A low-profile high-gain filtering antenna based on a center-symmetrical parasitic patch structure

Abstract

The application discloses a kind of low profile high gain filter antennas based on center-symmetric parasitic patch structure, belong to the antenna technical field of wireless communication, it includes from top to bottom sequentially arranged radiation network, F4B dielectric plate and metal floor;Radiation network is located dielectric plate upper surface, is made of driving patch, two parasitic patches connected with the driving patch, and four parasitic patches that are centrally symmetrically distributed around driving patch;Two metal ground columns are embedded in dielectric plate, and the two ends are respectively connected with radiation network and metal floor;Coaxial feed SMA connector inner conductor passes through metal floor and dielectric plate and is connected with center rhombus driving patch, outer conductor connects metal floor.The application is single-layer low profile structure, without additional filter circuit, with the advantages of simple structure, easy processing test.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology for wireless communication, and relates to a low-profile, high-gain filtering antenna based on a centrally symmetric parasitic patch structure. It is mainly used as a highly integrated radio frequency front-end device for short-range wireless transmission communication. Background Technology

[0002] With the rapid development of technologies such as wireless communication, the Internet of Things (IoT), and satellite communication, the performance requirements for antenna systems are constantly increasing. These requirements include high gain, wide coverage, low profile structure, excellent radiation efficiency, and selective control of the operating frequency band. Especially with the miniaturization trend in modern communication equipment, antennas not only need to meet high-performance radiation requirements but also need to be highly integrated with other RF modules to reduce system complexity and improve spectrum utilization efficiency. Against this backdrop, antennas with filtering characteristics have emerged, making filtered antennas a research hotspot. These antennas directly introduce filtering functionality into their radiating structure, thereby suppressing out-of-band spurious signals and improving signal purity without relying on external bandpass filters.

[0003] While traditional microstrip antenna structures offer advantages such as simplicity, ease of fabrication, and low cost, their inherent limitations are also significant. Firstly, to maintain antenna resonance, the profile height of conventional patch antennas is typically limited by the substrate's dielectric constant and thickness, making ultra-low profile designs difficult to achieve. Secondly, conventional radiating patches primarily radiate energy and lack frequency selectivity; their radiation frequency bands are usually quite broad, lacking effective out-of-band suppression. When systems require strict spectrum control, reduced subharmonic interference, or a reduction in the number of pre-stage filters, traditional structures often fall short.

[0004] To meet the demands for high performance and high integration, researchers have proposed various integrated filtering antenna schemes, including: adding LC filter structures to the antenna feed network; loading slot structures on radiating patches or ground planes to generate specific resonant modes; and using resonant ring structures or impedance transformation structures to form specific transmission zeros. However, these schemes generally suffer from problems such as complex structures, high requirements for manufacturing precision, limited bandwidth, and adverse effects on antenna radiation modes.

[0005] Antennas based on centrosymmetric structures can not only achieve dual-mode or multi-mode resonance by constructing equidistant coupling paths, but also enhance specific resonant modes by utilizing the mirror characteristics of current, thereby forming a bandpass characteristic with significant selectivity in the target frequency band. Simultaneously, the centrosymmetric structure can incorporate parasitic impedance paths under geometric control, allowing transmission nulls to be naturally generated out-of-band, effectively suppressing energy in non-operating frequency bands.

[0006] In summary, as communication systems trend towards miniaturization and multifunctionality, an antenna that combines low profile, high gain, and filtering capabilities with a centrally symmetrical structure has extremely high application value. It not only meets the requirements of modern wireless systems for high efficiency and high-selectivity spectral response but also provides a new structural reference for the integrated design of antennas and filters. Therefore, research on this type of antenna structure has significant theoretical implications and promising engineering applications. Summary of the Invention

[0007] To address the problems existing in the background art, this invention discloses a low-profile high-gain filtering antenna based on a centrally symmetric parasitic patch structure to achieve bandpass filtering function between 2.20 GHz and 2.56 GHz.

[0008] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0009] A low-profile, high-gain filter antenna based on a centrosymmetric parasitic patch structure includes a dielectric substrate; the upper surface of the dielectric substrate is provided with a radiating network, and the lower surface has a metal ground plane; the radiating network includes a driving patch, a symbiotic patch, and a parasitic patch;

[0010] The driving patch is located at the center of the dielectric substrate and has a rhomboid structure; there are two symbiotic patches, which are respectively connected to the two corners of the driving patch and are located on the same straight line; there are four parasitic patches, all of which are rectangular structures; the four parasitic patches correspond one-to-one with the four sides of the driving patch and are respectively located on the outside of the corresponding side of the driving patch.

[0011] The dielectric substrate has two metal grounding posts; the top of each metal grounding post is connected to the drive patch, and the bottom is connected to the metal ground plate.

[0012] Furthermore, the edge of the driving patch forms a 45° angle with the edge of the dielectric substrate.

[0013] Furthermore, the angle between the straight line containing the two symbiotic patches and the rhombus structure is 135°.

[0014] Furthermore, it also includes a coaxial-fed SMA connector, wherein the inner conductor of the coaxial-fed SMA connector passes through the metal ground plane and the dielectric substrate and is connected to the drive patch, and the outer conductor is connected to the metal ground plane.

[0015] The inner conductor of the coaxial-fed SMA connector is not in contact with the metal ground plane.

[0016] Furthermore, the symbiotic patch and the driving patch are integrated into one structure, with the two symbiotic patches symmetrically distributed along the diagonal of the driving patch.

[0017] Furthermore, the parasitic patch is arranged parallel to the edge of the driving patch.

[0018] Furthermore, the dielectric substrate is made of F4B material, with a dielectric constant of 2.65 and a loss tangent of 0.003.

[0019] Furthermore, both the radiation network and the metal floor are made of copper with a thickness of 0.0254 mm.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] a) The antenna has a low profile. The F4B high-frequency board is used as the dielectric board. A metal ground plane is set on one side of the dielectric board and a radiating network is set on the other side of the dielectric board. The radiating network consists of a driving patch, a symbiotic patch and four parasitic patches that are centrally symmetrical. The antenna is fed through a coaxial probe SMA. A radiation null is introduced through the electromagnetic coupling between the driving patch and the parasitic patch to form a bandpass filter response. The antenna structure is simple and easy to process and test.

[0022] (b) The parasitic patch structure of the present invention provides a filter antenna with a wider bandwidth and higher average gain. After fabrication and verification, the antenna achieves a bandwidth of 15.1% (2.2-2.56 GHz) and an average gain of 6.88 dBi within the passband.

[0023] c) The filter antenna with parasitic patch of the present invention has a smaller in-band flatness and a steeper edge selectivity in the passband, with low / high frequency edge selectivity reaching 186.67 / 207.5 dB / GHz.

[0024] d) The filter antenna with parasitic patch of the present invention has a low profile, small size, simple structure, and does not require an additional filter circuit structure, making it easy to manufacture. Using F4B as the dielectric substrate, the antenna's profile height is 0.031. ( (The wavelength in vacuum corresponding to the center frequency of the antenna) has a low profile and a single-layer structure, making it easier to process. The feeding structure is achieved by coaxial feeding, which is simple to manufacture. Attached Figure Description

[0025] Figure 1 This is an overall structural diagram of an embodiment of the present invention;

[0026] Figure 2 This is a top view of an embodiment of the present invention;

[0027] Figure 3 This is a side view of an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the dimensional parameters of an embodiment of the present invention;

[0029] Figure 5 The graphs show the simulation and measured results of S11 and gain in an embodiment of the present invention.

[0030] Figure 6 This is an embodiment of the present invention. E-plane orientation pattern at that time;

[0031] Figure 7 This is an embodiment of the present invention. H-plane orientation pattern at time;

[0032] Figure 8 This is an embodiment of the present invention. E-direction pattern at time;

[0033] Figure 9 This is an embodiment of the present invention. H-direction pattern at time;

[0034] Figure 10 This is an embodiment of the present invention. E-plane orientation pattern at that time;

[0035] Figure 11 This is an embodiment of the present invention. H-plane orientation pattern at time;

[0036] Figure 12 This is an efficiency diagram of an embodiment of the present invention;

[0037] Figure 13 This is an embodiment of the present invention. Surface current diagram at time;

[0038] Figure 14 This is an embodiment of the present invention. Surface current diagram at time.

[0039] In the diagram: 1234, parasitic patch; 1, parasitic patch a; 2, parasitic patch b; 3, parasitic patch c; 4, parasitic patch d; 5, driver patch; 67, symbiotic patch; 6, symbiotic patch a; 7, symbiotic patch b; 8, metal grounding post a; 9, metal grounding post b; 10, coaxial feed SMA connector; 11, dielectric substrate; 12, metal grounding plate. Detailed Implementation

[0040] The technical solution of the present invention will now be described in detail and completely with reference to the accompanying drawings. It should be noted that the described embodiments are merely one specific implementation of the present invention, used to help understand the technical concept of the present invention, and do not constitute a limitation on the scope of protection of the present invention.

[0041] like Figures 1 to 3As shown, this embodiment provides a low-profile, high-gain filter antenna based on a centrally symmetric parasitic patch structure, with a center operating frequency of 2.38 GHz. The antenna is a single-layer planar structure, comprising a radiating network, a dielectric substrate 11, and a metal ground plane 12 arranged sequentially from top to bottom. The radiating network is located on the upper surface of the dielectric substrate 11, and the metal ground plane 12 is located on the lower surface of the dielectric substrate 11.

[0042] The radiation network consists of a driving patch 5, symbiotic patches a6 and b7, and parasitic patches a1, b2, c3, and d4. The driving patch 5 is located in the central region of the dielectric substrate 11 and has a rhomboid structure, with its four sides forming a 45° angle with the edge of the dielectric substrate 11. Symbiotic patches a6 and b7 are rectangular structures, respectively connected to the two opposite corners of the driving patch 5 and symmetrically distributed along the diagonals of the driving patch 5, both located on the same straight line. This straight line forms a 135° angle with the side of the rhomboid driving patch. Parasitic patches a1, b2, c3, and d4 are all rectangular structures, respectively positioned on the outer side of the four sides of the driving patch 5 and arranged parallel to their corresponding sides, exhibiting a centrally symmetrical distribution.

[0043] To enhance the antenna's bandwidth and edge selectivity, this embodiment embeds metal grounding posts a8 and b9 within the dielectric substrate 11. The upper ends of metal grounding posts a8 and b9 are connected to both sides of the driving patch 5, respectively, and the lower ends are connected to the metal ground plane 12, achieving short-circuit grounding of the driving patch 5 and thus optimizing the current distribution path. In this embodiment, the upper ends of the two metal grounding posts are located on the straight line where the symbiotic patch 67 is located.

[0044] The antenna is fed through a coaxial feed SMA connector 10. The inner conductor of the coaxial feed SMA connector 10 passes through the metal ground plane 12 and the dielectric substrate 11 and is electrically connected to the drive patch 5, while the outer conductor is electrically connected to the metal ground plane 12. The inner conductor remains insulated from the metal ground plane 12 during its passage.

[0045] The driver patch 5 is connected to the probe of the coaxial feed SMA connector 10 to provide an intermediate frequency point. The two symbiotic patches 67 loaded on both sides of the driver patch 5 can excite a low-frequency resonant point within a band. And as Figure 13 As shown, the two co-existing patches 67 excite opposite currents along the ±x directions, and their energies are almost equal, canceling each other out, thus producing an out-of-band radiation zero. In addition, four centrally symmetrical parasitic patches 1234 are introduced around the periphery, such as... Figure 14As shown, the current generated by the excitation on the four parasitic patches 1234 is distributed along the direction of the black diagonal arrows in the figure. After decomposing the current of each parasitic patch 1234 into x-axis and y-axis components, it can be seen that the x-axis current components of the four parasitic patches 1234 are arranged symmetrically in opposite directions, thus canceling out the total current in the x-direction. The y-axis current components of all parasitic patches 1234 uniformly point towards the negative y-axis, forming a superimposed negative y-axis current. Simultaneously, the current generated by the excitation on the driving patch 5 mainly points towards the positive y-axis, and its energy is approximately equal to the energy of the negative y-axis current formed by the superposition of the parasitic patches 1234, causing the total current in the y-direction to also cancel out. Therefore, through the above-mentioned dual cancellation mechanism of x and y-direction currents, an additional resonant frequency point is introduced within the operating frequency band. And form an out-of-band radiation null in the high-frequency band. This optimizes the frequency response characteristics of the antenna. Figure 13 and Figure 14 In the diagram, red, brown, orange, yellow, green, and blue arrows all represent current intensity, with the current intensity decreasing in that order; the black arrow indicates the direction of the overall current.

[0046] The two metal grounding posts embedded in the dielectric substrate 11 short-circuit the driving patch 5 to the ground, thereby improving the current path on the patch surface and enabling the filter antenna to obtain a wider bandwidth and a steeper edge selectivity.

[0047] In this embodiment, the dielectric substrate 11 is made of "F4B" material, with a dielectric constant of 2.65, a loss tangent of 0.003, and a thickness of 4mm.

[0048] according to Figure 4 The structural parameters shown are illustrated in Table 1, where the thickness of the dielectric substrate is h.

[0049] Table 1: Antenna Parameter Table

[0050]

[0051] After adjusting the dimensional parameters of this embodiment, the embodiment was verified through electromagnetic field simulation, fabrication, and testing in a darkroom. Figure 5As shown, the simulation and physical test results of the antenna's S11 and gain parameters in the 1.75-3GHz frequency range are compared. The figure shows four curves: red for S11, blue for gain, solid lines for simulation values, and dashed lines for test results. It can be seen that the measured impedance bandwidth of the antenna is 15.1% (2.2-2.56GHz), slightly wider than the simulation result of 14.8% (2.19-2.54GHz). The in-band S11 parameter is relatively flat, and it exhibits steep edge selectivity (186.67dB / GHz, 207.5dB / GHz). The maximum measured gain of the antenna within the bandwidth is 7.48dBi (achieved at 2.21GHz), and the average in-band gain is 6.88dBi. The two radiation nulls are 2.06GHz and 2.64GHz, respectively. The comparison between simulation and measurement shows good consistency; the slight error is mainly caused by manufacturing tolerances and the testing environment.

[0052] This embodiment is in The orientation patterns of the E-plane and H-plane are as follows Figure 6 and Figure 7 As shown, the solid line represents the simulated value, and the dashed line represents the measured result.

[0053] This embodiment is in The orientation patterns of the E-plane and H-plane are as follows Figure 8 and Figure 9 As shown, the solid line represents the simulated value, and the dashed line represents the measured result.

[0054] This embodiment is in The orientation patterns of the E-plane and H-plane are as follows Figure 10 and Figure 11 As shown, the solid line represents the simulated value, and the dashed line represents the measured result.

[0055] The efficiency of this embodiment is as follows: Figure 12 As shown, the solid line represents the simulated value, and the dashed line represents the measured result.

[0056] The above description represents the preferred embodiments of the present invention. It should be noted that, without departing from the principles of the present invention, those skilled in the art can adjust different parameters according to specific embodiments, or make equivalent substitutions or changes according to the technical solutions of the present invention. These improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A low-profile, high-gain filter antenna based on a centrosymmetric parasitic patch structure, comprising a dielectric substrate (11); the upper surface of the dielectric substrate (11) is provided with a radiating network, and the lower surface has a metal ground plane (12); characterized in that, The radiation network includes a driving patch (5), a symbiotic patch, and a parasitic patch; The driving patch (5) is located at the center of the dielectric substrate (11) and has a rhomboid structure. There are two symbiotic patches, which are respectively connected to the two opposite corners of the driving patch (5) and the two symbiotic patches are located on the same straight line. There are four parasitic patches, all of which have a rectangular structure. The four parasitic patches correspond one-to-one with the four sides of the driving patch (5) and are respectively located on the outside of the corresponding side of the driving patch (5). The long side of each parasitic patch is parallel to the corresponding side of the driving patch (5). The two symbiotic patches and the four parasitic patches do not overlap in position; The dielectric plate (11) has two metal grounding posts; the upper ends of metal grounding post a (8) and metal grounding post b (9) are connected to the two sides of the driving patch (5) respectively, and the lower ends are connected to the metal ground plate (12).

2. The low-profile high-gain filter antenna based on a centrally symmetric parasitic patch structure according to claim 1, characterized in that, The edge of the driving patch (5) forms a 45° angle with the edge of the dielectric substrate (11).

3. The low-profile high-gain filter antenna based on a centrally symmetric parasitic patch structure according to claim 1, characterized in that, The angle between the line containing the two symbiotic patches and the side of the rhombus structure is 135°.

4. The low-profile high-gain filter antenna based on a centrally symmetric parasitic patch structure according to claim 1, characterized in that, It also includes a coaxial feed SMA connector (10), the inner conductor of which passes through the metal ground plate (12) and the dielectric plate (11) and is connected to the drive patch (5), and the outer conductor is connected to the metal ground plate (12). The inner conductor of the coaxial-fed SMA connector (10) is not in contact with the metal ground plane (12).

5. A low-profile, high-gain filter antenna based on a centrally symmetric parasitic patch structure according to claim 1, characterized in that, The symbiotic patch (6,7) and the driving patch (5) are an integral structure, and the two symbiotic patches (6,7) are symmetrically distributed along the diagonal of the driving patch (5).

6. The low-profile high-gain filter antenna based on a centrally symmetric parasitic patch structure according to claim 1, characterized in that, The parasitic patch is set parallel to the edge of the driving patch (5).

7. A low-profile, high-gain filter antenna based on a centrally symmetric parasitic patch structure according to claim 1, characterized in that, The dielectric substrate (11) is made of F4B material with a dielectric constant of 2.65 and a loss tangent of 0.

003.

8. A low-profile, high-gain filter antenna based on a centrally symmetric parasitic patch structure according to claim 1, characterized in that, Both the radiation network and the metal floor (12) are made of copper and have a thickness of 0.0254 mm.

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