A substrate integrated waveguide based wideband circularly polarized millimeter wave antenna

Abstract

A kind of wideband circularly polarized millimeter wave antenna based on substrate integrated waveguide, including open substrate integrated waveguide for exciting vertical polarization wave, open substrate integrated waveguide is loaded with antipode gradual groove slot structure and antipode groove, antipode gradual groove slot structure is used to provide horizontal polarization wave, 2xM is provided with truncated slot, and truncated slot is used to regulate vertical polarization component of circularly polarized wave;Antipode groove is loaded in the open end of open substrate integrated waveguide, for exciting new circularly polarized resonance point.The present application mainly solves the problem of narrow working bandwidth of existing circularly polarized antenna based on substrate integrated waveguide, overcomes the limitations of existing such antenna application, and the designed antenna has good wideband circularly polarized characteristics in millimeter wave frequency band.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic field and microwave technology, and specifically relates to a broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide, which can be used in high-speed, high-capacity and low-latency circularly polarized communication scenarios. Background Technology

[0002] In recent years, with the rapid development of wireless communication technology and the increasing number of electronic devices, the low-frequency spectrum has become extremely crowded, drawing increasing attention to millimeter-wave technology. Substrate integrated waveguides, with their advantages of low profile, low radiation interference, high quality factor, high power capacity, and ease of integration, have become strong competitors in millimeter-wave wireless communication systems. Circularly polarized antennas offer advantages such as resistance to rain and fog interference, suppression of multipath reflections, and avoidance of polarization mismatch. Broadband antennas, with their high bandwidth, high transmission rate, large capacity, and low latency, have been widely used in satellite communication and radar systems. Therefore, research on broadband circularly polarized millimeter waves based on substrate integrated waveguides is of great significance. However, the inherent characteristics of the mode propagation of substrate integrated waveguides and their low profile result in narrow bandwidth for circularly polarized antennas in existing research, hindering the development of this type of antenna. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention aims to provide a broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide, primarily addressing the problem of narrow operating bandwidth in existing circularly polarized antennas based on substrate integrated waveguides, and overcoming the limitations of such antenna applications. The designed antenna exhibits excellent broadband circular polarization characteristics in the millimeter-wave band.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide includes an open substrate integrated waveguide for exciting vertically polarized waves. The open substrate integrated waveguide is loaded with a heel-gradient slot structure and a heel-groove. The heel-gradient slot structure is used to provide horizontally polarized waves and has a total of 2×M truncated slots. The truncated slots are used to control the vertical polarization component of the circularly polarized waves. The heel-groove is loaded at the open end of the open substrate integrated waveguide to excite new circularly polarized resonant points.

[0006] In one embodiment, the open substrate integrated waveguide includes a dielectric substrate with metal vias, the front and back patterns of the dielectric substrate being heel-to-heel, wherein a first metal ground plane and a first gradient slot structure are printed on the front side, and a second metal ground plane and a second gradient slot structure are printed on the back side; the first gradient slot structure includes a first gradient metal layer and M first truncated slots etched on the first gradient metal layer; the second gradient slot structure includes a second gradient metal layer and M second truncated slots etched on the second gradient metal layer; the first gradient metal layer is in contact with the first metal ground plane, and the second gradient metal layer is in contact with the second metal ground plane; the first gradient slot structure and the second gradient slot structure form the heel-to-heel gradient slot structure, and the M first truncated slots and the M second truncated slots form the 2×M truncated slots.

[0007] In one embodiment, in the first cut-off slit and / or the second cut-off slit, the length of each slit gradually increases or decreases in sequence, the width gradually decreases or increases in sequence, and the distance between the central axes of adjacent slits gradually decreases or increases in sequence.

[0008] In one embodiment, both the first truncated slot and the second truncated slot satisfy the following formula:

[0009] 0.25λ1vL<0.25λ2

[0010] In the formula, λ1 is the wavelength of the medium corresponding to the highest operating frequency of the antenna, λ2 is the wavelength of the medium corresponding to the lowest operating frequency of the antenna, and L is the distance between the central axes of adjacent slots in the M first truncated slots or M second truncated slots.

[0011] In one embodiment, the metal through holes are arranged in three rows, each metal through hole connecting the first metal plate and the second metal plate, and the center line connecting the three rows of metal through holes forms a U-shape, with the U-shaped opening facing the heel-to-heel gradient slot structure; a first circular slot is etched on the first metal plate, and a second circular slot is etched on the second metal plate.

[0012] In one embodiment, the three columns of metal through holes satisfy the following formula:

[0013] D < P < 2D

[0014] D / λ g <0.2

[0015] 0.05 < P / λ c <0.25

[0016] In the formula, D is the diameter of the metal through hole, P is the distance between the centers of adjacent metal through holes in the same column, and λ is the diameter of the through hole. gIt is the waveguide wavelength of the open substrate integrated waveguide, λ. c It is the cutoff wavelength of an open substrate integrated waveguide.

[0017] In one embodiment, the dielectric substrate is a cuboid, and both the first and second metal ground plates are rectangular, with the same width as the dielectric substrate and a length less than the length of the dielectric substrate. Both the first and second gradient metal layers have a three-sided structure. In the first gradient metal layer, the first side is connected to a portion of the wide side of the first metal ground plate, the second side is flush with a longitudinal edge of the dielectric substrate, and the third side is a gradient edge, with the distance between the gradient edge and the second side gradually increasing towards the first metal ground plate. The longitudinal direction of the first truncated slot is parallel to the direction of the first side. Similarly, in the second gradient metal layer, the first side is connected to a portion of the wide side of the second metal ground plate, the second side is flush with a longitudinal edge of the dielectric substrate, and the third side is a gradient edge, with the distance between the gradient edge and the second side gradually increasing towards the second metal ground plate. The longitudinal direction of the second truncated slot is parallel to the direction of the first side.

[0018] In one embodiment, the gradient edge is a straight line, a broken line, or an arc.

[0019] In one embodiment, from the direction away from the first metal floor to the direction closer to the first metal floor, the length of the M first truncated slots gradually increases, the width gradually decreases, and the distance between the central axes of adjacent slots gradually decreases; from the direction away from the second metal floor to the direction closer to the second metal floor, the length of the M second truncated slots gradually increases, the width gradually decreases, and the distance between the central axes of adjacent slots gradually decreases.

[0020] In one embodiment, a first groove is etched on one side of the first metal floor, and a second groove is etched on one side of the second metal floor. Both the first groove and the second groove are rectangular grooves, forming the heel-to-heel groove.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] First, the present invention uses an open substrate integrated waveguide to provide vertically polarized waves. When the electromagnetic wave reaches the connection between the substrate integrated waveguide and the heel-gradient slot structure, part of the vertically polarized wave is converted into a horizontally polarized wave and propagates along the slot line. The superposition of the two orthogonal polarized waves excites the first circularly polarized resonant point.

[0023] Second, the present invention uses an open substrate integrated waveguide to provide a vertically polarized wave. Heel grooves are etched at the open end of the substrate integrated waveguide to generate an equivalent electric field in the horizontal direction to excite the horizontally polarized wave. The superposition of two orthogonal polarized waves excites the second circularly polarized resonant point.

[0024] Third, the present invention employs a method of etching truncated slots on a heel-gradient groove structure to excite vertically polarized waves, thereby controlling the vertically polarized wave component of the circularly polarized wave and thus obtaining broadband circularly polarized characteristics. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide according to the present invention.

[0026] Figure 2 This is a schematic diagram of the structure of the broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide according to the present invention.

[0027] Figure 3 These are the front view, rear view, and side view of the broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide according to the present invention.

[0028] Figure 4 This is a reflection coefficient curve of an embodiment of the present invention in the frequency band range of 20.0 to 40.0 GHz.

[0029] Figure 5 This is an embodiment of the invention in the azimuth angle. Axis ratio curve in the frequency band of 20.0–40.0 GHz when the pitch angle θ = 0°.

[0030] Figure 6 This is an embodiment of the invention in the azimuth angle. Left-hand circular polarization gain curve in the frequency band of 20.0–40.0 GHz when the pitch angle θ = 0°.

[0031] Figure 7 This is an embodiment of the invention in the azimuth angle. Normalized radiation pattern at 27.0 GHz with elevation angles θ = 0° to 360°.

[0032] Figure 8 This is an embodiment of the invention in the azimuth angle. Normalized radiation pattern at 27.0 GHz with elevation angles θ = 0° to 360°.

[0033] Figure 9 This is an embodiment of the invention in the azimuth angle. Normalized radiation pattern at 32.5 GHz when the elevation angle θ = 0° to 360°.

[0034] Figure 10 This is an embodiment of the invention in the azimuth angle. Normalized radiation pattern at 32.5 GHz when the elevation angle θ = 0° to 360°.

[0035] Figure 11 This is an embodiment of the invention in the azimuth angle. Normalized radiation pattern at 38.0 GHz when the elevation angle θ = 0° to 360°.

[0036] Figure 12 This is an embodiment of the invention in the azimuth angle. Normalized radiation pattern at 38.0 GHz when the elevation angle θ = 0° to 360°. Detailed Implementation

[0037] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples.

[0038] like Figure 1 As shown, this invention relates to a broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide, comprising an open substrate integrated waveguide 1, and a heel-mounted tapered slot structure 2 and a heel-mounted groove 3 loaded on the open substrate integrated waveguide 1. The open substrate integrated waveguide 1 is used to excite vertically polarized waves, the heel-mounted tapered slot structure 2 is used to provide horizontally polarized waves, and the heel-mounted groove 3 is used to excite a new circularly polarized resonant point. When the electromagnetic wave reaches the connection between the open substrate integrated waveguide 1 and the heel-mounted tapered slot structure 2, part of the vertically polarized wave is converted into a horizontally polarized wave and propagates along the tapered edge of the heel-mounted tapered slot structure 2. The superposition of the two orthogonally polarized waves excites the first circularly polarized resonant point.

[0039] The heel groove 3 is etched and applied to the open end of the open substrate integrated waveguide 1 to generate an equivalent electric field in the horizontal direction to excite the horizontally polarized wave. The superposition of the two orthogonal polarized waves excites the second circularly polarized resonant point.

[0040] In this invention, a total of 2×M truncated slots 4 are etched on the heel-gradient groove structure 2. The truncated slots 4 are used to control the vertical polarization component of the circularly polarized wave. The vertically polarized wave can be excited through the truncated slots 4, thereby realizing the control of the vertical polarization component of the circularly polarized wave and obtaining good broadband circular polarization characteristics. Experiments have shown that its working bandwidth exceeds 55%.

[0041] In one specific embodiment of the present invention, reference is made to... Figure 1 and Figure 2 The open-substrate integrated waveguide 1 includes a dielectric substrate 11, the front and back patterns of which are heel-to-heel, and a metal via 12 is formed on the dielectric substrate 11. The dielectric substrate 11 of the present invention can take any suitable shape. The present invention describes it as a cuboid, and the principle of other shapes is similar.

[0042] For ease of description, this invention defines the length direction of the dielectric substrate 11 as the z-direction, the width direction as the y-direction, and the thickness direction as the x-direction, as follows: Figure 1 and Figure 2As shown, the "front" and "back" of this invention are relative to the x-direction. Obviously, the metal through hole 12 is opened along the x-direction, connecting the "front" and "back".

[0043] In this embodiment, a first metal ground plane 131 and a first gradient slot structure 141 are printed on the front side of the dielectric substrate 11, and correspondingly, a second metal ground plane 132 and a second gradient slot structure 142 are printed on the back side. The first metal ground plane 131 and the second metal ground plane 132 are in a heel-to-heel relationship, and the first gradient slot structure 141 and the second gradient slot structure 142 are in a heel-to-heel relationship.

[0044] The first gradient slot structure 141 includes a first gradient metal layer 181, on which M first truncated slots 171 are etched. The second gradient slot structure 142 includes a second gradient metal layer 182, on which M second truncated slots 172 are etched. In this invention, each first truncated slot 171 is an opening etched on the first gradient metal layer 181, with its length direction in the y-direction. Similarly, each second truncated slot 172 is a slot with openings at both ends etched on the second gradient metal layer 182, with its length direction in the y-direction.

[0045] The first gradient metal layer 181 is connected to the first metal floor 131, and the second gradient metal layer 182 is connected to the second metal floor 132; the first gradient slot structure 141 and the second gradient slot structure 142 constitute the heel-to-heel gradient slot structure 2, and the M first truncated slots 171 and the M second truncated slots 172 constitute the 2×M truncated slots 4.

[0046] The "gradient" in this invention mainly includes the gradual change of the cut-off gaps 4. Specifically, in the first cut-off gap 171 and / or the second cut-off gap 172, the length of each gap gradually increases or decreases in sequence, the width gradually decreases or increases in sequence, and the distance between the central axes of adjacent gaps gradually decreases or increases in sequence. In this invention, "sequence" refers to the direction from away from the first metal floor 131 or the second metal floor 132 towards the first metal floor 131 or the second metal floor 132, or its "reverse direction," that is, the z-direction defined in this invention, or the corresponding -z-direction.

[0047] Different frequencies of electromagnetic waves correspond to different electrical lengths. The width of the truncated slot is positively correlated with the amount of electromagnetic wave radiation, and the distance between the central axes of adjacent slots is related to the phase of the radiated electromagnetic wave. By setting this gradually changing truncated slot, the amplitude and phase of the radiated electromagnetic wave can be gradually altered, allowing electromagnetic waves of different frequencies to superimpose in phase. This enables the control of the circular polarization performance of the millimeter-wave antenna at multiple frequency points, thereby achieving good circular polarization radiation characteristics over a wider frequency range and thus broadening the operating bandwidth of the circularly polarized millimeter-wave antenna.

[0048] Furthermore, in one embodiment of the present invention, both the first truncated slot 171 and the second truncated slot 172 satisfy the following formula:

[0049] 0.25λ ε1 <L<0.25λ ε2

[0050] In the formula, λ1 is the medium wavelength corresponding to the highest operating frequency of the antenna, λ2 is the medium wavelength corresponding to the lowest operating frequency of the antenna, and L is the distance between the central axes of adjacent slots in the M first truncated slots 171 or the M second truncated slots 172.

[0051] The distance between the central axes of adjacent slots is limited to a certain range using the formula defined in this embodiment. This ensures that when electromagnetic waves within the antenna's operating frequency band radiate outwards through the truncated slots, the spacing is 1 / 4 wavelength, thereby achieving in-phase superposition of vertically polarized waves and ultimately controlling the circular polarization performance of the millimeter-wave antenna.

[0052] The metal vias 12 of this invention are an inherent feature of the substrate integrated waveguide, forming a semi-closed structure with the first metal ground plane 131 and the second metal ground plane 132 in the dielectric substrate 11 for electromagnetic wave transmission. In one embodiment, they are arranged in three rows, with each metal via 12 connecting the first metal ground plane 131 and the second metal ground plane 132. The center line connecting the three rows of metal vias 12 forms a U-shape, with the U-shaped opening facing the location of the heel-gradient slot structure 2, that is, towards the open end of the open substrate integrated waveguide 1. That is, in this embodiment, two rows of metal vias 12 are arranged along the z-direction, and the other row of metal vias 12 is arranged along the y-direction. Generally, these three rows of metal vias 12 can be arranged close to the edge of the metal ground plane. Further, the three rows of metal vias 12 satisfy the following formula:

[0053] D < P < 2D

[0054] D / λ g <0.2

[0055] 0.05 < P / λ c <0.25

[0056] In the formula, D is the diameter of the metal through hole 12, P is the distance between the centers of adjacent metal through holes in the same column, and λ g It is the waveguide wavelength λ of open substrate integrated waveguide 1. c It is the cutoff wavelength of open substrate integrated waveguide 1.

[0057] The open substrate integrated waveguide 1 is constructed using the formula defined in this embodiment. Its functions are twofold: first, to ensure that electromagnetic waves propagate within the open substrate integrated waveguide 1 without leakage; and second, to ensure the mechanical strength of the antenna, preventing bending or deformation.

[0058] In one embodiment of the present invention, a first circular groove 151 is etched on a first metal plate 131, and a second circular groove 152 is etched on a second metal plate 132.

[0059] The first circular slot 151 serves as a conversion structure between the substrate integrated waveguide and the coaxial line, transforming the substrate integrated waveguide feeding structure into a commercially available and mature coaxial line feeding structure. The second circular slot 152 optimizes the impedance matching between the substrate integrated waveguide and the coaxial line, thereby achieving good transmission performance. In this embodiment, the first circular slot 151 and the second circular slot 152 have the same dimensions, but they may differ in other embodiments.

[0060] In one embodiment of the present invention, both the first metal ground plane 131 and the second metal ground plane 132 are rectangular, with a width equal to the width of the dielectric substrate 11 and a length less than the length of the dielectric substrate 11. Both the first gradient metal layer 181 and the second gradient metal layer 182 are three-sided structures. Wherein:

[0061] The first edge of the first gradient metal layer 181 is a y-axis edge, which is connected to a portion of the wide edge of the first metal floor 131, i.e., the y-axis edge. The second edge is a z-axis edge, which is flush with the edge of a length direction edge of the dielectric substrate 11, i.e., the z-axis edge. The third edge is a gradient edge, which gradually increases in distance from the gradient edge of the first gradient metal layer 181 to its second edge in the direction closer to the first metal floor 131. The length direction of the first truncated gap 171 is also y-axis.

[0062] The first side of the second gradient metal layer 182 is a y-direction side, which is connected to a part of the wide side of the second metal floor 132, i.e., the y-direction side. The second side is a z-direction side, which is flush with the edge of a length direction side of the dielectric substrate 11, i.e., the z-direction side. The third side is a gradient side, which gradually increases in distance from the gradient side of the second gradient metal layer 182 to the second side in the direction closer to the second metal floor 132. The length direction of the second truncated gap 172 is also y-direction.

[0063] On the side where the first metal floor 131 connects to the first edge of the first gradient metal layer 181, the other part of the first groove 161 is etched. On the side where the second metal floor 132 connects to the first edge of the second gradient metal layer 182, the other part of the second groove 162 is etched. Both the first groove 161 and the second groove 162 are rectangular grooves, and the two form a heel-to-heel groove 3.

[0064] In this invention, the gradient edges of the first gradient metal layer 181 and the second gradient metal layer 182 can be straight, polygonal, or arc-shaped. Straight, polygonal, or arc-shaped are all common forms of gradient slot structures, which manifest as different shapes of the bevels in terms of structure, and will result in slight differences in antenna operating bandwidth, gain, and radiation pattern in terms of antenna performance.

[0065] Taking the straight line type as an example, the first gradient metal layer 181 and the second gradient metal layer 182 are right-angled triangles. From the direction away from the first metal floor 131 to the direction closer to the first metal floor 131, the length of the M first truncated gaps 171 gradually increases and the width gradually decreases, and the distance between the central axes of adjacent gaps shows a decreasing trend. From the direction away from the second metal floor 132 to the direction closer to the second metal floor 132, the length of the M second truncated gaps 172 gradually increases and the width gradually decreases, and the distance between the central axes of adjacent gaps shows a decreasing trend.

[0066] Different frequencies of electromagnetic waves correspond to different electrical lengths. The width of the truncated slot is positively correlated with the amount of electromagnetic wave radiation, and the distance between the central axes of adjacent slots is related to the phase of the radiated electromagnetic wave. By setting this gradually changing truncated slot, the amplitude and phase of the radiated electromagnetic wave can be gradually altered, allowing electromagnetic waves of different frequencies to superimpose in phase. This enables the control of the circular polarization performance of the millimeter-wave antenna at multiple frequency points, thereby achieving good circular polarization radiation characteristics over a wider frequency range and thus broadening the operating bandwidth of the circularly polarized millimeter-wave antenna.

[0067] In one specific embodiment of the present invention, reference is made to... Figure 1 , Figure 2 and Figure 3 The number of truncated slots 4 is M = 5. The dielectric substrate 11 has a cuboid structure, and the relative permittivity and loss tangent of the material used are both 3.55 and 0.0027. The height L of the dielectric substrate 11 is... sub It is 15.68mm in diameter and has a width of W. sub It is 5.95mm thick, with a thickness of H. sub The radius R1 of the first circular groove 151 and the second circular groove 152 is 0.62 mm, and the distance L between them and the single row of metal through holes distributed along the y direction is 1.524 mm. pThe diameter is 1.47mm; both the first groove 161 and the second groove 162 are rectangular structures with a height L. n It is 0.65mm, and the width is W. n The height is 1.36mm; both the first gradient slot structure 141 and the second gradient slot structure 142 are triangular structures with a height L. a It is 6.8mm thick and has a width of W. a It is 2.55mm.

[0068] In the three rows of metal through holes 12, the diameter D of the two rows of metal through holes distributed along the z-direction is 0.5 mm, the distance P between the centers of adjacent metal through holes in the same row is 0.8 mm, and the distance W between the two rows of metal through holes is... siw The diameter D2 of the single-row metal through holes distributed along the y-direction is 0.4mm, and the distance P2 between the centers of adjacent metal through holes in the same row is 0.63mm; the height L of metal plate 13 and metal plate 131 is 5mm. siw It is 8.8mm in diameter and has a width of W. sub It is 5.95mm.

[0069] In the first truncated slot 171 and the second truncated slot 172, the distance L1 between the open end of the substrate integrated waveguide and the central axis of the first slot is 1.25 mm, and the width S1 of the first slot is 0.05 mm. The distance L2 between the second slot and the central axis of the first slot is 1.14 mm, and the width S2 of the second slot is 0.06 mm. The distance L3 between the third slot and the central axis of the second slot is 0.94 mm, and the width S3 of the third slot is 0.16 mm. The distance L4 between the fourth slot and the central axis of the third slot is 0.8 mm, and the width S4 of the fourth slot is 0.2 mm. The distance L5 between the fifth slot and the central axis of the fourth slot is 0.65 mm, and the width S5 of the fifth slot is 0.25 mm.

[0070] The effects of this invention can be further illustrated by the following simulations:

[0071] I. Simulation Software:

[0072] Commercial Ansoft HFSS 19.0 software.

[0073] II. Simulation Content:

[0074] Simulation 1 simulated the reflection coefficient of the embodiment of the present invention in the frequency band range of 20.0–40.0 GHz. The simulation results are as follows. Figure 4 As shown. By Figure 4 It can be seen that in the frequency range of 21.4 to 40.0 GHz, the reflection coefficient of the embodiment is less than -10 dB, and the impedance bandwidth of the embodiment is 60.6%.

[0075] Simulation 2, when the azimuth angle With a pitch angle θ = 0°, the axial ratio of the embodiment of the present invention was simulated in the frequency band range of 20.0–40.0 GHz. The simulation results are as follows: Figure 5 As shown. By Figure 5 It can be seen that in the frequency band range of 22.7 to 40.0 GHz, the axial ratio of the embodiment is less than 3 dB, and the axial ratio bandwidth is 55.2%.

[0076] Simulation 3, when the azimuth angle With an elevation angle θ = 0°, the left-hand circular polarization gain of the embodiment of the present invention in the frequency band range of 20.0–40.0 GHz was simulated, and the simulation results are as follows: Figure 6 As shown. By Figure 6 It can be seen that within the frequency band range of 22.7–40.0 GHz, the gain of the embodiment is between 4.0 and 9.8 dBic. The embodiment has a maximum gain at 40.0 GHz, which is 9.8 dBic.

[0077] Simulation 4, when the azimuth angle The normalized radiation pattern at 27.0 GHz of the embodiment of the present invention was simulated with an elevation angle θ = 0° to 360°. The simulation results are as follows: Figure 7 As shown. The solid line represents the normalized radiation pattern of the left-hand circularly polarized embodiment, and the dashed line represents the normalized radiation pattern of the right-hand circularly polarized embodiment. Figure 7 It can be seen that at 27.0 GHz, the maximum gain of the embodiment is in the θ = 0° direction.

[0078] Simulation 5, when the azimuth angle The normalized radiation pattern at 27.0 GHz of the embodiment of the present invention was simulated with an elevation angle θ = 0° to 360°. The simulation results are as follows: Figure 8 As shown. The solid line represents the normalized radiation pattern of the left-hand circularly polarized embodiment, and the dashed line represents the normalized radiation pattern of the right-hand circularly polarized embodiment. Figure 8 It can be seen that at 27.0 GHz, the maximum gain of the embodiment is in the θ = 0° direction.

[0079] Simulation 6, when the azimuth angle The normalized radiation pattern at 32.5 GHz of the embodiment of the present invention was simulated with an elevation angle θ = 0° to 360°. The simulation results are as follows: Figure 9 As shown. The solid line represents the normalized radiation pattern of the left-hand circularly polarized embodiment, and the dashed line represents the normalized radiation pattern of the right-hand circularly polarized embodiment. Figure 9 It can be seen that at 32.5 GHz, the maximum gain of the embodiment is in the θ = 0° direction.

[0080] Simulation 7, when the azimuth angle The normalized radiation pattern at 32.5 GHz of the embodiment of the present invention was simulated with an elevation angle θ = 0° to 360°. The simulation results are as follows: Figure 10 As shown. The solid line represents the normalized radiation pattern of the left-hand circularly polarized embodiment, and the dashed line represents the normalized radiation pattern of the right-hand circularly polarized embodiment. Figure 10 It can be seen that at 32.5 GHz, the maximum gain of the embodiment is in the θ = 0° direction.

[0081] Simulation 8, when the azimuth angle The normalized radiation pattern at 38.0 GHz of the embodiment of the present invention was simulated with an elevation angle θ = 0° to 360°. The simulation results are as follows: Figure 11 As shown. The solid line represents the normalized radiation pattern of the left-hand circularly polarized embodiment, and the dashed line represents the normalized radiation pattern of the right-hand circularly polarized embodiment. Figure 11 It can be seen that at 38.0 GHz, the maximum gain of the embodiment is in the θ = 0° direction.

[0082] Simulation 9, when the azimuth angle The normalized radiation pattern at 38.0 GHz of the embodiment of the present invention was simulated with an elevation angle θ = 0° to 360°. The simulation results are as follows: Figure 12 As shown. The solid line represents the normalized radiation pattern of the left-hand circularly polarized embodiment, and the dashed line represents the normalized radiation pattern of the right-hand circularly polarized embodiment. Figure 12 It can be seen that at 38.0 GHz, the maximum gain of the embodiment is in the θ = 0° direction.

[0083] The above description is merely one embodiment of the present invention and does not constitute any limitation on the present invention. Obviously, those skilled in the art, after understanding the content and principles of the present invention, may make various modifications and changes in form and detail without departing from the principles and structure of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the scope of the claims and protection of the present invention.

Claims

1. A broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide, characterized in that, The system includes an open substrate integrated waveguide (1) for exciting vertically polarized waves. The open substrate integrated waveguide (1) is loaded with a heel-gradient slot structure (2) and a heel-groove (3). The heel-gradient slot structure (2) is used to provide horizontally polarized waves and has a total of 2×M truncated slots (4). The truncated slots (4) are used to control the vertical polarization component of the circularly polarized waves. The heel-groove (3) is loaded at the open end of the open substrate integrated waveguide (1) and is used to excite new circularly polarized resonant points. The open substrate integrated waveguide (1) includes a dielectric substrate (11) with metal vias (12). The front and back patterns of the dielectric substrate (11) are heel-to-heel. The front side is printed with a first metal ground plane (131) and a first gradient slot structure (141), and the back side is printed with a second metal ground plane (132) and a second gradient slot structure (142). The first gradient slot structure (141) includes a first gradient metal layer (181) and M first cut-off slots (171) etched on the first gradient metal layer (181); the second gradient slot structure (142) includes a second gradient metal layer (182) and M second cut-off slots (172) etched on the second gradient metal layer (182); the first gradient metal layer (181) is connected to the first metal floor (131), and the second gradient metal layer (182) is connected to the second metal floor (132); the first gradient slot structure (141) and the second gradient slot structure (142) form the heel-to-heel gradient slot structure (2), and the M first cut-off slots (171) and the M second cut-off slots (172) form the 2×M cut-off slots (4); In the first truncated slot (171) and / or the second truncated slot (172), the length of each slot gradually increases or decreases in sequence, the width gradually decreases or increases in sequence, and the distance between the central axes of adjacent slots gradually decreases or increases in sequence.

2. The broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide according to claim 1, characterized in that, Both the first truncated slot (171) and the second truncated slot (172) satisfy the following formula: 0.25l ε1 <L<0.25l ε2 In the formula, λ ε1 It is the wavelength of the medium corresponding to the highest operating frequency of the antenna, λ. ε2 L is the wavelength of the medium corresponding to the lowest operating frequency of the antenna, and L is the distance between the central axes of adjacent slots in the M first truncated slots (171) or M second truncated slots (172).

3. The broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide according to claim 1, characterized in that, The metal through holes (12) are arranged in three rows, each metal through hole (12) connecting the first metal plate (131) and the second metal plate (132). The center line of the three rows of metal through holes (12) forms a U-shape, and the U-shaped opening faces the heel-to-heel gradient groove structure (2). A first circular groove (151) is etched on the first metal plate (131), and a second circular groove (152) is etched on the second metal plate (132).

4. The broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide according to claim 3, characterized in that, The three columns of metal through holes (12) satisfy the following formula: D < P < 2D D / l g <0.2 0.05<P / l c <0.25 In the formula, D is the diameter of the metal through hole (12), P is the distance between the centers of adjacent metal through holes in the same column, and λ g λ is the waveguide wavelength of the open substrate integrated waveguide (1). c It is the cutoff wavelength of the open substrate integrated waveguide (1).

5. The broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide according to claim 1, characterized in that, The dielectric substrate (11) is a cuboid. The first metal ground plane (131) and the second metal ground plane (132) are both rectangular, with the same width as the dielectric substrate (11) and a length less than the length of the dielectric substrate (11). The first gradient metal layer (181) and the second gradient metal layer (182) are both three-sided structures. The first gradient metal layer (181) has a first side connected to a portion of the wide side of the first metal ground plane (131), a second side flush with one longitudinal edge of the dielectric substrate (11), and a third side that is a gradient edge. In the direction closer to the first metal floor (131), the distance between the gradient edge and the second edge gradually increases, and the length direction of the first truncated slot (171) is parallel to the direction of the first edge; the second gradient metal layer (182) has a first edge connected to a portion of the wide edge of the second metal floor (132), a second edge flush with a length direction edge of the dielectric substrate (11), and a third edge that is a gradient edge. In the direction closer to the second metal floor (132), the distance between the gradient edge and the second edge gradually increases, and the length direction of the second truncated slot (172) is parallel to the direction of the first edge.

6. The broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide according to claim 5, characterized in that, The gradient edge can be a straight line, a broken line, or an arc.

7. The broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide according to claim 5, characterized in that, From the direction away from the first metal floor (131) to the direction closer to the first metal floor (131), the length of the M first truncated gaps (171) gradually increases, the width gradually decreases, and the distance between the central axes of adjacent gaps gradually decreases. From the direction away from the second metal floor (132) towards the second metal floor (132), the length of the M second truncated slits (172) gradually increases, the width gradually decreases, and the distance between the central axes of adjacent slits gradually decreases.

8. The broadband circularly polarized millimeter-wave antenna based on a substrate integrated waveguide according to claim 7, characterized in that, A first groove (161) is etched on one side of the first metal floor (131), and a second groove (162) is etched on the other side of the second metal floor (132). Both the first groove (161) and the second groove (162) are rectangular grooves, forming the heel groove (3).

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