Broadband millimeter wave circularly polarized antenna based on SIW feed

Abstract

The invention provides a broadband millimeter wave circularly polarized antenna based on SIW feed. The broadband millimeter wave circularly polarized antenna comprises a first dielectric plate and a second dielectric plate which are aligned and superposed from top to bottom, a second metal layer is arranged on the upper surface of the first dielectric plate, a first metal layer is arranged on the lower surface of the first dielectric plate, a feed coupling gap is etched in the first metal layer, and a third metalized through hole group is arranged in the first dielectric plate; a metal ground is arranged on the lower surface of the second dielectric plate, a first metalized through hole group and a second metalized through hole group are arranged in the second dielectric plate, and a plurality of metalized through holes in the first metalized through hole group are sequentially connected to form a substrate integrated waveguide transmission structure with a closed tail end, namely an SIW feed structure. The working bandwidth of the circularly polarized antenna in the millimeter wave frequency band is greatly expanded, low-axial-ratio and high-gain left-hand circularly polarized waves can be realized in the working frequency band, the structural design is simple and reasonable, the profile is low, and the circularly polarized antenna has important practical significance for a mobile communication system.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and particularly relates to a broadband millimeter-wave circularly polarized antenna fed by SIW. Background Art

[0002] At present, the number of devices, the transmission environment, and the communication quality have put forward higher requirements for the design of antennas. Compared with Sub-6GHz, millimeter-wave antennas with higher frequencies have smaller volumes, lower power consumption, and can effectively improve the resolution and security of data transmission, and also ensure the requirements of ultra-high transmission rate, ultra-low latency, and large information capacity required for 5G communication. As a radio frequency device of the terminal, the antenna is responsible for signal transmission and reception. It not only needs to ensure the signal transmission rate, but also needs to consider the integrity of the received and transmitted signals. Satellite communication uses circularly polarized antennas because circularly polarized electromagnetic waves can overcome the Faraday rotation that occurs when passing through the ionosphere. On the other hand, compared with linearly polarized waves, circularly polarized waves are easier to achieve polarization matching, reduce the influence of multipath effects, overcome the influence of various climates, and reduce mismatch.

[0003] Compared with waves in the microwave state, waves at millimeter-wave frequencies will experience more severe path loss and blockage, which will seriously reduce the signal-to-noise ratio. Due to the long communication distance, the huge propagation loss caused by oxygen absorption in the atmosphere, and dynamic weather and other factors will also cause loss of electromagnetic wave energy. The millimeter-wave antenna applied to satellite communication not only needs to be able to perform circular polarization radiation, but also needs to have higher gain and wider operating bandwidth. With the rapid development of millimeter-wave communication systems, the necessity and practical significance of proposing a new type of millimeter-wave antenna are self-evident. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a broadband millimeter-wave circularly polarized antenna fed by SIW in view of the above-mentioned deficiencies of the prior art. The present invention greatly expands the operating bandwidth of circularly polarized antennas in the millimeter-wave band, can achieve left-handed circularly polarized waves with low axial ratio and high gain within the operating frequency band, and has a simple, reasonable, and low-profile structure design, which has important practical significance for mobile communication systems.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: a broadband millimeter-wave circularly polarized antenna fed by SIW, including a first dielectric plate, and a second dielectric plate is disposed directly below the first dielectric plate;

[0006] A second metal layer is disposed on the upper surface of the first dielectric plate, a first metal layer is disposed on the lower surface of the first dielectric plate, a feed coupling slot is etched on the first metal layer, and a third metallized via hole group is disposed in the first dielectric plate;

[0007] A metal ground is provided on the lower surface of the second dielectric plate, and a first metallized via hole group and a second metallized via hole group are provided in the second dielectric plate.

[0008] Preferably, the second metal layer includes a pair of parallelogram metal patches, a pair of first parasitic patches, a first rectangular patch, a second rectangular patch, a third rectangular patch, and a fourth rectangular patch; the first rectangular patch takes the y-axis as the horizontal line and rotates clockwise by an angle θ1; the fourth rectangular patch takes the y-axis as the horizontal line and rotates clockwise by an angle θ2; θ1 is 45°, and θ2 is 135°;

[0009] The shape of a pair of the first parasitic patches is parallelogram; a pair of the parallelogram metal patches are symmetrically distributed on both sides of the feed coupling slot.

[0010] Preferably, the third metallized via hole group includes four nineteenth metallized via holes, and the four nineteenth metallized via holes are evenly divided into two rows and symmetrically arranged on both sides of the feed coupling slot; the upper end of each nineteenth metallized via hole is connected to the parallelogram metal patch, and the lower end is connected to the first metal layer.

[0011] Preferably, the first metallized via hole group is formed by connecting a plurality of metallized via holes to form a substrate integrated waveguide transmission structure, and the first metallized via hole group includes a first metallized via hole, a second metallized via hole, a third metallized via hole, a fourth metallized via hole, a fifth metallized via hole, a sixth metallized via hole, a seventh metallized via hole, an eighth metallized via hole, a ninth metallized via hole, a tenth metallized via hole, an eleventh metallized via hole, a twelfth metallized via hole, a thirteenth metallized via hole, a fourteenth metallized via hole, a fifteenth metallized via hole, a sixteenth metallized via hole, a seventeenth metallized via hole, and an eighteenth metallized via hole.

[0012] Preferably, the second metallized via hole group includes 3 metallized via holes, and the second metallized via hole group penetrates through the first metal layer, the second dielectric plate, and the metal ground; the second metallized via hole group is located between the feed coupling slot and the end of the substrate integrated waveguide transmission structure.

[0013] Preferably, the widths between the first metallized via and the second metallized via, and between the third metallized via and the fourth metallized via are both 2.8 mm, and the widths between the fifth metallized via and the sixth metallized via, and between the seventh metallized via and the eighth metallized via are both 3.4 mm; the widths between the ninth metallized via and the tenth metallized via, between the eleventh metallized via and the twelfth metallized via, and between the thirteenth metallized via and the eighteenth metallized via are all 3 mm, and the widths between the fourteenth metallized via and the fifteenth metallized via, between the fifteenth metallized via and the sixteenth metallized via, and between the sixteenth metallized via and the seventeenth metallized via are all 0.6 mm.

[0014] Preferably, the ninth metallized via and the tenth metallized via are semi-cylindrical, and the first metallized via, the second metallized via, the third metallized via, the fourth metallized via, the fifth metallized via, the sixth metallized via, the seventh metallized via, the eighth metallized via, the eleventh metallized via, the twelfth metallized via, the thirteenth metallized via, the fourteenth metallized via, the fifteenth metallized via, the sixteenth metallized via, the seventeenth metallized via and the eighteenth metallized via are all cylindrical.

[0015] Preferably, both the first dielectric substrate and the second dielectric substrate are made of Rogers 5880 material with a thickness of 0.762 mm and a dielectric constant of 2.2.

[0016] The present invention has the following advantages compared with the prior art:

[0017] 1. In the present invention, the metal ground, the second dielectric substrate and the first metal layer form a feeding layer, and the first dielectric substrate and the second metal layer form a radiation layer. The feeding layer is provided with an irregular substrate integrated waveguide transmission structure with a closed end at the end. A rectangular feeding coupling slot is etched on the first metal layer to connect the feeding layer and the radiation layer. This structure can effectively control the electromagnetic energy from the feeding layer through the feeding coupling slot to the radiation layer; the radiation patch located in the radiation layer works in the resonance mode, equivalent to a pair of electric dipoles. The electromagnetic wave passes from the feeding layer through the feeding coupling slot to below the radiation patch pair and then radiates to the free space after passing through the patch. The feeding coupling slot is equivalent to a magnetic dipole. By adjusting the thickness of the radiation layer and the position of the second metal layer relative to the feeding coupling slot, the phase difference between the electric dipole and the magnetic dipole is adjusted so that the two have a 90° phase difference within a relatively wide operating frequency band, realizing the radiation mode of circularly polarized waves; thus, the axial ratio bandwidth of the circularly polarized antenna operating in the narrow frequency mode is broadened into a wide frequency band operating mode, greatly expanding the operating frequency band of the circularly polarized antenna.

[0018] 2. The second metal layer in the present invention includes a pair of parallelogram metal patches, a pair of first parasitic patches, and four rectangular patches, effectively increasing the radiation surface and improving the antenna gain.

[0019] 3. The present invention provides a second metallized via group between the feed coupling slot and the end of the rectangular substrate integrated waveguide transmission structure, forming a short-circuit matching structure, which can finely adjust the electromagnetic field distribution nearby and improve the impedance matching characteristics.

[0020] 4. The present invention changes the width of the traditional rectangular substrate integrated waveguide transmission structure near the feed coupling slot to be rectangular, forming an inductive window. The electromagnetic energy in the rectangular substrate integrated waveguide transmission structure is coupled to the feed coupling slot through the inductive window, expanding the impedance bandwidth of the antenna.

[0021] 5. The present invention maintains excellent electromagnetic characteristics, has a directional circular polarization radiation characteristic within a very wide frequency band, the antenna pattern maintains good consistency within the wide frequency band, has excellent impedance bandwidth characteristics and axial ratio bandwidth characteristics, and is conducive to expanding into a large-scale broadband circular polarization array antenna.

[0022] 6. The structure design of the present invention is simple and reasonable, the antenna size is compact, the overall size is only 0.9λ×0.9λ×0.304λ, where λ is the resonant wavelength corresponding to the center frequency of the antenna. The axial ratio bandwidth is relatively wide, the feeding structure is simple, it has a relatively wide bandwidth, is easy to process, and because it is fabricated on a dielectric substrate and uses PCB technology, the antenna has a low profile, light weight, is conducive to mass production, and has broad application prospects.

[0023] The following further elaborates on the present invention in conjunction with the accompanying drawings and embodiments. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the hierarchical structure of the broadband millimeter-wave circular polarization antenna based on SIW feeding provided by the embodiment of the present invention;

[0025] Figure 2 It is a side view of the broadband millimeter-wave circular polarization antenna based on SIW feeding provided by the embodiment of the present invention;

[0026] Figure 3 It is a top view of the second metal layer of the broadband millimeter-wave circular polarization antenna based on SIW feeding provided by the embodiment of the present invention;

[0027] Figure 4 It is a top view of the first dielectric plate of the broadband millimeter-wave circular polarization antenna based on SIW feeding provided by the embodiment of the present invention;

[0028] Figure 5 It is a top view of the second dielectric plate of the broadband millimeter-wave circular polarization antenna based on SIW feeding provided by the embodiment of the present invention;

[0029] Figure 6 The simulation result diagram of the relationship between the reflection coefficient and frequency of a single partial reflection unit of the broadband millimeter-wave circularly polarized antenna fed by SIW provided by the embodiment of the present invention;

[0030] Figure 7 The simulation result diagram of the relationship between the axial ratio and frequency of the broadband millimeter-wave circularly polarized antenna fed by SIW provided by the embodiment of the present invention;

[0031] Figure 8 The far-field radiation pattern of the broadband millimeter-wave circularly polarized antenna fed by SIW provided by the embodiment of the present invention when operating in the left-handed and right-handed circular polarization states at phi = 0° at 55 GHz;

[0032] Figure 9 The far-field radiation pattern of the broadband millimeter-wave circularly polarized antenna fed by SIW provided by the embodiment of the present invention when operating in the left-handed and right-handed circular polarization states at phi = 90° at 55 GHz;

[0033] Figure 10 The far-field radiation pattern of the broadband millimeter-wave circularly polarized antenna fed by SIW provided by the embodiment of the present invention when operating in the left-handed and right-handed circular polarization states at phi = 0° at 61 GHz;

[0034] Figure 11 The far-field radiation pattern of the broadband millimeter-wave circularly polarized antenna fed by SIW provided by the embodiment of the present invention when operating in the left-handed and right-handed circular polarization states at phi = 90° at 61 GHz;

[0035] Figure 12 The far-field radiation pattern of the broadband millimeter-wave circularly polarized antenna fed by SIW provided by the embodiment of the present invention when operating in the left-handed and right-handed states at phi = 0° at 66 GHz;

[0036] Figure 13 The far-field radiation pattern of the broadband millimeter-wave circularly polarized antenna fed by SIW provided by the embodiment of the present invention when operating in the left-handed and right-handed states at phi = 90° at 66 GHz;

[0037] Figure 14 The simulation result diagram of the relationship between the gain and frequency of the broadband millimeter-wave circularly polarized antenna fed by SIW provided by the embodiment of the present invention.

[0038] Explanation of the reference numerals: 1. second metal layer; 101. first parasitic patch; 102. first rectangular patch; 103. parallelogram metal patch; 104. second rectangular patch; 105. third rectangular patch; 106. fourth rectangular patch; 2. first dielectric plate; 3. third metallized through hole group; 301. nineteenth metallized through hole; 4. first metal layer; 401. feed coupling gap; 5. second dielectric plate; 6. first metallized through hole group; 601. first metallized through hole; 602. second metallized through hole; 603. third metallized through hole; 604. fourth metal 605, fifth metallized through hole; 606, sixth metallized through hole; 607, seventh metallized through hole; 608, eighth metallized through hole; 609, ninth metallized through hole; 610, tenth metallized through hole; 611, eleventh metallized through hole; 612, twelfth metallized through hole; 613, thirteenth metallized through hole; 614, fourteenth metallized through hole; 615, fifteenth metallized through hole; 616, sixteenth metallized through hole; 617, seventeenth metallized through hole; 618, eighteenth metallized through hole; 7, second metallized through hole group; 8, metal ground. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] This embodiment provides a broadband millimeter wave circularly polarized antenna based on SIW feeding, such as Figures 1-5 As shown, it includes a first dielectric plate 2, and a second dielectric plate 5 is arranged directly below the first dielectric plate 2; a second metal layer 1 is arranged on the upper surface of the first dielectric plate 2, a first metal layer 4 is arranged on the lower surface of the first dielectric plate 2, a feed coupling slot 401 is etched on the first metal layer 4, and a third metalized through hole group 3 is arranged in the first dielectric plate 2; a metal ground 8 is arranged on the lower surface of the second dielectric plate 5, and a first metalized through hole group 6 and a second metalized through hole group 7 are arranged in the second dielectric plate 5;

[0042] like Figure 1 As shown, the Z-axis direction in the three-dimensional rectangular coordinate system is the thickness direction of the first dielectric plate 2 and the second dielectric plate 5, and the first dielectric plate 2 and the second dielectric plate 5 are arranged in an overlapping and aligned manner in the Z-axis direction. Figure 1 , Figure 2 and Figure 5As shown, a second via hole group 7 is provided in the second dielectric plate 5, and the second via hole group 7 penetrates through the first metal layer 4, the second dielectric plate 5, and the metal ground 8; a feeding coupling slot 401 is etched on the first metal layer 4, and the feeding coupling slot 401 is located on the rectangular substrate integrated waveguide transmission structure, that is, the projection of the feeding coupling slot 401 on the XOY plane is located within the range surrounded by the projection of the first via hole group 6 on the XOY plane;

[0043] The first dielectric plate 2 and the second metal layer 1 form a radiation layer, and the first metal layer 4, the second dielectric plate 5, and the metal ground 8 form a feeding layer. In the feeding layer, a substrate integrated waveguide transmission structure with a closed end formed by sequentially connecting a plurality of via holes in the first via hole group 6, that is, an SIW feeding structure, is provided. A feeding coupling slot 401 for connecting the feeding layer and the radiation layer is etched on the first metal layer 4. This structure can effectively control the electromagnetic energy from the feeding layer to the radiation layer through the feeding coupling slot 401. The second metal layer 1 can adjust the axial ratio (AR) bandwidth, impedance bandwidth, and radiation pattern of the antenna; the first via hole group 6 includes a first via hole 601, a second via hole 602, a third via hole 603, a fourth via hole 604, a fifth via hole 605, a sixth via hole 606, a seventh via hole 607, an eighth via hole 608, a ninth via hole 609, a tenth via hole 610, an eleventh via hole 611, a twelfth via hole 612, a thirteenth via hole 613, a fourteenth via hole 614, a fifteenth via hole 615, a sixteenth via hole 616, a seventeenth via hole 617, and an eighteenth via hole 618;

[0044] The second metal layer 1 located in the radiation layer operates in a resonant mode. The second metal layer 1 includes a pair of parallelogram metal patches 103, a pair of first parasitic patches 101, a first rectangular patch 102, a second rectangular patch 104, a third rectangular patch 105, and a fourth rectangular patch 106. Electromagnetic waves pass from the feeding layer through the feeding coupling slot 401 to the lower part of the parallelogram metal patch 103, and are coupled to the first parasitic patch 101, the first rectangular patch 102, the second rectangular patch 104, the third rectangular patch 105, and the fourth rectangular patch 106 through the parallelogram metal patch 103, and are radiated into free space after passing through the second metal layer 1. The feeding coupling slot 401 is equivalent to a magnetic dipole; after the radiation slot is loaded on the second metal layer 1, the whole patch can be regarded as an electric dipole, and together with the magnetic dipole formed by the feeding coupling slot 401, a circularly polarized wave is formed;

[0045] By arranging magnetoelectric dipoles in parallel, two electric fields with perpendicular vector directions are generated in the far field region. By adjusting the thickness of the radiation layer, the structure of the second metal layer 1, or the distance between the second metal layer 1 and the feed coupling slot 401, the phase difference between the electric dipole and the magnetic dipole is adjusted to obtain two excitations with equal amplitude and a 90° phase difference, which respectively excite the antenna element to perform circular polarization radiation in the far field, thereby broadening the axial ratio bandwidth of the circular polarization antenna operating in the narrow frequency mode into a wide frequency band operating mode, greatly expanding the operating frequency band of the circular polarization antenna, and at the same time, a complementary antenna with consistent E-plane and H-plane directions can be obtained; Figure 1 The radiation pattern of the complementary antenna is stably distributed within the impedance bandwidth;

[0046] A pair of parallelogram metal patches 103 are each formed by chamfering a rectangular metal patch with a length (ld) of 2.2 mm and a width (wd) of 0.5 mm, and the long side distance of the chamfer is 0.55 mm and the short side distance is 0.5 mm. The pair of parallelogram metal patches 103 are symmetrically distributed on both sides of the feed coupling slot 401; The third metallized via group 3 includes four nineteenth metallized vias 301, and the four nineteenth metallized vias 301 are evenly divided into two rows and symmetrically arranged on both sides of the feed coupling slot 401; The upper end of each nineteenth metallized via 301 is connected to the parallelogram metal patch 103, and the lower end is connected to the first metal layer 4. The parallelogram metal patch 103 is excited by the third metallized via group 3 and the feed coupling slot 401;

[0047] The first parasitic patch 101 is formed by chamfering a rectangular metal patch with a length (ld5) of 1.4 mm and a width (wd5) of 0.4 mm, and the chamfer radius is 0.4 mm, which increases the axial ratio bandwidth;

[0048] The first rectangular patch 102, the second rectangular patch 104, the third rectangular patch 105, and the fourth rectangular patch 106 are all rectangular patches with a length (y2) of 1 mm and a width (w2) of 0.5 mm. The first rectangular patch 102 takes the y-axis as the horizontal line and rotates clockwise by an angle θ1, where θ1 is 45°; The fourth rectangular patch 106 takes the y-axis as the horizontal line and rotates clockwise by an angle θ2, where θ2 is 135°; By rotating and placing them around the perimeter, the axial ratio bandwidth of the antenna is broadened.

[0049] The first metal layer 4 is located between the lower surface of the first dielectric plate 2 and the upper surface of the second dielectric plate 5. The energy fed into the feed port is coupled to the radiation patch, i.e., the second metal layer 1, through the feed coupling slot 401 etched in the first metal layer 4. By controlling the size and shape of the feed coupling slot 401, the current mode, the coupled energy, and the resonant frequency can be changed, thereby affecting the magnitude of the antenna input impedance. The feed coupling slot 401 is finally determined to be a rectangular slot with a length (ls) of 2.5 mm and a width (ws) of 0.4 mm.

[0050] The transmission mode of the substrate integrated waveguide is the quasi-TE10 mode. In order to make the SIW transmission line operate in the main mode TE10 in the millimeter-wave band, Equations (1) and (2) show the relationship between the operating frequency band of the antenna and the parameters of the antenna.

[0051]

[0052] Among them, f TEmn represents the single-mode operating bandwidth of the antenna, w1 represents the width of the substrate integrated waveguide transmission structure, d1 represents the aperture of the first via group 6, s represents the spacing between two adjacent vias in the first via group 6, m and n represent the mode TEmn propagated by the substrate integrated waveguide transmission structure, a represents the width of the rectangular waveguide corresponding to the substrate integrated waveguide transmission structure, h2 represents the height of the rectangular substrate integrated waveguide transmission structure, ε r represents the relative dielectric constant of the second dielectric plate 5, μ r represents the relative permeability of the second dielectric plate 5, and c represents the speed of light in vacuum.

[0053] The height (h2) of the substrate integrated waveguide transmission structure is 0.762 mm, the aperture (d1) of the first via group 6 is 0.4 mm, the spacing s between two adjacent vias in the first via group 6 is 0.6 mm, the relative dielectric constant ε r of the second dielectric plate 5 is 2.2, the relative permeability μ r is 1, and when the overall width of the substrate integrated waveguide transmission structure is w1 = 3 mm, in order to further adjust the antenna impedance matching, the widths between the first via 601 and the second via 602, and between the third via 603 and the fourth via 604 in the first via group 6 are adjusted to 2.8 mm, and the widths between the fifth via 605 and the sixth via 606, and between the seventh via 607 and the eighth via 608 are adjusted to 3.4 mm. The operating bandwidth of the antenna is 52.4 - 68.8 GHz.

[0054] The second via group 7 is arranged between the feed coupling slot 401 and the end of the substrate integrated waveguide transmission structure to form a short-circuit matching structure, which can finely adjust the electromagnetic field distribution nearby and improve the impedance matching characteristics.

[0055] The substrate integrated waveguide transmission structure changes the transmission line width near the feed coupling slot 401 to form an inductive window. The electromagnetic energy in the rectangular substrate integrated waveguide transmission structure is coupled to the feed coupling slot 401 through the inductive window, expanding the impedance bandwidth of the antenna.

[0056] In this embodiment, the antenna maintains excellent electromagnetic characteristics, has a directional circular polarization radiation characteristic within a very wide frequency band, the antenna pattern maintains good consistency within the wide frequency band, has excellent impedance bandwidth characteristics and axial ratio bandwidth characteristics, which is conducive to expanding into a large-scale broadband circular polarization array antenna.

[0057] In this embodiment, the radiation layer and the feeding layer can be respectively printed on the same dielectric board and are connected through the interlayer feeding coupling slot 401. There is no need to add other metal structures, and the structure is simple. The radiation layer and the feeding layer can be separately designed, processed and combined, and processed using the PCB process, which is conducive to mass production. Adopting a planar structure, it is easy to be integrated with the front-end equipment.

[0058] For the broadband millimeter-wave circular polarization antenna described in this embodiment, a simulation experiment is carried out on its working performance.

[0059] Using the simulation software ANSYS HFSS, the reflection coefficient, circular polarization gain and axial ratio of the broadband millimeter-wave circular polarization antenna in the above embodiment are simulated and calculated, and the left-handed circular polarization pattern and right-handed circular polarization pattern of the broadband millimeter-wave circular polarization antenna in the above embodiment at the 55 GHz frequency point, 61 GHz frequency point, 66 GHz frequency point in the XOZ plane and YOZ plane are respectively simulated and calculated. The simulation results are as Figures 6-14 shown.

[0060] Refer to Figure 6 , the abscissa represents the operating frequency of the antenna, and the ordinate represents the reflection coefficient of the antenna. It can be seen from Figure 6 that the broadband millimeter-wave circular polarization antenna in this embodiment operates between the bandwidths of 50.6 - 70.39 GHz, and its reflection coefficient remains less than -10 dB.

[0061] Refer to Figure 7 , the abscissa represents the operating frequency of the antenna, and the ordinate represents the axial ratio of the antenna. It can be seen from Figure 7 that the broadband millimeter-wave circular polarization antenna in this embodiment operates between the bandwidths of 52.2 - 67.6 GHz, and its axial ratio is less than 3 dB. Compared with the prior art, the broadband millimeter-wave circular polarization antenna in this embodiment effectively improves the axial ratio bandwidth of the circular polarization antenna.

[0062] Refer to Figure 8 , which are the simulated left-handed circular polarization pattern and right-handed circular polarization pattern of the X0Z plane at 55 GHz. It can be seen from Figure 8 that the broadband millimeter-wave circular polarization antenna in this embodiment radiates left-handed circular polarization waves in the X0Z plane at 55 GHz.

[0063] Refer to Figure 9 , which are the simulated left-handed circular polarization pattern and right-handed circular polarization pattern of the Y0Z plane at 55 GHz. It can be seen from Figure 9It can be seen that the broadband millimeter-wave circularly polarized antenna in this embodiment radiates left-handed circularly polarized waves in the Y0Z plane at 55 GHz.

[0064] Referring to Figure 10 , they are the simulated left-handed circular polarization pattern and right-handed circular polarization pattern in the X0Z plane at 61 GHz. It can be seen from Figure 10 that the broadband millimeter-wave circularly polarized antenna in this embodiment radiates left-handed circularly polarized waves in the X0Z plane at 61 GHz.

[0065] Referring to Figure 11 , they are the simulated left-handed circular polarization pattern and right-handed circular polarization pattern in the Y0Z plane at 61 GHz. It can be seen from Figure 11 that the broadband millimeter-wave circularly polarized antenna in this embodiment radiates left-handed circularly polarized waves in the Y0Z plane at 61 GHz.

[0066] Referring to Figure 12 , they are the simulated left-handed circular polarization pattern and right-handed circular polarization pattern in the X0Z plane at 66 GHz. It can be seen from Figure 12 that the broadband millimeter-wave circularly polarized antenna in this embodiment radiates left-handed circularly polarized waves in the X0Z plane at 66 GHz.

[0067] Referring to Figure 13 , they are the simulated left-handed circular polarization pattern and right-handed circular polarization pattern in the Y0Z plane at 66 GHz. It can be seen from Figure 13 that the broadband millimeter-wave circularly polarized antenna in this embodiment radiates left-handed circularly polarized waves in the Y0Z plane at 66 GHz.

[0068] Referring to Figure 14 , the abscissa represents the operating frequency of the antenna, and the ordinate represents the circular polarization gain of the antenna. It can be seen from Figure 14 that the broadband millimeter-wave circularly polarized antenna in this embodiment is a left-handed circularly polarized antenna, with a maximum gain of approximately 8.5 dBic. In the frequency range of 52.2 - 67.6 GHz, the left-handed circular polarization gain is greater than 8 dBic.

[0069] In summary, for a broadband millimeter-wave antenna based on SIW feeding according to the present invention, a second metal layer 1, a first dielectric plate 2, a first metal layer 4, a second dielectric plate 5, and a metal ground 8 are sequentially arranged in parallel from top to bottom. The second metal layer 1 is located on the upper surface of the first dielectric plate 2 and together with the first dielectric plate 2 forms a radiation layer. A rectangular feeding coupling slot 401 is etched on the first metal layer 4, and a substrate integrated waveguide transmission structure is arranged in the second dielectric plate 5. The metal ground 8, the second dielectric plate 5, and the first metal layer 4 together form a feeding layer, and energy is fed to the radiation layer through the feeding coupling slot 401. At the same time, the second metal layer 1 includes a pair of parallelogram metal patches 103, a pair of first parasitic patches 101, a first rectangular patch 102, a second rectangular patch 104, a third rectangular patch 105, and a fourth rectangular patch 106. Through operations such as chamfering and rotation, the antenna can obtain a relatively wide 3-dB gain bandwidth, and the antenna can obtain a relatively large gain without arraying.

[0070] The above simulation results show that the left-handed circularly polarized antenna of this embodiment has a relatively wide operating bandwidth, from 52.2 GHz to 67.6 GHz, and the maximum circular polarization gain within the operating frequency band is about 8.5 dBic. It can be seen from the radiation pattern of the selected intermediate frequency point that the left-handed circularly polarized antenna of this embodiment has stable radiation characteristics.

[0071] The above description is only a preferred embodiment of the present invention and does not impose any limitations on the present invention. Any simple modification, change, and equivalent change made to the above embodiments according to the technical essence of the invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A broadband millimeter-wave circularly polarized antenna based on SIW feeding, characterized in that: It comprises a first dielectric plate (2), wherein a second dielectric plate (5) is arranged directly below the first dielectric plate (2); The upper surface of the first dielectric plate (2) is provided with a second metal layer (1), the lower surface of the first dielectric plate (2) is provided with a first metal layer (4), a feed coupling gap (401) is etched on the first metal layer (4), and a third metalized through hole group (3) is provided in the first dielectric plate (2); The lower surface of the second dielectric plate (5) is provided with a metal ground (8), and the second dielectric plate (5) is provided with a first metallized through hole group (6) and a second metallized through hole group (7).

2. A broadband millimeter wave circularly polarized antenna based on SIW feeding according to claim 1, characterized in that: The second metal layer (1) comprises a pair of parallelogram metal patches (103), a pair of first parasitic patches (101), a first rectangular patch (102), a second rectangular patch (104), a third rectangular patch (105) and a fourth rectangular patch (106); the first rectangular patch (102) is rotated clockwise by an angle of θ1 with the y-axis as the horizontal line; the fourth rectangular patch (106) is rotated clockwise by an angle of θ2 with the y-axis as the horizontal line; θ1 is 45° and θ2 is 135°; The pair of first parasitic patches (101) are in the shape of a parallelogram; and the pair of parallelogram metal patches (103) are symmetrically distributed on both sides of the feeding coupling slot (401).

3. A broadband millimeter wave circularly polarized antenna based on SIW feeding according to claim 2, characterized in that: The third metallized through hole group (3) comprises four nineteenth metallized through holes (301), and the four nineteenth metallized through holes (301) are evenly divided into two rows and symmetrically arranged on both sides of the feed coupling gap (401); the upper end of each of the nineteenth metallized through holes (301) is connected to the parallelogram metal patch (103), and the lower end is connected to the first metal layer (4).

4. A broadband millimeter wave circularly polarized antenna based on SIW feeding according to claim 1, characterized in that: The first metallized through hole group (6) is connected by a plurality of metallized through holes to form a substrate integrated waveguide transmission structure, and the first metallized through hole group (6) includes a first metallized through hole (601), a second metallized through hole (602), a third metallized through hole (603), a fourth metallized through hole (604), a fifth metallized through hole (605), a sixth metallized through hole (606), a seventh metallized through hole (607), an eighth metallized through hole (608), a ninth metallized through hole (609), a tenth metallized through hole (610), an eleventh metallized through hole (611), a twelfth metallized through hole (612), a thirteenth metallized through hole (613), a fourteenth metallized through hole (614), a fifteenth metallized through hole (615), a sixteenth metallized through hole (616), a seventeenth metallized through hole (617) and an eighteenth metallized through hole (618).

5. A broadband millimeter wave circularly polarized antenna based on SIW feeding according to claim 4, characterized in that: The second metallized through hole group (7) comprises three metallized through holes, and the second metallized through hole group (7) penetrates the first metal layer (4), the second dielectric plate (5) and the metal ground (8); the second metallized through hole group (7) is located between the feed coupling slot (401) and the end of the substrate integrated waveguide transmission structure.

6. A broadband millimeter wave circularly polarized antenna based on SIW feeding according to claim 4, characterized in that: The width between the first metallized through hole (601) and the second metallized through hole (602), and between the third metallized through hole (603) and the fourth metallized through hole (604) is 2.8 mm; the width between the fifth metallized through hole (605) and the sixth metallized through hole (606), and between the seventh metallized through hole (607) and the eighth metallized through hole (608) is 3.4 mm; the width between the ninth metallized through hole (609) and the tenth metallized through hole (610), and between the tenth metallized through hole (611) and the tenth metallized through hole (612) is 3.8 mm; the width between the ninth metallized through hole (609) and the tenth metallized through hole (613) is 3.8 mm; the width between the ninth metallized through hole (609) and the tenth metallized through hole (614) is 3.8 mm; the width between the ninth metallized through hole (609) and the tenth metallized through hole (615) is 3.8 mm. The width between the first metallized through hole (611) and the twelfth metallized through hole (612), and the width between the thirteenth metallized through hole (613) and the eighteenth metallized through hole (618) is 3 mm, and the width between the fourteenth metallized through hole (614) and the fifteenth metallized through hole (615), the width between the fifteenth metallized through hole (615) and the sixteenth metallized through hole (616), and the width between the sixteenth metallized through hole (616) and the seventeenth metallized through hole (617) is 0.6 mm.

7. A broadband millimeter wave circularly polarized antenna based on SIW feeding according to claim 6, characterized in that: The ninth metallized through hole (609) and the tenth metallized through hole (610) are semi-cylindrical, and the first metallized through hole (601), the second metallized through hole (602), the third metallized through hole (603), the fourth metallized through hole (604), the fifth metallized through hole (605), the sixth metallized through hole (606), the seventh metallized through hole (607), the eighth metallized through hole (608), the eleventh metallized through hole (611), the twelfth metallized through hole (612), the thirteenth metallized through hole (613), the fourteenth metallized through hole (614), the fifteenth metallized through hole (615), the sixteenth metallized through hole (616), the seventeenth metallized through hole (617) and the eighteenth metallized through hole (618) are all cylindrical.

8. The broadband millimeter wave circularly polarized antenna based on SIW feeding according to claim 1, characterized in that: The first dielectric plate (2) and the second dielectric plate (5) are both made of Rogers 5880 plates with a thickness of 0.762 mm and a dielectric constant of 2.2.

Images