Multi-feed common-caliber patch antenna capable of realizing multi-sector controllable radiation

Abstract

The invention discloses a common-caliber multi-feed patch antenna structure capable of realizing controllable radiation patterns of multiple sectors. The common-caliber multi-feed patch antenna structure comprises a radiation patch, a dielectric substrate, a grounding layer and three feed ports, in order to realize omnidirectional (360-degree) radiation coverage on a horizontal plane and effectively suppress high coupling among the ports, the layout of the three feed ports is optimized, and a combined structure of a Y-shaped groove, an edge metal via hole and a patch outer ring is introduced, so that the isolation among the ports is effectively improved. Experiments show that the circular patch antenna structure can realize azimuth omnidirectional radiation, and the isolation degree between ports is higher than 14 dB. Compared with a standard patch antenna, the characteristic frequency deviation caused by the additional structure can be compensated by adjusting the size of the radiation patch. According to the invention, near 360-degree effective radiation coverage is realized through a plurality of sectors, high coupling between ports and miniaturization of an antenna array are effectively inhibited, and the antenna is suitable for the fields of indoor positioning, wireless sensing integrated systems and the like.

Description

Technical Field

[0001] This invention relates to the field of microwave technology, and more specifically, to a common-aperture multi-feed patch antenna structure for Wi-Fi indoor positioning. Background Technology

[0002] Patch antennas are widely used in modern wireless communication and sensing and positioning systems due to their advantages such as low profile, light weight, low cost, ease of manufacturing, and conformal integration with circuit boards.

[0003] However, arranging multiple densely packed feed ports within a limited space and feeding the same radiating patch can induce strong mutual coupling effects. This not only leads to antenna impedance mismatch and radiation pattern distortion, but also affects the stability of polarization characteristics, making it difficult to achieve the design goal of multi-port feeding.

[0004] Traditional single-fed patch antennas typically have a fixed radiation pattern and limited beamwidth, making it difficult to achieve 360° omnidirectional coverage in the horizontal plane. Although increasing the number of feed ports can create multiple radiation beams to extend the coverage area, integrating multiple ports onto the same radiating patch introduces severe inter-port coupling, leading to problems such as antenna performance degradation, pattern distortion, and decreased positioning accuracy. This has become a key technical bottleneck in the design of multi-fed antennas. Summary of the Invention

[0005] To address the limitations of existing single-fed patch antennas in terms of beam coverage, and the impedance mismatch, pattern distortion, and performance degradation caused by strong mutual coupling when multiple feed ports are integrated into the same radiating patch, this invention aims to provide an innovative common-aperture multi-fed patch antenna structure.

[0006] The specific objectives of this invention include: achieving near 360° effective radiation coverage in the horizontal plane through multi-port collaborative operation, overcoming the narrow beam limitation of traditional single-feed patch antennas. While integrating multiple feed ports within a limited aperture, the innovative structural design significantly reduces electromagnetic coupling between the ports. In the process of expanding coverage and improving isolation, the antenna maintains core performance characteristics such as good impedance matching and radiation efficiency.

[0007] To achieve the above-mentioned objectives, this invention provides a common-aperture multi-feed patch antenna structure capable of omnidirectional horizontal radiation. The structure, from top to bottom, mainly includes: a radiating patch, a dielectric substrate, and a ground layer; additional structures such as a "Y"-shaped slot, edge-metallized vias, and an outer ring of the patch are introduced; multiple feed ports are integrated on the radiating patch.

[0008] On one hand, the radiating patch is circular and formed on the upper surface of the dielectric substrate through a metallization process. Its material is preferably copper, and its diameter is l. inA Y-shaped groove is etched at the center of the circular radiating patch, which physically divides the patch surface into three equal-area fan-shaped isolation regions. By forming a physical division at the center of the radiating patch, the Y-shaped groove divides the patch surface into three mutually isolated independent regions, thereby effectively blocking the coupling path between surface currents excited by different feed ports, becoming the core decoupling structure for achieving high isolation between ports.

[0009] Furthermore, the three coaxial feed ports are strictly symmetrically distributed around the center of the radiating patch, with each port at the same distance from the center (a), and the angle between adjacent ports is 120°. This symmetrical layout forms the important foundation of the entire design. Due to its complete rotational symmetry, during design optimization and simulation, only the S-parameters of one port (such as return loss and isolation from other ports) need to be analyzed in detail to fully deduce the performance of all other ports, thus greatly simplifying the design and analysis process. Simultaneously, each port is precisely positioned within an independent sub-region defined by the "Y"-shaped slot. This layout not only physically restricts the coupling paths between ports, effectively reducing mutual interference, but also ensures that each port can primarily excite and control the radiation direction corresponding to its sub-region. The beams generated by the excitation of each of the three ports cover approximately 120° of fan-shaped direction on the horizontal plane, complementing each other and jointly achieving 360° omnidirectional radiation coverage on the horizontal plane. This effective directional coverage fundamentally benefits from the physical isolation of the surface current paths of each region by the "Y"-shaped slot and the symmetrical and precise matching of the feed port positions.

[0010] Furthermore, nine first metallized vias are distributed circumferentially along the edge of the circular radiating patch, grouped into three groups of three. Each group of vias is evenly spaced along the edge centerline, with a diameter of D. h The center-to-center distance between adjacent vias S h = d h +D h , where d h This is the distance from the edge of the via to the edge of the patch. The first metallized via is used to directly electrically connect the radiating patch to the underlying ground plane, thereby stabilizing the potential, suppressing edge diffraction, and assisting in decoupling.

[0011] Simultaneously, a coplanar but electrically isolated circular outer ring is provided around the radiating patch, with an outer diameter of l. out The ring width is w r Furthermore, the ring is connected to the ground plane via three second metallized vias, which are aligned radially with the three feed ports and connected to the ground plane. This structure constitutes an additional grounding and tuning unit, which can further optimize surface current distribution, enhance port isolation, and fine-tune the antenna's resonant frequency.

[0012] The dielectric substrate is made of microwave dielectric material such as FR-4 and has a complete planar structure with a relative permittivity of ε. r The diameter of the substrate is l. s The overall size is larger than the upper radiating patch and outer ring structure. Furthermore, a ground layer, preferably made of copper, is covered on the lower surface of the dielectric substrate. A circular matching groove, with a diameter of D, is etched on the ground layer corresponding to the projected position of each feed port. p Furthermore, the center of the circle coincides with the projection center of the corresponding port. This circular matching slot structure is mainly used to adjust the input impedance of the feed point, realize impedance transformation with the coaxial feed line, and ultimately match the input impedance of each port to the standard 50 Ω.

[0013] In summary, this invention provides a compact, common-aperture multi-feed patch antenna structure based on a single-layer dielectric substrate. This structure, through the integrated design of components such as a central "Y"-shaped slot, an edge metal via array, an outer grounding ring, and a grounding layer matching slot, effectively suppresses mutual coupling between multiple ports while promoting the complementarity of the radiation patterns of each port in the horizontal plane. This hardware solution provides a practical structural prototype for antenna systems requiring high port isolation and wide-angle coverage within a limited space.

[0014] Compared with the prior art, the common aperture multi-fed patch antenna structure provided by the present invention has the following significant advantages:

[0015] By physically dividing the radiating patch through the central "Y"-shaped slot, the surface current coupling path between different feed ports is fundamentally cut off. Combined with the edge metallized vias and the outer ring grounding structure, the isolation between each feed port is increased to more than 14 dB, effectively solving the problem of strong mutual coupling when integrating multiple ports.

[0016] By utilizing the symmetrical 120° layout of the three feed ports and the directional isolation effect of the "Y"-shaped slot, each port excites a fan-shaped beam of approximately 120°. The three beams naturally complement each other on the horizontal plane, achieving effective omnidirectional radiation coverage of nearly 360°, thus overcoming the narrow beam defect of traditional single-feed patch antennas.

[0017] The aforementioned high-performance specifications are achieved within a compact aperture of a single circular radiating patch and a single-layer dielectric substrate. Through the coordinated design of a "Y"-shaped slot, symmetrical feeding, edge vias, patch outer ring, and ground plane matching slot, the antenna size is minimized while maintaining good impedance matching and radiation efficiency.

[0018] The entire structure exhibits complete rotational symmetry, greatly simplifying the design, simulation, and optimization process. This principle can be extended to systems with more ports (such as N-ports), providing a flexible and reliable hardware foundation for applications requiring multi-sector coverage, such as indoor positioning and integrated sensing. Attached Figure Description

[0019] Figure 1 This is a three-dimensional exploded view of the structure of the present invention. 1 is a radiating patch, 2 is a dielectric substrate, and 3 is a grounding layer.

[0020] Figure 2 This is a top view of the antenna structure. 11 is a circular radiating patch, 12 is a "Y"-shaped slot, 13 is the outer ring of the circular patch, 21 is the feed port, 22 is the first metallized via, and 23 is the second metallized via.

[0021] Figure 3 This is a bottom view of the antenna structure. 31 is a circular slot.

[0022] Figure 4 The figure shows the S-parameter simulation results of the common aperture patch antenna in the CST simulation software.

[0023] Figure 5 This is the 3D radiation pattern of the common aperture patch antenna in CST simulation software.

[0024] Figure 6 The diagrams are 1D (θ = 0°) radiation patterns, where (a) is the 1D (θ = 0°) radiation pattern of the common aperture patch antenna excited at feed port 1 in the CST simulation software; (b) is the 1D (θ = 0°) radiation pattern of the common aperture patch antenna excited at feed port 2 in the CST simulation software; and (c) is the 1D (θ = 0°) radiation pattern of the common aperture patch antenna excited at feed port 3 in the CST simulation software. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] This invention provides a three-port common aperture patch antenna operating in the 5.83 GHz to 5.9 GHz frequency band to specifically illustrate the embodiments of this invention.

[0027] like Figure 1 As shown, the common aperture multi-feed patch antenna structure provided by the present invention includes, from top to bottom, a radiating patch 1, a dielectric substrate 2, and a grounding layer 3.

[0028] like Figure 2As shown, the radiating patch 1 is circular (marked as 11) and is formed on the upper surface of the dielectric substrate 2 through a metallization process. The preferred material is copper, and its diameter is 50 mm. A Y-shaped groove 12 is etched in the center of the circular radiating patch 11. This groove physically divides the patch surface into three fan-shaped isolation regions of equal area, effectively blocking the coupling path between surface currents excited by different feed ports. This is the core decoupling structure for achieving high isolation between ports.

[0029] Three coaxial feed ports 21 are arranged symmetrically around the center of the radiating patch 11. Each feed port has a diameter of 1.2 mm, a distance of 6 mm from the center, and an angle of 120° between adjacent ports. Each port is precisely positioned within an independent sub-region defined by the "Y"-shaped slot 12. The beams generated by the excitation of each of the three ports cover approximately 120° of a fan-shaped area on the horizontal plane, complementing each other to achieve 360° omnidirectional radiation coverage on the horizontal plane.

[0030] Multiple first metallized vias 22 are evenly distributed circumferentially along the edge of the circular radiating patch 11. The via diameter is 1.2 mm, and the spacing between adjacent first metallized vias in each group is 0.98 mm. The first metallized vias 22 directly connect the radiating patch 11 to the bottom ground layer 3, which plays a role in stabilizing the potential, suppressing edge diffraction, and assisting in decoupling.

[0031] A coplanar but electrically isolated circular outer ring 13 is provided around the radiating patch 11. The outer diameter of the ring is 68 mm and the width is 6 mm. This outer ring is connected to the ground layer 3 through three second metallized vias 23, each with a diameter of 1.2 mm. These vias are aligned radially with the three feed ports 21. This structure constitutes an additional grounding and tuning unit, which can further optimize the surface current distribution, enhance port isolation, and fine-tune the antenna's resonant frequency.

[0032] The dielectric substrate 2 is made of microwave dielectric material such as FR-4 and is a complete flat plate structure with a relative permittivity of 4.3 and a diameter of 80 mm. The overall size of the substrate is larger than the radiating patch 11 and the outer ring 13 above it, with the width of the excess portion being Δ = 6 mm. It must meet the condition 0 < Δ < λ / 4 = 12.75 mm (where λ is the antenna operating wavelength, and the operating frequency used in the experiment is 5.88 GHz) to effectively suppress edge diffraction.

[0033] like Figure 3As shown, a ground layer 3 covers the lower surface of the dielectric substrate 2. A circular matching groove 31, with a diameter of 6.2 mm, is etched on the ground layer 3 corresponding to the projected position of each feed port 21, and its center coincides with the projected center of the corresponding port. This circular matching groove structure is mainly used to adjust the input impedance of the feed point, realizing impedance transformation with the coaxial feed line, and ultimately matching the input impedance of each port to the standard 50 Ω.

[0034] In summary, through the specific structural combination and dimensional design described above, this invention achieves high isolation and omnidirectional horizontal radiation coverage for multiple feed ports within a compact, common aperture. (Appendix) Figures 4 to 6 The simulation and experimental results shown verify the good performance of the structure.

Claims

1. A common-aperture multi-fed patch antenna structure capable of omnidirectional radiation in a horizontal plane, characterized in that, The common aperture patch antenna includes a radiating patch, a dielectric substrate, a ground layer, and three feed ports. The radiating patch is a symmetrical circular patch with a "Y"-shaped groove in the center. The "Y"-shaped groove is used to isolate the surface current excited by different feed ports. On the edge of the symmetrical circular radiating patch, there are three sets of first metallized vias distributed circumferentially. Each set contains several vias and is used to electrically connect the radiating patch to the ground plane. A circular patch outer ring is constructed around the radiating patch, and the patch outer ring is connected to the ground layer through three second metallized vias; A circular matching slot is constructed on the grounding layer corresponding to the position of each feed port to achieve impedance matching of the feed port.

2. The structure according to claim 1, characterized in that, The "Y"-shaped groove structure is configured to divide the surface of the circular radiating patch into three isolation regions corresponding to the number of feed ports.

3. The structure according to claim 1, characterized in that, The three power supply ports are symmetrically distributed about the center of the circular radiating patch, and each port is located within an isolation area divided by the "Y"-shaped groove structure.

4. The structure according to claim 1, characterized in that, The first metallized vias are grouped into three groups; the central via in each group is strictly aligned with the direction pointed to by one branch of the central "Y" shaped groove.

5. The structure according to claim 4, characterized in that, The center-to-center distance between adjacent first metallized vias S h satisfy S h = d h + D h ,in D h The diameter of the via is d h This is the distance from the edge of the via to the edge of the radiating patch.

6. The structure according to claim 1, characterized in that, The second metallized via corresponds one-to-one with the three feed ports, and each group of corresponding vias and ports is collinear with the center of the radiating patch, thus forming a symmetrical grounding and radiating structure.

7. The structure according to claim 1, characterized in that, The length of the "Y"-shaped slot and the positions of the three feed ports together control the isolation between each feed port and the effective radiation surface direction and range of each feed port when it is working.

8. The structure according to claim 1, characterized in that, The circular slot is sized to match the input impedance of the feed port to 50 Ω.

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