Broadband patch antenna based on artificial surface plasmon structure

Abstract

A broadband patch antenna based on an artificial surface plasmon structure belongs to the technical field of metamaterial antennas, solves the problem of how to improve the working bandwidth of a patch antenna, receives an input electromagnetic signal by using a microstrip feeder line of a fork-shaped structure, optimizes impedance matching, couples the electromagnetic signal to a metal patch through a feed slot, and improves the working bandwidth of the patch antenna. The comb tooth structure arranged in the feed slot can be coupled with a plurality of resonant frequencies through a plurality of comb teeth, the bandwidth can be obviously widened, the artificial surface plasmon structure arranged on the metal patch comprises grooves with different depths, and the design that the depths of the grooves are gradually changed can generate multimode resonance, so that the working bandwidth of the patch antenna is expanded, the antenna performance is excellent, and the antenna has a wide application prospect. Meanwhile, the patch antenna is simple in structure and convenient to process.

Description

Technical Field

[0001] The present invention belongs to the technical field of metamaterial antennas and relates to a broadband patch antenna based on an artificial surface plasmon structure. Background Art

[0002] With the rapid development of science and technology, wireless communication technology has gradually permeated every aspect of life, and the number of wireless devices has increased year by year. Antennas, as key transmitting and receiving components in wireless communication devices, are also facing the need to meet higher performance targets, developing towards broadband, multi-functionality, and high gain. Patch antennas offer advantages such as small size, light weight, simple manufacturing, and ease of integration. They also feature wide beamwidth, wide impedance bandwidth, excellent filtering characteristics, and polarization flexibility, making them widely used in wireless communication system terminals and mobile client devices.

[0003] With the rapid development and application of mobile communications and radio frequency identification technologies, terminal devices are increasingly demanding greater channel capacity, wider bandwidth, and faster transmission rates for wireless communication systems. This has led to increasingly stringent requirements for antenna performance. Traditional patch antennas have limited bandwidth, and achieving broadband patch antennas within a limited space is a pressing issue in wireless communication systems.

[0004] Spoof Surface Plasmon Polaritons (SSPPs) are artificial materials with special optical properties. They are usually composed of subwavelength unit structures. These units are designed into specific geometric shapes and can control the phase, amplitude, propagation direction, etc. of electromagnetic waves. Their key feature is the ability to highly modulate electromagnetic waves at the surface or interface. Existing technologies, such as the invention patent with application publication number CN116864988A, disclose a short-circuited patch antenna structure. By loading an artificial surface plasmon structure with a gradient groove depth on the non-radiating edge of a metal patch, combined with the miniaturization advantage of the short-circuited patch antenna, the antenna size is significantly reduced. However, it does not effectively expand the operating bandwidth and still does not solve the broadband problem of patch antennas. Summary of the Invention

[0005] The technical problem to be solved by the present invention is how to increase the working bandwidth of the patch antenna.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] A broadband patch antenna based on an artificial surface plasmon structure includes a first dielectric substrate, a ground plane, and a second dielectric substrate arranged in parallel from top to bottom;

[0008] A microstrip feed line is provided on the lower surface of the second dielectric substrate, one end of the microstrip feed line is aligned with any bottom edge of the second dielectric substrate as an input port, and the other end of the microstrip feed line extends in a direction perpendicular to the bottom edge;

[0009] A feeding slot is provided at the center of the ground plane, and a plurality of comb-shaped teeth are provided on the long sides of the feeding slot;

[0010] A metal patch is provided on the upper surface of the first dielectric substrate, and artificial surface plasmon structures are loaded on both sides of the long sides of the metal patch.

[0011] Furthermore, the microstrip feeder includes a rectangular microstrip line and an L-shaped microstrip line, one end of the rectangular microstrip line serves as an input port, and the other end of the rectangular microstrip line is connected to the short sides of the two L-shaped microstrip lines. The two L-shaped microstrip lines are symmetrically distributed about the rectangular microstrip line, so that the microstrip feeder forms a fork structure.

[0012] Furthermore, the short side of the L-shaped microstrip line is perpendicular to the rectangular microstrip line, and the long side of the L-shaped microstrip line passes over a vertical projection of the feeding slot on the second dielectric substrate.

[0013] Furthermore, a vertical projection of a long side of the feeding slot on the second dielectric substrate is perpendicular to a long side of the L-shaped microstrip line.

[0014] Furthermore, a tooth-shaped structure is provided on the long side of the L-shaped microstrip line, specifically, a plurality of first grooves are provided along the long side of the L-shaped microstrip line, and the plurality of first grooves are of equal depth and equal spacing.

[0015] Furthermore, tooth-shaped structures are provided on both sides of the long side of the L-shaped microstrip line.

[0016] Furthermore, the plurality of comb-shaped teeth have equal depth and equal spacing.

[0017] Furthermore, vertical projections of the two metal patches on the ground plane overlap with the feeding slot, and the two metal patches are symmetrically distributed with respect to the feeding slot.

[0018] Furthermore, the artificial surface plasmon structure is specifically configured to have a plurality of second grooves formed along the long side of the metal patch. The plurality of second grooves are spaced apart, and the depth of the second grooves increases first and then decreases, forming a triangular waveform gradient.

[0019] Furthermore, the first dielectric substrate and the second dielectric substrate are both made of Rogers RT5880, with a dielectric constant of 2.2 and a loss tangent of 0.0009.

[0020] The advantages of the present invention are:

[0021] The present invention utilizes a fork-shaped microstrip feeder to receive input electromagnetic signals, optimizes impedance matching, and then couples the electromagnetic signals to a metal patch through a feed slot. The comb-tooth structure provided in the feed slot can couple multiple resonant frequencies through multiple comb teeth, significantly widening the bandwidth. The artificial surface plasmon structure provided on the metal patch contains grooves of different depths, and the design of gradually varying groove depths can generate multi-mode resonance, thereby expanding the working bandwidth of the patch antenna. The antenna has excellent performance, and the patch antenna has a simple structure and is easy to process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is an exploded view of a broadband patch antenna based on an artificial surface plasmon structure according to the first embodiment of the present invention;

[0023] Figure 2 1 is a top view of a broadband patch antenna based on an artificial surface plasmon structure according to a first embodiment of the present invention;

[0024] Figure 3 is a top view of the ground plane of the first embodiment of the present invention;

[0025] Figure 4 1 is a bottom view of a broadband patch antenna based on an artificial surface plasmon structure according to a first embodiment of the present invention;

[0026] Figure 5 Schematic diagram of a vertical projection of a feeding slot and a microstrip feeding line on a first dielectric substrate according to a first embodiment of the present invention;

[0027] Figure 6 Schematic diagram of a vertical projection of the feeding slot on the second dielectric substrate according to the first embodiment of the present invention;

[0028] Figure 7 1 is an S-parameter diagram of a broadband patch antenna based on an artificial surface plasmon structure according to the first embodiment of the present invention;

[0029] Figure 8 : This is the radiation pattern of the broadband patch antenna based on the artificial surface plasmon structure at 44 GHz according to the first embodiment of the present invention;

[0030] Reference numerals: 10, second dielectric substrate; 11, input port; 12, microstrip feed line;

[0031] 20. Ground plane; 21. Feed gap;

[0032] 30. First dielectric substrate; 31. Metal patch. DETAILED DESCRIPTION

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] The technical solution of the present invention is further described below with reference to the accompanying drawings and specific embodiments:

[0035] Example 1

[0036] like Figure 1 As shown, specifically, a broadband patch antenna based on an artificial surface plasmon structure is disclosed, comprising a first dielectric substrate, a ground plane, and a second dielectric substrate arranged in parallel from top to bottom.

[0037] A microstrip feeder is provided on the lower surface of the second dielectric substrate. One end of the microstrip feeder is aligned with any bottom edge of the second dielectric substrate as an input port, and the other end of the microstrip feeder extends in a direction perpendicular to the bottom edge.

[0038] The microstrip feed line includes a rectangular microstrip line and an L-shaped microstrip line, one end of the rectangular microstrip line serves as an input port, the other end of the rectangular microstrip line is connected to the short sides of the two L-shaped microstrip lines, the short side of the L-shaped microstrip line is perpendicular to the rectangular microstrip line, the long sides of the two L-shaped microstrip lines are parallel to and perpendicular to the bottom side aligned with the input port, and the long side of the L-shaped microstrip line crosses the vertical projection of the feeding slot on the second dielectric substrate, such as Figure 6 As shown; the two L-shaped microstrip lines are distributed on both sides of the rectangular microstrip line with the midline on the short side of the rectangular microstrip line as the symmetry axis, so that the microstrip feed line forms a fork structure.

[0039] Furthermore, a tooth-like structure is provided on the long side of the L-shaped microstrip line. The tooth-like structure is specifically a plurality of first grooves provided along the long side of the L-shaped microstrip line. The plurality of first grooves are of equal depth and equal spacing. The tooth-like structure is provided on both sides of the long side of the L-shaped microstrip line.

[0040] In this embodiment, a fork-shaped microstrip feeder provided on the lower surface of the second dielectric substrate receives an electromagnetic signal through an input port. At the same time, a toothed structure is provided on the output end of the fork-shaped microstrip feeder, which can better excite the radiation mode generated by the patch, so that the fork-shaped microstrip feeder can meet impedance matching, specifically meeting the characteristic impedance of 50 ohms. In this embodiment, the second dielectric substrate adopts Rogers RT5880 (RT / duroid5880), which is made of polytetrafluoroethylene glass fiber reinforced material. The microfibers inside the board are randomly distributed in the material, which can greatly ensure the strength requirements of the board during the circuit application process and the production process. Its dielectric constant is 2.2, and the loss tangent value is 0.0009. It has the characteristics of low loss, which is conducive to improving the radiation efficiency of the patch antenna.

[0041] Furthermore, the ground plane is provided on the upper surface of the second dielectric substrate by copper cladding, and the side of the ground plane away from the second dielectric substrate is connected to the lower surface of the first dielectric substrate by copper cladding, thereby ensuring a stable return path for the signal while shielding and isolating external signal interference. In this embodiment, no electrical path is required between the dielectric substrate and the ground plane, and the fed RF signal is transmitted only by slot coupling, without the need for electrical connection.

[0042] A feeding slot is provided at the center of the ground plane. The vertical projection of the long side of the feeding slot on the second dielectric substrate is perpendicular to the long side of the L-shaped microstrip line. Specifically, the long side of the feeding slot is 2.1 mm.

[0043] Furthermore, a plurality of comb-shaped teeth are provided on the long side of the feeding slot, the plurality of comb-shaped teeth are at equal intervals and have equal depths, and the width of the comb-shaped teeth is 0.1 mm.

[0044] In this embodiment, the comb teeth and feed slot are hollow structures defined within the ground plane, extending through both the upper and lower surfaces. This embodiment couples electromagnetic signals received by the microstrip feed line to the first dielectric substrate via the feed slot, located at the center of the ground plane. The comb teeth structure provided by the feed slot is used to excite multimode resonance. By coupling multiple resonant frequencies through multiple comb teeth, the bandwidth can be significantly broadened.

[0045] Specifically, the ground plane is rectangular and has a size of 6.2 mm*4.5 mm.

[0046] The upper surface of the first dielectric substrate is provided with metal patches, and the vertical projections of the two metal patches on the ground plane overlap with the feeding gap, such as Figure 5 As shown, the two metal patches are symmetrically distributed on the upper surface of the first dielectric substrate with the midline on the short side of the feeding slot as the symmetry axis.

[0047] Furthermore, artificial surface plasmon structures are loaded on both sides of the long side of the metal patch. Specifically, multiple second grooves are opened along the long side of the metal patch, and the multiple second grooves are arranged at intervals. The depth change trend of the second grooves is first increasing and then decreasing, showing a triangular waveform gradient.

[0048] like Figure 2 As shown, the metal patch can be a rectangular metal patch. Two metal patches are arranged side by side on the upper surface of the first dielectric substrate. An artificial surface plasmon structure (SSPPs) is formed by opening a plurality of trapezoidal grooves of different depths on the long sides of the rectangular metal patch. The depths of the plurality of second grooves first increase and then decrease along the long sides of the metal patch, so that the plurality of second grooves present a triangular shape, as shown in FIG. Figure 2 Specifically, the depth of every two second grooves is first gradually increased, and then every two second grooves are gradually reduced, and the depth of the second grooves is set in a cycle.

[0049] In this embodiment, the metal patch provided on the surface of the first dielectric substrate is used for electromagnetic energy emission. The artificial surface plasmon structure provided on the metal patch can increase the equivalent dielectric constant and reduce the resonant frequency, thereby making the antenna size smaller at the same frequency. The artificial surface plasmon structure disrupts the uniform distribution of current on the surface of the metal patch and introduces multipath current, which is equivalent to increasing the equivalent electrical length of the antenna, thereby widening the bandwidth, optimizing the radiation pattern, reducing the sidelobe level, and improving the mainlobe gain.

[0050] Because a single metal patch loaded with an artificial surface plasmon structure inherently introduces additional resonant paths, this embodiment employs two metal patches arranged side by side on the top surface. This creates a gap between adjacent patches loaded with artificial surface plasmon structures. This gap generates strong electromagnetic coupling, introducing new resonant modes whose resonant frequencies interact with the single-patch modes, forming coupled resonant pairs. These coupled modes have closely spaced frequencies, appearing as a continuous, wide bandwidth on the impedance curve. Fringe field coupling at the gap allows current to be shared between the two patches, further dispersing the current density and reducing energy concentration at a single resonant point.

[0051] This embodiment can also achieve impedance matching overlap of multiple resonance points by optimizing the gap width, thereby further improving the bandwidth.

[0052] In this embodiment, the first dielectric substrate also adopts Rogers RT5880, with a dielectric constant of 2.2 and a loss tangent of 0.0009.

[0053] Working principle:

[0054] The radio frequency electromagnetic signal enters the second dielectric substrate from the input port, and the impedance matching is optimized through the fork structure set on the feed line to ensure the quality of the electromagnetic signal. The electromagnetic signal received by the microstrip feed line is coupled to the first dielectric substrate through the feeding slot, and the comb-tooth structure set in the feeding slot is used to excite multi-mode resonance. By coupling multiple resonant frequencies through multiple comb teeth, the bandwidth can be significantly widened. Finally, the coupled signal is converted into artificial surface plasmons (surface waves) through the artificial surface plasmon structure loaded on the metal patch. The design of the gradient groove depth expands the operating bandwidth of the patch antenna, converting the surface waves into radiated waves, which are radiated from the top of the patch antenna.

[0055] like Figure 4 As shown, based on the broadband patch antenna based on the artificial surface plasmon structure provided by the present invention, the S11 parameter satisfies S11<-10dB in the frequency band of 29.26~62.67GHz, as shown in FIG. Figure 5 As shown in the figure, at 44 GHz, the patch antenna exhibits stable directional radiation, indicating that the electromagnetic signals input from the input port can be well transmitted through the antenna, with good impedance matching, high transmission efficiency, minimal reflection, and effective suppression of surface wave loss.

[0056] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A broadband patch antenna based on an artificial surface plasmon structure, characterized in that: It includes a first dielectric substrate, a ground plane, and a second dielectric substrate arranged in parallel from top to bottom; A microstrip feed line is provided on the lower surface of the second dielectric substrate, one end of the microstrip feed line is aligned with any bottom edge of the second dielectric substrate as an input port, and the other end of the microstrip feed line extends in a direction perpendicular to the bottom edge; A feeding slot is provided at the center of the ground plane, and a plurality of comb-shaped teeth are provided on the long sides of the feeding slot; A metal patch is provided on the upper surface of the first dielectric substrate, and artificial surface plasmon structures are loaded on both sides of the long sides of the metal patch.

2. The broadband patch antenna based on artificial surface plasmon structure according to claim 1, characterized in that: The microstrip feeder includes a rectangular microstrip line and an L-shaped microstrip line. One end of the rectangular microstrip line serves as an input port, and the other end of the rectangular microstrip line is connected to the short sides of two L-shaped microstrip lines. The two L-shaped microstrip lines are symmetrically distributed about the rectangular microstrip line, so that the microstrip feeder forms a fork structure.

3. The broadband patch antenna based on artificial surface plasmon structure according to claim 2, characterized in that: The short side of the L-shaped microstrip line is perpendicular to the rectangular microstrip line, and the long side of the L-shaped microstrip line passes over the vertical projection of the feeding slot on the second dielectric substrate.

4. The broadband patch antenna based on artificial surface plasmon structure according to claim 2, characterized in that: A vertical projection of the long side of the feeding slot on the second dielectric substrate is perpendicular to the long side of the L-shaped microstrip line.

5. The broadband patch antenna based on artificial surface plasmon structure according to claim 2, characterized in that: A tooth-shaped structure is provided on the long side of the L-shaped microstrip line. Specifically, a plurality of first grooves are provided along the long side of the L-shaped microstrip line. The plurality of first grooves have equal depths and equal spacings.

6. The broadband patch antenna based on artificial surface plasmon structure according to claim 5, characterized in that: Both sides of the long side of the L-shaped microstrip line are provided with tooth structures.

7. The broadband patch antenna based on artificial surface plasmon structure according to claim 1, characterized in that: The plurality of comb-shaped teeth have equal depths and equal spacings.

8. The broadband patch antenna based on artificial surface plasmon structure according to claim 1, characterized in that: The vertical projections of the two metal patches on the ground plane overlap with the feeding slot, and the two metal patches are symmetrically distributed with respect to the feeding slot.

9. The broadband patch antenna based on artificial surface plasmon structure according to claim 1, characterized in that: The artificial surface plasmon structure is specifically configured by providing a plurality of second grooves along the long side of the metal patch. The plurality of second grooves are arranged at intervals, and the depth variation trend of the second grooves is first increasing and then decreasing, showing a triangular waveform gradient.

10. The broadband patch antenna based on artificial surface plasmon structure according to claim 1, characterized in that: The first dielectric substrate and the second dielectric substrate are both made of Rogers RT5880, with a dielectric constant of 2.2 and a loss tangent of 0.0009.

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