts a multi-slot circular waveguide structure, which has disadvantages such as high sidelobes and complex processing. Summary of the invention

[0005] The object of the present invention is to provide a high-gain low-sidelobe tapered beam antenna.

[0006] The technical solution to realize the present invention is: a high-gain low-sidelobe conical beam antenna, characterized in that it includes a microstrip excitation unit and a conical opening horn, the microstrip excitation unit is located at the bottom of the conical opening horn, and the center of the microstrip excitation unit is located on the central axis of the conical opening horn, and the conical beam generated by the microstrip excitation unit is radiated outward through the conical opening horn mouth.

[0007] Preferably, the microstrip excitation unit includes a topmost radiation patch, a middle layer of a dielectric substrate and a bottom layer of a metal floor, wherein the radiation patch is composed of a circular monopole radiation patch, six tree-like parasitic patches and a ring-like radiation patch from the center of the circle radially outward, the circular monopole patch in the microstrip excitation unit generates a conical beam through coaxial probe feeding, the six tree-like parasitic patches are placed at equal angles along the edge of the circular monopole radiation patch, and each parasitic patch is provided with a choke slot dug to change the direction of current on the surface of the patch.

[0008] Preferably, a through hole with a diameter of the probe is dug out at the center of the dielectric substrate of the microstrip excitation unit, so that the probe can pass through the substrate to excite the top radiation patch.

[0009] Preferably, a circular through hole is dug out at the center of the metal floor of the microstrip excitation unit.

[0010] Preferably, the diameter of the circular through hole is 2 to 3 times the diameter of the probe.

[0011] Preferably, each tree-shaped parasitic patch is provided with five choke slots, one fan-shaped choke slot and two pairs of annular choke slots, and the central angle of the fan-shaped choke slot is β 2 , with a width of d 2 The two pairs of annular choke grooves are taken from two semicircular annular grooves respectively, and the inner and outer radii of one pair of annular choke grooves are R 6 ,R 7 , the central angles of the two annular choke slots are α 1 , α 2 The distance between the edge of the slot and the edge of the fan-shaped choke slot is d 3 The inner and outer radii of the other pair of annular choke slots are R 8 ,R 9 , the center angles of the two annular choke slots are θ 1 ,θ 2 The distance between the edge of the slot and the circular monopole patch is d 1 , α 1 =α 2 =80°, β 1 =50°, β 2 =35°,θ 1=80.05°,θ 2 =79.95°, d 1 =1.2mm,d 2 =0.9mm,d 3 =1.3mm, R 6 =0.8mm,R 7 =1.4mm.

[0012] Preferably, the inner radius R of the annular radiation patch is 2 =8mm, outer radius is R 1 =10.5mm, and the inner edge is loaded with a short-circuit pin with a diameter of d=0.4mm.

[0013] Preferably, the conical opening horn is a 360° rotationally symmetrical structure, and an annular column is loaded on the upper surface of the horn base for welding with the microstrip excitation unit.

[0014] Preferably, the inner diameter of the annular column is D 5 =17mm, outer diameter is D 4 =19mm, height H 3 =0.78mm, made of metal aluminum.

[0015] Preferably, the inner diameter of the cone-shaped opening horn at the opening is D 2 =43.56mm, outer diameter is D 1 =50mm, the diameter of the upper surface of the base is D 3 =22.4mm, the lower surface diameter is D 7 =26.4mm, height H from the upper surface of the base to the opening 2 =26mm, total height of cone-shaped opening speaker H 1 =30mm.

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

[0017] (1) The high-gain low-sidelobe conical beam antenna of the present invention has a simple structure and is easy to implement.

[0018] (2) The high-gain, low-sidelobe conical beam antenna of the present invention has the advantages of high gain and low sidelobe. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall front cross-section of the high-gain low-sidelobe conical beam antenna of the present invention.

[0020] Figure 2 It is a schematic top view of the overall cross-section of the high-gain low-sidelobe conical beam antenna of the present invention.

[0021] Figure 3It is a schematic diagram of a front cross-section of a microstrip excitation unit in a high-gain, low-sidelobe conical beam antenna of the present invention.

[0022] Figure 4 for Figure 3 A partial cross-sectional schematic diagram of .

[0023] Figure 5 It is a top view cross-sectional schematic diagram of a microstrip excitation unit in the high-gain low-sidelobe conical beam antenna of the present invention.

[0024] Figure 6 It is a bottom-up cross-sectional view of the microstrip excitation unit in the high-gain, low-sidelobe conical beam antenna of the present invention.

[0025] Figure 7 It is a side cross-sectional schematic diagram of a conical opening horn in the high-gain low-sidelobe conical beam antenna of the present invention.

[0026] Figure 8 It is a top view cross-sectional schematic diagram of the conical opening horn in the high-gain low-sidelobe conical beam antenna of the present invention.

[0027] Fig. 9 For along Figure 8 Schematic diagram of the cross-sectional structure along line AA.

[0028] Fig.10 This is a simulation diagram of the return loss of the antenna of an embodiment of the high-gain and low-sidelobe conical beam antenna of the present invention.

[0029] Fig.11 This is a far-field simulation radiation pattern of the high-gain low-sidelobe conical beam antenna of one embodiment of the present invention when phi=0° and phi=90° at 35GHz.

[0030] Fig.12 This is a far-field simulation radiation pattern of the maximum beam profile of the high-gain low-sidelobe conical beam antenna of one embodiment of the present invention at 35 GHz. DETAILED DESCRIPTION

[0031] The present invention is described in further detail below in conjunction with the accompanying drawings. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0032] Combination Figures 1-2A high-gain, low-sidelobe conical beam antenna is provided. The antenna consists of a microstrip excitation unit 2 and a conical opening horn 1. The center of the microstrip excitation unit is located on the central axis of the conical opening horn. The conical beam generated by the microstrip excitation unit is radiated outward through the conical opening horn mouth, thereby enhancing the directivity of the electromagnetic wave and achieving a high-gain effect.

[0033] In a further embodiment, in combination Figures 3 to 5 The top layer of the microstrip excitation unit is a radiation patch 21, the middle layer is a dielectric substrate 22, and the bottom layer is a metal floor 23, wherein the radiation patch 21 is composed of a circular monopole radiation patch 3, six tree-like parasitic patches 4 and annular radiation patch 5 from the center of the circle to the outside in a radial direction. The circular monopole patch 3 in the microstrip excitation unit generates a conical beam through coaxial probe feeding, and the six tree-like parasitic patches 4 are placed at equal angles along the edge of the circular monopole radiation patch 3. A choke groove is dug on each parasitic patch to change the direction of the current on the patch surface, thereby reducing the side lobes of the antenna. The six tree-like parasitic patches 4 are surrounded by an annular radiation patch 5 with a short-circuit pin, which introduces additional resonance and broadens the impedance bandwidth of the antenna. In addition, the loading of the short-circuit pin increases the radiation area during resonance, thereby improving the antenna gain.

[0034] In a further embodiment, a through hole with the diameter of the probe is dug out in the center of the dielectric substrate 22 of the middle layer of the microstrip excitation unit 2, so that the probe can pass through the substrate to excite the top radiation patch. A circular through hole is dug out in the center of the metal floor 23 of the microstrip excitation unit 2 to prevent a short circuit between the probe and the ground. For better matching, the diameter of the through hole is about 2 to 3 times the diameter of the probe.

[0035] In a further embodiment, in combination Figure 7 The conical opening horn 1 is a 360° rotationally symmetrical structure, and the upper surface of the horn base is loaded with an annular column 6 for welding with a low-profile conical beam antenna.

[0036] In a further embodiment, Figure 5 As shown, each tree-like parasitic patch has five choke slots, one fan-shaped choke slot and two pairs of annular choke slots. The central angle of the fan-shaped choke slot is β 2 , with a width of d 2 The two pairs of annular choke grooves are taken from two semicircular annular grooves respectively, and the inner and outer radii of one pair of annular choke grooves are R 6 ,R 7 , the center angles of the two annular choke slots are α 1 , α 2 The distance between the edge of the slot and the edge of the fan-shaped choke slot is d 3 The inner and outer radii of the other pair of annular choke slots are R 8 ,R 9 , the center angles of the two annular choke slots are θ1 ,θ 2 The distance between the edge of the slot and the circular monopole patch is d 1 The cross-section of a conical opening horn is shown below: Fig. 9 As shown, the overall height of the conical opening horn is H 1 , the opening height is H 2 , the height of the annular column is H 3 .

[0037] In the above technical solution, the part of achieving high gain of the antenna is: the size of the aperture of the conical opening horn. For ordinary horn antennas, the larger the aperture, the higher the antenna gain, but the beam width and antenna side lobes must often be considered at the same time. In this antenna, a wavelength of about 5 times the center frequency is selected. In addition, the short-circuit pins on the annular radiation patch also affect the antenna gain. If the distance between adjacent short-circuit pins is too large, mutual coupling will occur, which is generally about 0.05 wavelengths. The present invention takes 0.06 wavelengths.

[0038] In the above scheme, the low sidelobe part of the antenna is achieved by: the angle and width of the slot on the parasitic patch, and the height of the annular column in the conical opening horn; whether the parasitic patch is slotted and the direction of the slot have a greater impact on the antenna sidelobe, and the direction of the slot should be perpendicular to the current flow direction of the circular monopole patch surface. The present invention adopts a coaxial probe feeding method to provide a high-gain, low-sidelobe conical beam antenna with simple feeding.

[0039] The working process of the present invention is as follows: the circular monopole radiating patch in the microstrip excitation unit is fed by a coaxial probe to generate a conical beam, and the direction of the current on the patch surface is changed by six tree-like parasitic patches with choke slots to reduce the antenna side lobe, and finally an annular radiating patch with a short-circuit pin is loaded to introduce additional resonance to broaden the impedance bandwidth of the antenna. 01 Mold and TM 01 The mode radiates outward along the horn mouth, which enhances the directionality of the electromagnetic wave and achieves the effect of increasing the antenna gain.

[0040] The present invention is further described in detail below in conjunction with specific embodiments.

[0041] Example 1

[0042] A high-gain, low-sidelobe conical beam antenna of this embodiment is composed of a microstrip excitation unit and a conical opening horn. The center of the microstrip excitation unit is located on the central axis of the conical opening horn and is connected to the annular column on the base of the conical opening horn through a bottom metal floor.

[0043] like Figures 3 to 5As shown, the thickness of the radiation patch and the metal floor is th = 0.018mm, the dielectric substrate is RogersRO4350 plate, its thickness subH = 0.508mm, and the radius R 1 =10.5mm, dig out the diameter d in the middle 4 =0.75mm through hole is used for probe feeding.

[0044] The radiation patch includes a circular monopole radiation patch 3, six tree-like parasitic patches 4, and an annular radiation patch 5. The radius of the circular monopole radiation patch is R5=1.78 mm, and the tree-like parasitic patches are placed in sequence along the edge of the circular monopole patch, with an outer circle radius of R 3 =7mm, by digging grooves to change the current flow direction in the patch to obtain lower side lobes, such as Figure 5 As shown, the size of the slots on the six parasitic patches is α 1 =α 2 =80°, β 1 =50°, β 2 =35°,θ 1 =80.05°,θ 2 =79.95°, d 1 =1.2mm,d 2 =0.9mm,d 3 =1.3mm. R 6 =0.8mm,R 7 =1.4mm,R 8 =1.2mm,R 9 =1.8mm, inner radius R of the annular radiation patch 2 =8mm, outer radius is R 1 =10.5mm, the inner edge is loaded with short-circuit pins with a diameter of d = 0.4mm (90 in total), and the middle of the radiation patch is dug out d 4 =0.75mm through hole is used for probe feeding.

[0045] The diameter of the metal floor is R 1 =10.5mm, dig out the diameter d in the middle 5 =1.8mm through hole.

[0046] like Fig. 9 As shown, the inner diameter of the conical opening horn is D 2 =43.56mm, outer diameter is D 1 =50mm, the diameter of the upper surface of the base is D 3 =22.4mm, the lower surface diameter is D 7 =26.4mm, height H from the upper surface of the base to the opening 2 =26mm, total height of cone-shaped opening speaker H 1=30mm. The inner diameter of the annular column on the upper surface of the base is D 5 =17mm, outer diameter is D 4 =19mm, height H 3 =0.78mm, made of metal aluminum.

[0047] The overall structure of the antenna is simulated and optimized in the electromagnetic simulation software AnsysHFSS, and the simulation results of the high-gain and low-sidelobe conical beam antenna are obtained.

[0048] Fig.10 The figure shows the return loss of the high-gain low-sidelobe conical beam antenna of this embodiment. It can be seen from the figure that in the frequency band of 34.59 GHz to 36.62 GHz, the return loss is less than -10 dB.

[0049] Fig.11 The far-field radiation pattern of the high-gain low-sidelobe conical beam antenna of this embodiment at 35GHz, phi = 0° and phi = 90° is shown. It can be seen from the figure that at 35GHz, the maximum pointing angle of the antenna is 10°, the gain is 14.7dBi, and the SLL is -23.6dB.

[0050] Fig.12 The far-field pattern of the high-gain low-sidelobe conical beam antenna at 35GHz is shown in the figure. It can be seen from the figure that the ripple of the maximum beam profile is 0.156dB, and the roundness is good.

Claims

1. A high-gain low-sidelobe conical beam antenna, characterized in that: It includes a microstrip excitation unit and a conical opening horn, wherein the microstrip excitation unit is located at the bottom of the conical opening horn, and the center of the microstrip excitation unit is located on the central axis of the conical opening horn, and the conical beam generated by the microstrip excitation unit radiates outward through the conical opening horn mouth, and the microstrip excitation unit includes a topmost radiation patch, a middle layer of a dielectric substrate, and a bottom layer of a metal floor, wherein the radiation patch is composed of a circular monopole radiation patch, six tree-like parasitic patches, and annular radiation patches from the center of the circle radially outward, the circular monopole patch in the microstrip excitation unit generates a conical beam through coaxial probe feeding, the six tree-like parasitic patches are placed at equal angles along the edge of the circular monopole radiation patch, and each parasitic patch is provided with a choke slot to change the current direction on the patch surface; each tree-like parasitic patch is provided with 5 choke slots, a fan-shaped choke slot and two pairs of annular choke slots, and the fan-shaped choke slots are provided with a fan-shaped choke slot and a fan-shaped choke slot. The central angle of the fan-shaped choke slot is β2, and the width is d2. The two pairs of annular choke slots are taken from two semicircular annular slots respectively. The inner and outer radii of one pair of annular choke slots are R6 and R7 respectively, and the central angles of the two annular choke slots are α1 and α2 respectively. The distance between the edge of the slot and the edge of the fan-shaped choke slot is d3. The inner and outer radii of the other pair of annular choke slots are R8 and R9 respectively, and the central angles of the two annular choke slots are θ1 and θ2 respectively. The distance between the edge of the slot and the circular monopole patch is d1, α1=α2=80°, β2=50°, θ1=80.05°, θ2=79.95°, d1=1.2mm, d2=0.9mm, d3=1.3mm, R6=0.8mm, R7=1.4mm. A through hole of the probe diameter is dug in the center of the dielectric substrate of the microstrip excitation unit to allow the probe to pass through the substrate to excite the top-layer radiation patch.

2. The high-gain low sidelobe conical beam antenna according to claim 1, characterized in that: A circular through hole is dug out at the center of the metal floor of the microstrip excitation unit.

3. The high-gain low sidelobe conical beam antenna according to claim 2, characterized in that: The diameter of the circular through hole is 2 to 3 times the diameter of the probe.

4. The high-gain low sidelobe conical beam antenna according to claim 1, characterized in that: The inner radius of the annular radiation patch is R2 = 8 mm, the outer radius is R1 = 10.5 mm, and the inner edge is loaded with a short-circuit pin with a diameter of d = 0.4 mm.

5. The high-gain low sidelobe conical beam antenna according to claim 1, characterized in that: The conical opening horn is a 360° rotationally symmetrical structure, and an annular column is loaded on the upper surface of the horn base for welding with the microstrip excitation unit.

6. The high-gain low sidelobe conical beam antenna according to claim 4, characterized in that: The inner diameter of the annular column is D5=17mm, the outer diameter is D4=19mm, the height is H3=0.78m, and the material is metal aluminum.

7. The high-gain low sidelobe conical beam antenna according to claim 1, characterized in that: The inner diameter of the conical opening horn at the opening is D2=43.56m, the outer diameter is D1=50m, the upper surface diameter of the base is D3=22.4mm, the lower surface diameter is D7=26.4mm, the height from the upper surface of the base to the opening is H2=26mm, and the total height of the conical opening horn is H1=30mm.

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