A high-gain wideband fabry-perot resonator cavity antenna

Abstract

The application discloses a high-gain wideband Fabry-Perot resonant cavity antenna, comprising a metal grounding plate, a dielectric substrate, a feed antenna, a coaxial cable and a partial reflection surface; the metal grounding plate is arranged on the lower surface of the dielectric substrate, the feed antenna is arranged at the center of the upper surface of the dielectric substrate, the coaxial cable is connected with the feed antenna after penetrating through the dielectric substrate, the partial reflection surface is arranged directly above the feed antenna and forms an air cavity between the feed antenna, the partial reflection surface is a super surface with a sticky medium layer and can effectively transmit and reflect electromagnetic waves; when the feed antenna emits electromagnetic waves, the partial reflection surface allows part of the electromagnetic waves to be reflected back to the resonant cavity and allows another part of the electromagnetic waves to transmit out through the super surface, so that the electromagnetic waves can be reflected in the resonant cavity for multiple times, the electromagnetic field of a specific wavelength is enhanced, and the high-gain wideband effect is achieved. The application solves the narrowband characteristic problem of the current Fabry-Perot resonant cavity antenna.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-gain antennas, and particularly to a high-gain wideband Fabry-Perot resonant cavity antenna. BACKGROUND

[0002] With the rapid development of the communication field, people have increasingly high demands for high-gain, miniaturized and low-cost antennas. Wideband high-gain antennas and arrays have become one of the important topics in the field of antenna research at home and abroad. As a kind of planar lens antenna, the Fabry-Perot resonant cavity antenna has attracted widespread attention due to its excellent characteristics such as high gain. The Fabry-Perot resonant cavity antenna is a high-gain antenna based on an electromagnetic band gap structure. By placing an EBG structure at a proper position directly above a radiating element, the EBG structure functions as a partial reflector, and thus this kind of antenna structure is formed. The main advantages of this kind of antenna structure are simple structure, high radiation efficiency, and high gain without the need for a complex feed network as in array antennas. However, due to the narrowband characteristics of the resonant cavity and the EBG structure, the impedance bandwidth and the gain bandwidth of this kind of antenna are relatively narrow, and widening the bandwidth of the antenna has become an urgent problem to be solved.

[0003] Explanation of terms:

[0004] Electromagnetic band gap (EBG): This structure is a periodic structure that can control the propagation of electromagnetic waves. By properly selecting the size, material and shape of the scattering medium, electromagnetic waves cannot propagate in certain frequency bands.

[0005] Wideband and narrowband: The relative bandwidth of a narrowband is less than 1%, and the relative bandwidth of a wideband is between 1% and 25%. The antenna can work in multiple frequency bands at the same time. SUMMARY

[0006] The present application aims to overcome the shortcomings and deficiencies of the prior art, and to provide a high-gain wideband Fabry-Perot resonant cavity antenna with a simple and reliable structure. The relative bandwidth of S11 of the antenna is 21.7% (16.09-20.02 GHz), the 3dB gain bandwidth is 15.68-19.96 GHz (24%), and the peak gain reaches 16.3dBi. The present application can effectively solve the narrowband problem of the existing Fabry-Perot resonant cavity antenna.

[0007] To achieve the above objectives, the technical solution provided by this invention is as follows: a high-gain broadband Fabry-Perot resonant cavity antenna, comprising: a metal ground plane, a dielectric substrate, a feed antenna, a coaxial cable, and a partial reflective surface; wherein, the metal ground plane is disposed on the lower surface of the dielectric substrate, the feed antenna is disposed at the center of the upper surface of the dielectric substrate, the coaxial cable passes through the dielectric substrate and is connected to the feed antenna, the partial reflective surface is disposed directly above the feed antenna and forms an air cavity between the feed antenna and the feed antenna, the partial reflective surface is a metasurface with an adhesive dielectric layer, which can effectively transmit and reflect electromagnetic waves. When the feed antenna emits electromagnetic waves, the partial reflective surface allows a portion of the electromagnetic waves to be reflected back into the resonant cavity, while allowing another portion of the electromagnetic waves to propagate through the metasurface, so that the electromagnetic waves can be reflected multiple times within the resonant cavity, enhancing the electromagnetic field of a specific wavelength and achieving a high-gain broadband effect.

[0008] Preferably, the partial reflective surface is composed of n×n adjacent partial reflective units, where n is an integer greater than or equal to 2. Each partial reflective unit comprises, from top to bottom, a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, and a third metal layer, stacked sequentially. The first and second dielectric layers are bonded together and are both square in size. The first and second metal layers are both chamfered rectangular metal patches, defined as first chamfered rectangular metal patches and second chamfered rectangular metal patches, located at the centers of the upper and lower surfaces of the first dielectric layer, respectively. The third metal layer is a square metal patch that completely covers the second dielectric layer. The metal patch has L-shaped slots at its four corners, a cross-shaped slot symmetrical about the center, and a large-sized chamfered rectangular slot integrated with a small-sized chamfered rectangular metal patch. The chamfers of the first chamfered rectangular metal patch, the second chamfered rectangular metal patch, the large-sized chamfered rectangular slot, and the small-sized chamfered rectangular metal patch are on the same diagonal in the same direction, and the length of the chamfers is consistent. From top to bottom, the size of the first chamfered rectangular metal patch, the second chamfered rectangular metal patch, and the small-sized chamfered rectangular metal patch increases and then decreases again. The large-sized chamfered rectangle of the second chamfered rectangular metal patch provides a phase reflection and superposition effect for electromagnetic waves.

[0009] Preferably, by adjusting the distance between a portion of the reflective surface and the metal ground plane, the reflection and interference of electromagnetic waves can be optimized.

[0010] Preferably, the feed antenna is fed by a coaxial cable, and a U-shaped groove is opened on one side near the feed end to increase the electrical length of the metal patch on part of the reflective surface and adjust the capacitance and inductance of the antenna, so that the feed antenna adds a resonant point at high frequency and widens the antenna bandwidth.

[0011] Preferably, the feed antenna is a rectangular microstrip antenna.

[0012] Preferably, the partial reflective surface is fixed to the dielectric substrate by a plastic pillar.

[0013] Preferably, the dielectric substrate is a square substrate, and the plastic pillars are distributed at the four corners of the dielectric substrate.

[0014] Preferably, the first dielectric layer and the second dielectric layer are made of Jiantao KB6160 material with a relative permittivity of 4.6, and the dielectric substrate is made of FSD220D material with a relative permittivity of 2.2.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0016] This invention designs a metasurface with an adhesive dielectric layer that can effectively transmit and reflect electromagnetic waves, and uses it as a partial reflecting surface of a Fabry-Perot resonant cavity antenna. By optimizing the characteristics of the partial reflecting surface, electromagnetic waves can be enhanced in front of the antenna, thereby improving the antenna's radiation efficiency and directivity. High gain and broadband effect are achieved through multiple partial reflections and transmissions of electromagnetic waves in the Fabry-Perot resonant cavity antenna.

[0017] The antenna of this invention features simple structure, simple power supply, low processing difficulty, and low cost. Ultimately, the antenna of this invention has a relative bandwidth of 21.7% (16.09-20.02GHz), a gain higher than 13.18dBi in the operating frequency band, a peak gain of 16.3dBi, and a 3dB gain bandwidth of 15.68-19.96GHz (24%), accounting for 98.5% of the operating bandwidth. This antenna can maintain high gain in the operating frequency band. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a high-gain broadband Fabry-Perot resonant cavity antenna in an example of the present invention.

[0019] Figure 2a This is one of the structural schematic diagrams of a portion of the reflective surface in an example of the present invention.

[0020] Figure 2b This is the second schematic diagram of the structure of a portion of the reflective surface in an example of the present invention.

[0021] Figure 3 This is a schematic diagram of the structure of some of the reflective units in an example of the present invention.

[0022] Figure 4 This is a schematic diagram of the structure of the first metal layer in an example of the present invention.

[0023] Figure 5 This is a schematic diagram of the structure of the second metal layer in an example of the present invention.

[0024] Figure 6 This is a schematic diagram of the structure of the third metal layer in an example of the present invention.

[0025] Figure 7 This is a schematic diagram of the feed antenna structure in an example of the present invention.

[0026] Figure 8 This is a graph showing the S11 reflection coefficient and gain results of a high-gain broadband Fabry-Perot resonant cavity antenna in an example of the present invention.

[0027] Figure 9 These are the radiation patterns of the high-gain broadband Fabry-Perot resonator antenna at 16.5 GHz, 17.5 GHz, and 18.5 GHz in this embodiment of the invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0030] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have the transmission of electrical signals or data between them.

[0031] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Furthermore, the terms used in this specification include any and all combinations of the associated listed items.

[0032] like Figures 1 to 7As shown, this embodiment discloses a high-gain broadband Fabry-Perot resonant cavity antenna, including: a metal ground plane 8, a dielectric substrate 7, a feed antenna 9, a coaxial cable 11, and a partial reflector. The metal ground plane 8 is disposed on the lower surface of the dielectric substrate 7, the feed antenna 9 is disposed at the center of the upper surface of the dielectric substrate 7, the coaxial cable 11 passes through the dielectric substrate 7 and is connected to the feed antenna 9, and the partial reflector is disposed directly above the feed antenna 9, forming an air cavity 12 between the partial reflector and the feed antenna 9. The partial reflector is designed as a metasurface with an adhered dielectric layer, which can effectively transmit and reflect electromagnetic waves. When the feed antenna 9 emits electromagnetic waves, the partial reflector allows a portion of the electromagnetic waves to be reflected back into the resonant cavity, while allowing another portion of the electromagnetic waves to propagate through the metasurface. This allows the electromagnetic waves to be reflected multiple times within the resonant cavity, enhancing the electromagnetic field of a specific wavelength and achieving a high-gain broadband effect. By adjusting the distance between the partial reflector and the metal ground plane 8, the reflection and interference of electromagnetic waves can be optimized, thereby improving the antenna's directivity and gain.

[0033] Specifically, the partial reflective surface is composed of 8×8 adjacent partial reflective units, each unit measuring 5mm×5mm. Each partial reflective unit comprises, from top to bottom, a first metal layer 1, a first dielectric layer 2, a second metal layer 3, a second dielectric layer 5, and a third metal layer 6, stacked sequentially. The first dielectric layer 2 and the second dielectric layer 5 are bonded together, both being square in size. The first metal layer 1 and the second metal layer 3 are both chamfered rectangular metal patches, defined as first chamfered rectangular metal patches and second chamfered rectangular metal patches, respectively located at the center of the upper and lower surfaces of the first dielectric layer 2. The third metal layer 6 is a square metal patch covering the second dielectric layer 5. The four corners of the metal patch are loaded with L-shaped grooves, and the center is loaded with a cross-shaped groove symmetrical about the center and a large-sized chamfered rectangular groove, which integrates a small-sized chamfered rectangular metal patch. The chamfers of the first chamfered rectangular metal patch, the second chamfered rectangular metal patch, the large-sized chamfered rectangular groove and the small-sized chamfered rectangular metal patch are on the same diagonal in the same direction, and the length of the chamfers is consistent. In the figure, q is 0.3535mm. From top to bottom, the size of the first chamfered rectangular metal patch, the second chamfered rectangular metal patch and the small-sized chamfered rectangular metal patch increases and then decreases. The large-sized chamfered rectangle of the second chamfered rectangular metal patch provides a phase reflection superposition effect for electromagnetic waves.

[0034] Specifically, the feed antenna 9 is a rectangular microstrip antenna, fed by a coaxial cable 11. Its feed endpoint 10 is located slightly to the right of the horizontal line of the feed antenna 9. The feed antenna 9 adopts the simplest coaxial feeding method, which is simple in structure and easy to operate, but has a narrow bandwidth. The S-parameters of the feed antenna 9 are less than -10dB in the 15.66-17.37GHz range, with a relative bandwidth of 10.4%. It should be noted that the feed antenna 9 has a U-shaped slot 13 on one side near the feed endpoint 10, which is used to increase the electrical length of the metal patch on part of the reflector and adjust the capacitance and inductance of the antenna, so that the feed antenna 9 adds a resonant point at high frequencies and broadens the antenna bandwidth.

[0035] Specifically, the dielectric substrate 7 is a square substrate, and the partial reflective surface is fixed to the dielectric substrate 7 by plastic pillars 4 at the four corners.

[0036] Specifically, the first dielectric layer 2 and the second dielectric layer 5 are made of Jiantao KB6160, with a relative permittivity of 4.6 and dimensions of 40mm×40mm×1mm; the metal ground plane 8 has dimensions of 40mm×40mm; the air cavity 12 has a thickness of 8.8mm; the partial reflective surface has dimensions of 40mm×40mm; and the dielectric substrate 7 is made of FSD220D, with a relative permittivity of 2.2 and dimensions of 40mm×40mm×0.762mm.

[0037] like Figure 8 As shown in the figure, the design example obtained by optimizing the partial reflector surface and parameters of the Fabry-Perot resonant cavity antenna achieves an impedance bandwidth of 16.09-20.02 GHz and a relative bandwidth of 21.7%. Traditional rectangular microstrip antennas have low gain; the feed antenna in this example has a gain of around 6 dBi. In contrast, the Fabry-Perot resonant cavity antenna of this invention achieves a gain higher than 13.18 dBi across the operating frequency band, more than doubling the gain. The peak gain reaches 16.3 dBi, and the 3 dB gain bandwidth is 15.7-19.87 GHz (24%). The overlap between S11 and the 3 dB gain bandwidth is high, reaching 98.5%, achieving both wide bandwidth and stable gain.

[0038] like Figure 9 As shown, the radiation patterns of the Fabry-Perot resonant cavity antenna described in this embodiment are displayed at 16.5 GHz, 17.5 GHz, and 18.5 GHz. It can be seen from the figure that the antenna of this invention exhibits stable radiation within its operating range, with good directivity and high symmetry. The advantages of its good radiation characteristics are due to the structure of the Fabry-Perot resonant cavity antenna and its specific partial reflective surface.

[0039] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A high-gain broadband Fabry-Perot resonant cavity antenna, characterized in that, include: The device comprises a metal ground plane (8), a dielectric substrate (7), a feed antenna (9), a coaxial cable (11), and a partial reflective surface; wherein the metal ground plane (8) is disposed on the lower surface of the dielectric substrate (7), the feed antenna (9) is disposed at the center of the upper surface of the dielectric substrate (7), the coaxial cable (11) passes through the dielectric substrate (7) and is connected to the feed antenna (9), the partial reflective surface is disposed directly above the feed antenna (9) and forms an air cavity (12) between the feed antenna (9), the partial reflective surface is a metasurface with an adhesive dielectric layer, which can effectively transmit and reflect electromagnetic waves. When the feed antenna (9) emits electromagnetic waves, the partial reflective surface allows a portion of the electromagnetic waves to be reflected back to the resonant cavity, while allowing another portion of the electromagnetic waves to propagate through the metasurface, so that the electromagnetic waves can be reflected multiple times in the resonant cavity, enhancing the electromagnetic field of a specific wavelength and achieving a high-gain broadband effect; The partially reflective surface is composed of n×n adjacent partially reflective units, where n is an integer greater than or equal to 2. Each partially reflective unit includes a first metal layer (1), a first dielectric layer (2), a second metal layer (3), a second dielectric layer (5), and a third metal layer (6) stacked sequentially from top to bottom. The first dielectric layer (2) and the second dielectric layer (5) are bonded together, and both are square with the same size. The first metal layer (1) and the second metal layer (3) are both chamfered rectangular metal patches, defined as the first chamfered rectangular metal patch and the second chamfered rectangular metal patch. They are located at the center of the upper and lower surfaces of the first dielectric layer (2), respectively. The third metal layer (6) is a layer that covers the second dielectric layer. The square metal patch of the material layer (5) has L-shaped grooves loaded at its four corners, a cross-shaped groove symmetrical about the center and a large-sized chamfered rectangular groove in the middle, and a small-sized chamfered rectangular metal patch integrated therein. The chamfers of the first chamfered rectangular metal patch, the second chamfered rectangular metal patch, the large-sized chamfered rectangular groove and the small-sized chamfered rectangular metal patch are on the same diagonal in the same direction, and the length of the chamfers is consistent. From top to bottom, the size of the first chamfered rectangular metal patch, the second chamfered rectangular metal patch and the small-sized chamfered rectangular metal patch increases and then decreases. The large-sized chamfered rectangle of the second chamfered rectangular metal patch provides a phase reflection superposition effect for electromagnetic waves.

2. The high-gain broadband Fabry-Perot resonant cavity antenna according to claim 1, characterized in that, By adjusting the distance between the partial reflective surface and the metal ground plane (8), the reflection and interference of electromagnetic waves can be optimized.

3. A high-gain broadband Fabry-Perot resonant cavity antenna according to claim 1, characterized in that, The feed antenna (9) is fed by a coaxial cable (11), and a U-shaped groove (13) is opened on one side near the feed end point (10) to increase the electrical length of the metal patch of part of the reflective surface and adjust the capacitance and inductance of the antenna, so that the feed antenna (9) adds a resonant point at high frequency and widens the antenna bandwidth.

4. A high-gain broadband Fabry-Perot resonant cavity antenna according to claim 3, characterized in that, The feed antenna (9) is a rectangular microstrip antenna.

5. A high-gain broadband Fabry-Perot resonant cavity antenna according to claim 1, characterized in that, The partial reflective surface is fixed to the dielectric substrate (7) by plastic pillars (4).

6. A high-gain broadband Fabry-Perot resonant cavity antenna according to claim 5, characterized in that, The dielectric substrate (7) is a square substrate, and the plastic pillars (4) are distributed at the four corners of the dielectric substrate (7).

7. A high-gain broadband Fabry-Perot resonant cavity antenna according to claim 1, characterized in that, The first dielectric layer (2) and the second dielectric layer (5) are made of Jiantao KB6160 material with a relative permittivity of 4.6, and the dielectric substrate (7) is made of FSD220D material with a relative permittivity of 2.2.

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