Forward and backward switchable high-gain flat-top dual-mode switching Fabry-Perot cavity antenna

Abstract

The invention discloses a front-back switchable high-gain flat-top dual-mode switching Fabry-Perot cavity antenna, and belongs to the technical field of radio frequency communication, the outer end of a copper-clad layer extends to form a first port, the outer end of a siw-based waveguide transmission line extends to form a second port, and the outer end of the siw-based waveguide transmission line extends to form a second port. The dielectric substrate is arranged on one side, far away from the partial reflection surface of the upper surface, of the upper surface step type floor; the two ends of the copper-clad layer are connected with the two microstrip lines respectively, the gap is formed in the copper-clad layer, and a plurality of metal through holes are formed in the copper-clad layer and wound around the periphery of the copper-clad area; each metal through hole is communicated with the copper-clad layer and the metal ground layer; six hollow rings are etched in the upper half portion of the upper surface step type floor and the upper half portion of the lower surface step type floor, the six hollow rings are arranged in a stepped mode, four hollow rings are etched in the lower half step type reflection rings of the upper surface step type floor and the lower surface step type floor, and the four hollow rings are arranged in a stepped mode.

Description

Technical Field

[0001] The invention relates to a forward and backward switchable high-gain flat-top dual-mode switching Fabry-Perot cavity antenna, belonging to the technical field of radio frequency communication. Background Art

[0002] In millimeter wave communication systems, the 30 GHz frequency band has become the core frequency band for achieving high-speed uplink and downlink transmission due to its large bandwidth characteristics. The uplink needs to achieve wide-area uniform coverage through a horizontally polarized flat-top beam to support multi-terminal access, while the downlink relies on a vertically polarized high-gain narrow beam to improve directional transmission efficiency.

[0003] Fabry-Perot (FP) cavity antennas are considered as a candidate for achieving such dual-function radiation due to their high directivity, low profile and multi-beam control potential.

[0004] However, existing FP cavity-based designs face significant challenges in simultaneously satisfying beamforming flexibility and polarization isolation performance.

[0005] Traditional FP cavity antennas usually use a single-layer partially reflecting surface (PRS) and a ground layer to form a resonant cavity. Beam focusing or deflection is achieved by adjusting the phase gradient of the PRS unit. However, its symmetrical cavity structure causes the uplink and downlink beam polarization modes and radiation patterns to be highly coupled.

[0006] In addition, in order to achieve polarization diversity, conventional FP cavities often use orthogonal dual feed sources or polarization rotation metasurfaces. Although such designs can separate polarization channels, the equalized field distribution required for the flat-top beam (amplitude fluctuation <±1.5dB) and the sharp cutoff characteristics of the high-gain beam (sidelobe <-20dB) cannot be taken into account at the same time due to the conflict in cavity mode excitation.

[0007] Therefore, how to achieve efficient collaborative radiation of horizontally polarized flat-top beams and vertically polarized high-gain beams through innovative structural design based on the FP cavity architecture, and simultaneously resolve the contradiction between beamforming freedom, polarization isolation and high-frequency efficiency, has become a core issue that urgently needs to be broken through in this technical field.

[0008] In summary, the realization of a front-to-back switchable high-gain flat-top dual-mode switching Fabry-Perot cavity antenna has important practical significance for meeting the communication system's requirements for multi-beamforming and dual-polarization isolation, and can effectively cope with the challenges posed by future higher-performance communication terminals to antenna equipment. Summary of the invention

[0009] The main purpose of the present invention is to provide a forward and backward switchable high-gain flat-top dual-mode switching Fabry-Perot cavity antenna.

[0010] The purpose of the present invention can be achieved by adopting the following technical solutions: A front-to-back switchable high-gain flat-top dual-mode switching Fabry-Perot cavity antenna, comprising an upper surface partial reflector and a lower surface partial reflector. On the lower surface partial reflector, an upper surface stepped floor, a dielectric substrate, a copper-clad layer, a lower surface stepped floor, and a SIW-based waveguide transmission line are distributed from top to bottom; One end of the copper-clad layer extends to form Port 1, and one end of the SIW-based waveguide transmission line extends to form Port 2; the dielectric substrate is disposed on a side of the upper surface stepped floor away from the upper surface partial reflector.

[0011] Two ends of the copper-clad layer are respectively connected to two microstrip lines, a slot is opened in the copper-clad layer, and a plurality of metal vias are provided on the copper-clad layer and are wound around the periphery of the copper-clad area; each metal via communicates the copper-clad layer and the metal ground plane.

[0012] Six hollow rings are etched inside the upper half of the upper surface stepped floor and the lower surface stepped floor, and the six hollow rings are arranged in a stepped manner. Four hollow rings are etched inside the lower stepped reflection rings of the upper surface stepped floor and the lower surface stepped floor, and the four hollow rings are arranged in a stepped manner.

[0013] A plurality of mounting parts are further preset at the edges of the upper surface partial reflector and the lower surface partial reflector; the front-to-back switchable high-gain flat-top dual-mode switching Fabry-Perot cavity antenna further comprises: a plurality of metal support columns, one end of each metal support column is fixed to the dielectric substrate, and the other end of each metal support column penetrates through the upper surface stepped floor and the lower surface stepped floor and is fixed to the mounting part.

[0014] Preferably, for the upper and lower parts of the upper surface stepped floor and the lower surface stepped floor, in the upper half of the upper surface stepped floor, the outer ring radius of the stepped reflection ring decreases from bottom to top, while the inner ring radius remains unchanged to form a flat top; in the lower half of the lower surface stepped floor, the inner and outer radii of the lower surface stepped floor increase from top to bottom.

[0015] Preferably, for the upper and lower parts of the upper surface stepped floor and the lower surface stepped floor, there is a similar change trend in the outer ring radius of the stepped reflection rings in the upper and lower parts.

[0016] Preferably, the dielectric substrate is made of a plate with a dielectric constant of 2.2, the height and width of the SIW are respectively set to 0.114 times the wavelength and 0.64 times the wavelength of the center operating frequency of the antenna, and metal layers are printed on both the upper and lower surfaces of the dielectric substrate.

[0017] Preferably, two rectangular open feed slots are respectively etched on the upper and lower surfaces of the center of the dielectric substrate, and the two rectangular open feed slots are perpendicular to each other and jointly form the radiation aperture of the antenna.

[0018] Preferably, the rectangular transmission lines of the two SIW-based waveguide transmission lines are formed by arranging a series of metal vias at a certain interval, and the SIW-based waveguide transmission lines are constructed inside the dielectric substrate.

[0019] The beneficial technical effects of the present invention: The Fabry-Perot cavity antenna with forward and backward switchable high-gain flat-top dual-mode switching provided by the present invention, as Figure 1 , Figure 2 , Figure 3 and Figure 4 shown, includes an upper surface partial reflector and a lower surface partial reflector. On the lower surface partial reflector, from top to bottom, there are an upper surface stepped floor, a dielectric substrate, a copper-clad layer, a lower surface stepped floor 8, and an SIW-based waveguide transmission line; the outer end of the copper-clad layer extends a port one, and the outer end of the SIW-based waveguide transmission line 9 extends a port two; the dielectric substrate 4 is arranged on the side of the upper surface stepped floor away from the upper surface partial reflector 1.

[0020] Both ends of the copper-clad layer are respectively connected to two microstrip lines, a gap is opened in the copper-clad layer, and there are multiple metal vias on the copper-clad layer. When the diameter of the metal vias is between 0.3 mm and 0.5 mm, the impedance matching performance of the antenna is the best; For example, when the diameter of the metal vias is set to 0.4 mm, within the operating frequency band, the parameters can be further reduced by 1 - 2 dB, significantly improving the signal transmission efficiency of the antenna. They are wound around the periphery of the copper-clad area, and each metal via connects the copper-clad layer and the metal ground layer.

[0021] Six hollow rings are etched inside the upper half of the upper surface stepped floor and the lower surface stepped floor. The six hollow rings are arranged in a stepped manner. Four hollow rings are etched inside the lower stepped reflection rings of the upper surface stepped floor and the lower surface stepped floor. The four hollow rings are arranged in a stepped manner. Add 2 - 3 layers of hollow rings, and the size of each layer of hollow rings decreases according to a certain proportionality coefficient, such as a proportionality coefficient of 0.8 - 0.9; In this way, the electromagnetic characteristics of the floor can be more finely regulated, enhancing the reflection and refraction effects on electromagnetic waves. Through simulation comparison, it is found that after increasing the number of hollow ring layers and optimizing the size gradient, the gain of the antenna can be increased by 0.5 - 1 dB when radiating upward and 0.8 - 1.2 dB when radiating downward, effectively improving the radiation performance of the antenna.

[0022] Multiple installation parts are also preset at the edges of the upper surface partial reflection surface and the lower surface partial reflection surface. The width and height of the integrated waveguide SIW and the dielectric constant of the substrate are related to the operating frequency band of the antenna. To achieve the characteristics of both low profile and wideband, the dielectric substrate in this article uses a plate with a dielectric constant of 2.2. The height and width of the SIW are set to 0.114 times the wavelength and 0.64 times the wavelength of the center operating frequency of the antenna, respectively. Refer to Figure 5 As shown, these two figures show the S-parameter, gain, and axial ratio curves obtained by simulating with HFSS simulation software. It can be seen from the figures that the operating frequency band (S 11 <-10 dB) of this circularly polarized antenna is 25 GHz - 34 GHz; The axial ratio of the antenna can be reduced by 0.5 - 1 dB within the entire operating frequency band, and the cross-polarization discrimination ratio (XPD) is increased by 3 - 5 dB, making the circular polarization performance of the antenna more stable and excellent, effectively reducing signal interference and loss. Description of the Drawings

[0023] Figure 1 Is the overall three-dimensional structure decomposition schematic diagram of a preferred embodiment of the front-to-back switchable high-gain flat-top dual-mode switchable Fabry-Perot cavity antenna according to the present invention; Figure 2 Is the side view of the overall three-dimensional structure decomposition of a preferred embodiment of the front-to-back switchable high-gain flat-top dual-mode switchable Fabry-Perot cavity antenna according to the present invention; Figure 3 Is the side elevation view of the overall three-dimensional structure decomposition of a preferred embodiment of the front-to-back switchable high-gain flat-top dual-mode switchable Fabry-Perot cavity antenna according to the present invention; Figure 4 Is the schematic diagram of the waveguide transmission line structure based on SIW of a preferred embodiment of the front-to-back switchable high-gain flat-top dual-mode switchable Fabry-Perot cavity antenna according to the present invention; Figure 5 Is the normalized radiation pattern at 30 GHz of a preferred embodiment of the front-to-back switchable high-gain flat-top dual-mode switchable Fabry-Perot cavity antenna according to the present invention; Figure 6 Is a preferred embodiment of the front-to-back switchable high-gain flat-top dual-mode switchable Fabry-Perot cavity antenna according to the present invention; Figure 7 Is a preferred embodiment of the front-to-back switchable high-gain flat-top dual-mode switchable Fabry-Perot cavity antenna according to the present invention.

[0024] In the figure: 1. Upper surface partial reflector; 2. Lower surface partial reflector; 3. Upper surface stepped floor; 4. Dielectric substrate; 5. Copper-clad layer; 6. Port 1; 7. Port 2; 8. Lower surface stepped floor; 9. SIW-based waveguide transmission line; 10. Feeding slot. Detailed implementation manners

[0025] To make the technical solutions of the present invention clearer and more definite to those skilled in the art, the present invention will be further described in detail below in conjunction with embodiments and the accompanying drawings. However, the implementation manners of the present invention are not limited thereto.

[0026] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments.

[0027] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed present invention, but merely represents some embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0028] It should be noted that, without conflict, the embodiments in the present invention and the features and technical solutions in the embodiments may be combined with each other.

[0029] It should be noted that: Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0030] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present invention is normally placed, or the orientation or positional relationship commonly understood by those skilled in the art. Such terms are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention. In addition, terms such as "first" and "second" are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0031] The embodiments of the present invention will be introduced in detail below. The exemplary diagrams of the embodiments are shown in the accompanying drawings, and the elements denoted by the same reference numerals indicate the same or similar elements.

[0032] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation of the present invention.

[0033] In the description of the present invention, it should be noted that terms indicating orientations such as "bottom", "top", "above", "below", "length", "width", etc. are only used to qualitatively describe the position of the components according to the images shown in the drawings, rather than indicating that the components must be in a specific position, so it should not be construed as a limitation of the present invention.

[0034] In the embodiments of the present invention, unless otherwise specified, terms such as "connection", "support", etc. can be understood in a broad sense.

[0035] For example, the connection method can be by welding or screwing, or it can be detachable; the support can use support columns made of different materials such as foam or resin to support the dielectric substrate.

[0036] Specific operations can be processed in different ways according to the processing design.

[0037] Embodiment 1: As Figure 1 、 Figure 2 、 Figure 3 and Figure 4 shown, this embodiment proposes a Fabry-Perot cavity antenna with forward and backward switchable high-gain flat-top dual-mode switching, including an upper surface partial reflector 1 and a lower surface partial reflector 2. On the lower surface partial reflector 2, there are distributed an upper surface stepped floor 3, a dielectric substrate 4, a copper-clad layer 5, a lower surface stepped floor 8, a SIW-based waveguide transmission line 9, and an aperture-fed slot 10 from top to bottom; A port 1 extends from the outer end of the copper-clad layer 5, and a port 2 extends from the outer end of the SIW-based waveguide transmission line 9; The dielectric substrate 4 is arranged on the side of the upper surface stepped floor 3 away from the upper surface partial reflector 1, and an aperture-fed slot 10 is opened on the outer circle of the axis of the dielectric substrate 4.

[0038] Two microstrip lines are respectively connected to both ends of the copper-clad layer 5, a slot is opened in the copper-clad layer 5, and there are a plurality of metal through-holes on the copper-clad layer 5. When the diameter of the metal through-holes is between 0.3 mm and 0.5 mm, the impedance matching performance of the antenna is the best; For example, when the diameter of the metal through-holes is set to 0.4 mm, within the operating frequency band, the parameters can be further reduced by 1 - 2 dB, significantly improving the signal transmission efficiency of the antenna. It is wound around the periphery of the copper-clad area, and each metal through-hole connects the copper-clad layer 5 and the metal ground layer.

[0039] Six hollow rings are etched inside the upper surface stepped floor 3 and the upper part of the lower surface stepped floor 8. The six hollow rings are arranged in a stepped manner. Four hollow rings are etched inside the lower stepped reflection rings of the upper surface stepped floor 3 and the lower surface stepped floor 8. The four hollow rings are arranged in a stepped manner. Add 2 - 3 layers of hollow rings, and the size of each layer of hollow rings decreases according to a certain proportional coefficient, such as a proportional coefficient of 0.8 - 0.9; This can more finely regulate the electromagnetic characteristics of the floor and enhance the reflection and refraction effects on electromagnetic waves. Through simulation comparison, it is found that after increasing the number of hollow ring layers and optimizing the size gradient, the gain of the antenna can be increased by 0.5 - 1 dB when radiating upward and 0.8 - 1.2 dB when radiating downward, effectively improving the radiation performance of the antenna.

[0040] Multiple installation parts are also preset at the edges of the upper surface partial reflector 1 and the lower surface partial reflector 2. The width and height of the integrated waveguide siw and the dielectric constant of the substrate are related to the operating frequency band of the antenna. In order to achieve the characteristics of both low profile and wideband, the dielectric substrate in this article uses a plate with a dielectric constant of 2.2. The height and width of the siw are respectively set to 0.114 times the wavelength and 0.64 times the wavelength of the center operating frequency of the antenna, referring to Figure 5 As shown, these two figures show the S - parameter, gain, and axial ratio curves obtained by simulating with HFSS simulation software. It can be seen from the figure that the operating frequency band (S 11 < - 10 dB) of this circularly polarized antenna is 25 GHz - 34 GHz; The axial ratio of the antenna can be reduced by 0.5 - 1 dB within the entire operating frequency band, and the cross - polarization discrimination rate (XPD) is increased by 3 - 5 dB, making the circular polarization performance of the antenna more stable and excellent, effectively reducing signal interference and loss.

[0041] Metal layers are printed on both the upper and lower surfaces of the dielectric substrate.

[0042] The two rectangular open slots are respectively etched on the upper and lower surfaces at the center of the dielectric substrate. The two rectangular - shaped open slots are perpendicular to each other and jointly form the radiation aperture of the antenna.

[0043] The two SIW - based rectangular transmission lines on the upper surface partial reflector 1 and the lower surface partial reflector 2 are composed of a series of metal through - holes arranged at a certain interval and are constructed inside the dielectric substrate.

[0044] Embodiment 2: The two SIW - based rectangular transmission lines respectively extend from the left and right sides of the dielectric substrate towards the center of the antenna to the two rectangular open slots. Additionally, the width of the transmission line at the open slot is enlarged to surround the rectangular open slot.

[0045] Two matching ends are located at the ends of the SIW-based rectangular transmission line, and each matching end is composed of a row of metal vias.

[0046] The two matching ends at the two rectangular open slots play a role in improving impedance matching, and the impedance matching can be adjusted by adjusting its length and via pitch.

[0047] The two feeding ports of the SIW-based rectangular transmission line are respectively connected to two transmission lines, which are located at the left and right ends of the dielectric substrate respectively.

[0048] The two partial reflectors of the upper surface partial reflector 1 and the lower surface partial reflector 2 are distributed at an approximate distance of 1 wavelength from the rectangular slot in the up and down directions. Refer to Figures 6 - 7 As shown, the two figures from top to bottom are the upward and downward radiation patterns of this embodiment at 30 GHz respectively.

[0049] From Figure 6 and Figure 7 it can be seen that the antenna has a flat-top beam in upward radiation and a high-gain narrow beam in downward radiation, and the antenna generates a stable radiation pattern within the operating frequency band; From the above test results, it can be known that a Fabry-Perot cavity antenna with a switchable front and rear high-gain flat-top dual-mode proposed by the present invention realizes different up and down beam radiations with stable radiation pattern and low cross-polarization level performance.

[0050] The above-described embodiments are only one of the specific implementation manners selected after optimization in the present invention, and any modifications or changes made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0051] As shown in Table 1 is the range of modifications or changes:

[0052] The above is only a further embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any equivalent replacement or change made by those skilled in the art within the scope disclosed by the present invention according to the technical solution and concept of the present invention belongs to the protection scope of the present invention.

Claims

1. A Fabry - Perot cavity antenna with switchable front - to - back and high - gain flat - top dual - mode switching, characterized in that: It includes an upper surface partial reflecting surface (1) and a lower surface partial reflecting surface (2). On the lower surface partial reflecting surface (2), an upper surface stepped floor (3), a dielectric substrate (4), a copper-clad layer (5), a lower surface stepped floor (8), and a SIW-based waveguide transmission line (9) are distributed from top to bottom; an outer end of the copper-clad layer (5) extends a port one (6), and an outer end of the SIW-based waveguide transmission line (9) extends a port two (7); the dielectric substrate (4) is arranged on a side of the upper surface stepped floor (3) away from the upper surface partial reflecting surface (1).

2. The Fabry-Perot cavity antenna with forward and backward switchable high-gain flat-top dual-mode switching according to claim 1, characterized in that: Two ends of the copper-clad layer (5) are respectively connected to two microstrip lines. A slit is opened in the copper-clad layer (5). There are a plurality of metal vias on the copper-clad layer (5), which are wound around the periphery of the copper-clad area, and each metal via communicates the copper-clad layer (5) and the metal ground layer.

3. The Fabry - Perot cavity antenna with forward - backward switchable high - gain flat - top dual - mode switching according to claim 1, characterized in that: Six hollow rings are etched inside the upper half of the upper surface stepped floor (3) and the lower surface stepped floor (8). The six hollow rings are arranged in a stepped manner. Four hollow rings are etched inside the lower stepped reflecting rings of the upper surface stepped floor (3) and the lower surface stepped floor (8). The four hollow rings are arranged in a stepped manner.

4. The Fabry-Perot cavity antenna with forward and backward switchable high-gain flat-top dual-mode switching according to claim 2, characterized in that: A plurality of mounting parts are also preset at the edges of the upper surface partial reflecting surface (1) and the lower surface partial reflecting surface (2); the front-to-back switchable high-gain flat-top dual-mode switching Fabry-Perot cavity antenna further includes: a plurality of metal support columns. One end of each metal support column is fixed to the dielectric substrate (4), and the other end of each metal support column penetrates through the upper surface stepped floor (3) and the lower surface stepped floor (8) to be fixed to the mounting part.

5. The Fabry-Perot cavity antenna with forward and backward switchable high-gain flat-top dual-mode switching according to claim 3, characterized in that: For the upper and lower parts of the upper surface stepped floor (3) and the lower surface stepped floor (8), in the upper half of the upper surface stepped floor (3), the radius of the outer ring of the stepped reflecting ring decreases from bottom to top, while the radius of the inner ring remains unchanged to form a flat top; in the lower half of the lower surface stepped floor (8), the inner and outer radii of the lower surface stepped floor (8) increase from top to bottom.

6. The Fabry-Perot cavity antenna with forward and backward switchable high-gain flat-top dual-mode switching according to claim 4, characterized in that: For the upper and lower parts of the upper surface stepped floor (3) and the lower surface stepped floor (8), there is a similar changing trend of the outer ring radius of the stepped reflecting rings in the upper and lower parts.

7. The Fabry-Perot cavity antenna with forward and backward switchable high-gain flat-top dual-mode switching according to claim 3, characterized in that: The dielectric substrate (4) uses a plate with a dielectric constant of 2.

2. The height and width of the SIW are respectively set to 0.114 times the wavelength and 0.64 times the wavelength of the center operating frequency of the antenna.

8. The Fabry - Perot cavity antenna with forward - backward switchable high - gain flat - top dual - mode switching according to claim 5, characterized in that: Metal layers are printed on both the upper and lower surfaces of the dielectric substrate (4).

9. The Fabry-Perot cavity antenna with forward and backward switchable high-gain flat-top dual-mode switching according to claim 7, characterized in that: Two rectangular open feed slits (10) are respectively etched on the upper and lower surfaces at the center of the dielectric substrate (4). The two rectangular-shaped open feed slits (10) are perpendicular to each other and jointly form the radiation aperture of the antenna.

10. The Fabry - Perot cavity antenna with forward - backward switchable high - gain flat - top dual - mode switching according to claim 1, characterized in that: The rectangular transmission lines of the two SIW-based waveguide transmission lines (9) are composed of a series of metal vias arranged at a certain interval. The SIW-based waveguide transmission line (9) is constructed inside the dielectric substrate (4).

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