An antenna gain amplifier based on the principle of Fabry-Perot resonator

Abstract

The application provides an antenna gain amplifier based on a Fabry-Perot resonant cavity principle, comprising upper and lower dielectric substrates arranged in parallel and a feed antenna arranged below the lower dielectric substrate; the lower surface of the upper dielectric substrate is provided with a periodic metal patch, and the upper dielectric substrate and the metal patch jointly form a partial reflection surface; the lower dielectric substrate is composed of a periodically arranged unit structure, the unit structure comprises a base layer and a first dielectric and a second dielectric arranged on the upper surface of the base layer, and the first dielectric and the second dielectric are symmetrically arranged at both ends of the center line of the base layer; the periodically arranged unit structure forms a non-reciprocal metasurface. The antenna gain amplifier based on the Fabry-Perot resonant cavity principle can solve the problem that, in the prior art, after the direction or phase requirement of the FP resonant cavity antenna changes, the original antenna cannot be recycled, resulting in a large amount of resource waste.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to an antenna gain amplifier based on the Fabry-Perot resonator principle. Background Technology

[0002] Antennas are a crucial component in wireless communication systems, responsible for transmitting and receiving electromagnetic signals. In the context of rapid advancements in wireless communication technology, multifunctional antennas that simultaneously possess high gain, low cost, and simple structure have broad application prospects and have thus attracted widespread attention and research. FP resonant cavity antennas (short for Fabry-Perot resonant cavity antennas, also known as Fabry-Perot resonant cavity antennas) generally consist of two parallel dielectric substrates and a feed antenna placed on the upper surface of the lower dielectric substrate. When the resonance condition is met, electromagnetic waves are reflected and transmitted multiple times within the cavity before being fully radiated out of the cavity and superimposed in phase outside the cavity. They possess significant advantages such as simple structure, high gain, low design difficulty, and the absence of complex feed networks, making them widely used in the field of wireless communication.

[0003] Traditional FP (Functional Population) resonator antennas typically use a total internal reflection metal ground plane as the lower dielectric substrate, while the antenna feed is usually placed inside the cavity. This requires creating a groove on the upper surface of the lower dielectric substrate and then embedding the antenna feed within the groove. In this structure, the position of the feed antenna is relatively fixed and generally inseparable from the lower dielectric substrate; moreover, multiple feed antennas are usually arranged on the lower dielectric substrate to form an antenna array for gain. However, when requirements change, such as a change in the desired radiation direction or phase, a new FP resonator antenna must be redesigned and manufactured. The original antenna cannot be recycled and is directly scrapped, resulting in significant resource waste. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide an antenna gain amplifier based on the Fabry-Perot resonator principle, which aims to solve at least one technical problem in the background art.

[0005] The antenna gain amplifier based on the Fabry-Perot resonator principle proposed in this invention includes an upper dielectric substrate, a lower dielectric substrate, and a feed antenna disposed below the lower dielectric substrate and away from the upper dielectric substrate, arranged in parallel. The lower surface of the upper dielectric substrate has periodic metal patches, which together form a reflective surface. The lower dielectric substrate is composed of periodically arranged unit structures, each unit structure including a substrate layer and a first dielectric and a second dielectric disposed on the upper surface of the substrate layer. The first dielectric and the second dielectric are symmetrically placed at both ends of the centerline of the substrate layer. The periodically arranged unit structures form a non-reciprocal metasurface. The partially reflective surface and the non-reciprocal metasurface constitute a Fabry-Perot resonator.

[0006] The aforementioned antenna gain amplifier based on the Fabry-Perot resonator principle constructs a resonator cavity using partially reflective surfaces and non-reciprocal metasurfaces placed parallel to each other at a certain distance. The feed antenna is positioned on the lower dielectric substrate outside the resonator cavity, away from the upper dielectric substrate. In practical use, electromagnetic waves emitted by the feed antenna enter the cavity through the non-reciprocal metasurfaces. The partially reflective surfaces allow some electromagnetic waves to pass through while reflecting another portion back into the cavity. This reflection is then repeated by the non-reciprocal metasurfaces. When the resonance condition is met, the electromagnetic waves undergo multiple transmissions and reflections within the cavity before exiting and can be superimposed in phase, thus enhancing the gain. Specifically, since the feed antenna is positioned below the lower dielectric substrate, changes in the required antenna radiation or phase can be achieved simply by adjusting the position of the feed antenna below the lower dielectric substrate, eliminating the need to redesign and manufacture a new Fabry-Perot resonator antenna and avoiding resource waste.

[0007] In addition, the antenna gain amplifier based on the Fabry-Perot resonator principle proposed in this invention may also have the following additional technical features:

[0008] Preferably, the first dielectric material is ferrite, the second dielectric material is ceramic, and the substrate material is plastic foam.

[0009] Preferably, the metal patch is a square annular patch.

[0010] Preferably, the feed antenna is a microstrip patch antenna.

[0011] Preferably, both the first dielectric and the second dielectric are cubic.

[0012] Preferably, the length of the first dielectric is 3.5 mm to 4.5 mm, and the length of the second dielectric is 1.9 mm to 2.1 mm.

[0013] Preferably, the outer ring length of the square annular patch is 7.1 mm to 8 mm, and the inner ring length is 4.4 mm to 5.5 mm.

[0014] Preferably, the resonance condition of the Fabry-Perot resonator is: Where f is the operating frequency, ω and , where h is the reflection phase of the upper dielectric substrate and the lower dielectric substrate, respectively; h is the cavity height; and N is any integer. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the antenna gain amplifier based on the Fabry-Perot resonator principle proposed in the first embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the unit structure of the partial reflective surface proposed in the first embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of the feed antenna structure proposed in the first embodiment of the present invention;

[0018] Figure 4 for Figure 3 A sectional view along direction A;

[0019] Figure 5 This is a schematic diagram of the unit structure of the lower dielectric substrate proposed in the first embodiment of the present invention;

[0020] Figure 6 This is a diagram showing the reflection and transmission coefficients of the lower dielectric substrate proposed in the first embodiment of the present invention;

[0021] Figure 7 This is a reflection amplitude and reflection phase diagram of the upper dielectric substrate proposed in the first embodiment of the present invention;

[0022] Figure 8 This is the S11 curve diagram of the feed antenna proposed in the first embodiment of the present invention;

[0023] Figure 9 The radiation pattern of the feed antenna proposed in the first embodiment of the present invention;

[0024] Figure 10 The radiation pattern of the antenna gain amplifier based on the Fabry-Perot resonator principle proposed in the first embodiment of the present invention;

[0025] Figure 11 The radiation pattern of the antenna gain amplifier based on the Fabry-Perot resonator principle proposed in the second embodiment of the present invention is shown.

[0026] Figure 12The radiation pattern of the antenna gain amplifier based on the Fabry-Perot resonator principle proposed in the third embodiment of the present invention is shown.

[0027] Explanation of key component symbols:

[0028] Upper dielectric substrate 10 Lower dielectric substrate 20 feed antenna 30 Metal patch 11 basal layer 21 First dielectric 22 Second dielectric 23 Substrate substrate 31 Top rectangular patch 32 Bottom rectangular patch 33 First columnar conductor 34 Second columnar conductor 35 Insulating ring 36

[0029] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0030] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0031] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0032] 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 invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] Please see Figures 1 to 10 The image shows an antenna gain amplifier based on the Fabry-Perot resonator principle in the first embodiment of the present invention, comprising an upper dielectric substrate 10 and a lower dielectric substrate 20 arranged in parallel, and a feed antenna 30 disposed below the lower dielectric substrate 20 and away from the upper dielectric substrate 10; wherein:

[0034] The lower surface of the upper dielectric substrate 10 is provided with periodic metal patches 11. The upper dielectric substrate 10 and the metal patches 11 together constitute a reflective surface. The lower dielectric substrate 20 is composed of periodically arranged unit structures. The unit structure includes a base layer 21 and a first dielectric 22 and a second dielectric 23 disposed on the upper surface of the base layer 21. The first dielectric 22 and the second dielectric 23 are symmetrically placed at both ends of the center line of the base layer 21. The periodically arranged unit structure forms a non-reciprocal metasurface. The aforementioned partial reflective surface and the aforementioned non-reciprocal metasurface constitute a Fabry-Perot resonant cavity.

[0035] Understandably, a resonant cavity is constructed by placing parallel reflective surfaces and non-reciprocal metasurfaces at a certain distance. The feed antenna 30 is positioned on the side of the lower dielectric substrate 20 outside the resonant cavity, away from the upper dielectric substrate 10. In practical use, electromagnetic waves irradiated by the feed antenna 30 enter the cavity through the non-reciprocal metasurface. The partial reflective surfaces allow some electromagnetic waves to be transmitted out, while reflecting some back into the cavity. These waves are then reflected back to the partial reflective surfaces by the non-reciprocal metasurface. When the resonance condition is met, the electromagnetic waves are transmitted and reflected multiple times within the cavity before exiting, and they can be superimposed in phase, thereby enhancing the gain. Specifically, since the feed antenna 30 is positioned below the lower dielectric substrate 20, when the required antenna radiation or phase changes, the position of the feed antenna 30 below the lower dielectric substrate 20 can be adjusted accordingly to meet the requirements, eliminating the need to redesign and manufacture a new FP resonant cavity antenna and avoiding resource waste.

[0036] It should be noted that the design of the metasurface is based on the principle of Fano resonance generated by the first dielectric 22 and the second dielectric 23. Fano resonance originates from the constructive and destructive coupling between the bright mode and the weak background. The cube of the second dielectric 23 exhibits strong Mie resonance near the Fano mode, while the first dielectric 22 generates a weak background. According to the classical Fano analogy theory, these two different components will cause Fano interference inside the structure, thereby destroying the time symmetry and realizing the unidirectional transmission of electromagnetic waves, i.e., non-reciprocity.

[0037] Furthermore, the first dielectric 22 is made of ferrite, the second dielectric 23 is made of ceramic, and the substrate 21 is made of plastic foam. The substrate 21 provides support for the first and second dielectrics; therefore, plastic foam is chosen for the substrate 21 because its dielectric constant is approximately the same as air and will not affect the propagation of electromagnetic waves. Ferrite is chosen for the first dielectric 22 because the magnetic properties of magnetically biased ferrite at microwave frequencies are closely related to the applied magnetic field. Ceramic is chosen for the second dielectric 23 because its dielectric constant can be varied, and different high dielectric constants can be obtained through adjustment; that is, the parameters of both can be adjusted, making it easier for software simulation to obtain the optimal non-reciprocal metasurface parameters.

[0038] Additionally, the metal patch 11 is a square annular patch. The square annular patch enables electromagnetic waves to be transmitted through the slotted portion in the middle of the patch, and some electromagnetic waves are reflected back into the cavity through the solid portion of the patch.

[0039] It needs to be explained that, This formula defines the resonance condition for an FP resonant cavity, and the cavity design is based on this formula. Where f is the operating frequency, ω, and... Here, h represents the reflection phases of the upper and lower dielectric substrates, respectively, h is the cavity height, and N is an integer. Therefore, when designing a partial reflective coating operating at dual frequencies, it is necessary to first determine the operating frequency, then the cavity height, and finally design the phase of the partial reflective coating to satisfy… The phase of the underlying dielectric substrate is generally π, and the formula simplifies to: When the dual-frequency operating points are 5GHz and 10GHz, according to the formula, it can be calculated that the phase of the upper dielectric substrate only needs to be designed to be π at 10GHz and 0 at 5GHz, and the cavity height is 15mm.

[0040] Please see Figures 6 to 8 The above describes the specific parameters of an antenna gain amplifier based on the Fabry-Perot resonator principle according to an embodiment of the present invention, and the gain effect of the gain amplifier on the antenna. Specifically, it describes the specific parameters of each component when the resonator height is 15mm and the operating frequency is 10GHz.

[0041] Specifically, the length and width of the periodic unit structure of the partial reflective surface are both P = 8.1 mm, including the upper dielectric substrate 10 and the bottom etched square ring metal patch 11. The outer ring length is m = 7.9 mm and the inner ring length is 4.5 mm. The upper dielectric substrate 10 is a Rogers RO4003C dielectric substrate with a thickness of 1 mm. It is worth noting that, for some reflective surface unit structures, when the length and width remain the same, the reflection phase and amplitude do not change significantly when the value of P is between 7.5-10.5mm or even larger. Considering the requirements of antenna miniaturization, structural simplicity, and performance, P is set to 8.1mm. When the length of the square outer ring is in the range of 7.1-8mm, there is a slow phase lag (-169° to -182°). Similarly, when the length of the square inner ring varies from 4.4-5.5mm, the phase also lags slowly (-175° to -187°). The reflection amplitude decreases as the coverage area of ​​the square ring decreases. Therefore, the phase requirement of -180° can be achieved within the aforementioned range. In this example, considering both phase and amplitude requirements, the outer ring length is set to m = 7.9mm, and the inner ring length is set to 4.5mm. Figure 7 As shown, with this configuration, the upper dielectric substrate 10 achieves a reflection phase of -180° at 10 GHz, which is the required reflection phase of π at 10 GHz, while maintaining a high reflection amplitude, close to 1, to ensure antenna gain. It should be noted that generally, the closer the amplitude is to 1, the better the antenna gain.

[0042] Furthermore, the feed antenna is a microstrip patch antenna. Specifically, in some optional embodiments, the microstrip patch antenna has a bottom dielectric ground plane 31, a top rectangular patch 32 disposed above the bottom dielectric ground plane 31, and a bottom rectangular patch 33 covering the bottom dielectric ground plane 31. A first columnar conductor 34 penetrates the bottom dielectric ground plane 31, the top rectangular patch 32, and the bottom rectangular patch 33. A second columnar conductor 35 is sleeved outside the first columnar conductor 34 and separated by an insulating ring 36. After optimization, the thickness of the bottom dielectric ground plane 31 is 1mm, the relative permittivity is 2.2, the length l of the top rectangular patch 32 is 13.8mm, and the width w is 9mm, enabling it to operate well at the 10GHz operating frequency. Regarding the patch dimensions: the length l can control the feed antenna S... 11 The depth and width w can control the frequency offset. A depth of 13.6-14mm and a width of 8.9-9.2mm can meet the antenna design requirements and are all within the protection range of this example. For example... Figure 8 As shown, using this parameter, the reflection coefficient of the feed antenna 30 is the highest when the operating frequency is around 10GHz, and the performance of the feed antenna 30 is optimal at this time.

[0043] Furthermore, the first dielectric 22 is made of ferrite and is a cube with a length of 4 mm; the second dielectric 23 is made of ceramic and is a cube with a length of 2.03 mm. These dimensions are optimal parameters after software optimization; for example... Figure 6 With these parameters, when the non-reciprocal metasurface operates at a frequency of 10 GHz, the reflection coefficient of electromagnetic waves irradiating the non-reciprocal metasurface within the cavity is approximately 0.8, and the transmission coefficient of electromagnetic waves irradiated from the feed antenna through the non-reciprocal metasurface is approximately 0.6. Further references... Figure 9 and Figure 10 It can be seen that the maximum actual gain of the feed antenna in this embodiment of the invention is 8.1 dBi at 10 GHz. After being amplified by the antenna gain amplifier of the first embodiment of the invention, the maximum actual gain at the resonant operating frequency is 12.2 dBi, which shows a significant improvement in actual gain, demonstrating the feasibility of the design.

[0044] Please see Figure 11 The figure shows the radiation pattern of the antenna gain amplifier based on the Fabry-Perot resonator principle in the second embodiment of the present invention. The only difference between the second embodiment and the first embodiment is that the first dielectric is a ferrite cube with a side length of 3.5 mm, and the second dielectric is a ceramic cube with a variable length of 1.9 mm. At this time, the reflection coefficient of the non-reciprocal metasurface is 0.73, the transmission coefficient is 0.51, and the actual gain is 10.3 dBi.

[0045] Please see Figure 12 The figure shows the radiation pattern of the antenna gain amplifier based on the Fabry-Perot resonator principle in the third embodiment of the present invention. The only difference between the third embodiment and the first embodiment is that the first dielectric is a ferrite cube with a side length of 4.5 mm, and the second dielectric is a ceramic cube with a variable length of 2.1 mm. At this time, the reflection coefficient of the non-reciprocal metasurface is 0.65, the transmission coefficient is 0.45, and the actual gain is 9.4 dBi.

[0046] In addition, compared with the traditional Fabry-Perot resonant cavity antenna, the gain may not be outstanding. This is because the metasurface cannot completely prevent the electromagnetic waves irradiated from the feed from entering the cavity as ideally as possible. The electromagnetic waves reflected back from the upper part of the reflective surface cannot be completely reflected back into the cavity, so the energy loss is large and the performance is also reduced. There is still a lot of room for improvement in this design.

[0047] In summary, the antenna gain amplifier based on the Fabry-Perot resonator principle in the above embodiments of the present invention forms a resonator by placing parallel partially reflective surfaces and non-reciprocal metasurfaces at a certain distance. The feed antenna 30 is disposed on the side of the lower dielectric substrate 20 outside the resonator, away from the upper dielectric substrate 10. In specific use, electromagnetic waves irradiated by the feed antenna 30 enter the cavity through the non-reciprocal metasurface. The partially reflective surfaces allow some electromagnetic waves to be transmitted out, while reflecting some electromagnetic waves back into the cavity. These waves are then reflected back to the partially reflective surfaces by the non-reciprocal metasurfaces. When the resonance condition is met, the electromagnetic waves are transmitted and reflected multiple times within the cavity before being transmitted out of the cavity and can be superimposed in phase, thereby achieving the purpose of enhancing the gain. Specifically, since the feed antenna 30 is disposed below the lower dielectric substrate 20, when the required antenna radiation or phase changes, the position of the feed antenna 30 below the lower dielectric substrate 20 can be adjusted accordingly to meet the requirements, without the need to redesign and manufacture a new Fabry-Perot resonator antenna, thus avoiding resource waste.

[0048] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An antenna gain amplifier based on the Fabry-Perot resonator principle, characterized in that, The system includes an upper dielectric substrate and a lower dielectric substrate arranged in parallel, and a feed antenna disposed below the lower dielectric substrate and away from the upper dielectric substrate. The lower surface of the upper dielectric substrate has periodic metal patches, which together form a reflective surface. The lower dielectric substrate is composed of periodically arranged unit structures, each unit structure including a substrate layer and a first dielectric and a second dielectric disposed on the upper surface of the substrate layer. The first dielectric and the second dielectric are symmetrically placed at both ends of the centerline of the substrate layer. The periodically arranged unit structures form a non-reciprocal metasurface. The partially reflective surface and the non-reciprocal metasurface constitute a Fabry-Perot resonator. The first dielectric material is ferrite, the second dielectric material is ceramic, and the substrate material is plastic foam; The metal patch is a square ring-shaped patch; Both the first dielectric and the second dielectric are cubic.

2. The antenna gain amplifier based on the Fabry-Perot resonator principle according to claim 1, characterized in that, The feed antenna is a microstrip patch antenna.

3. The antenna gain amplifier based on the Fabry-Perot resonator principle according to claim 1, characterized in that, The length of the first dielectric is 3.5 mm to 4.5 mm, and the length of the second dielectric is 1.9 mm to 2.1 mm.

4. The antenna gain amplifier based on the Fabry-Perot resonator principle according to claim 1, characterized in that, The outer ring of the square annular patch has a length of 7.1 mm to 8 mm, and the inner ring has a length of 4.4 mm to 5.5 mm.

5. The antenna gain amplifier based on the Fabry-Perot resonator principle according to claim 1, characterized in that, The resonance condition of a Fabry-Perot resonator is Where f is the operating frequency, and , where h is the reflection phase of the upper dielectric substrate and the lower dielectric substrate, respectively; h is the cavity height; and N is any integer.

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