An asymmetric high-gain end-fire antenna based on artificial surface plasmons

Abstract

The present invention relates to the field of microwave technology, and particularly relates to an asymmetric high-gain end-fire antenna based on artificial surface plasmons, which comprises a bottom dielectric substrate and a top dielectric substrate; a trapezoidal metal layer is arranged along the end on the bottom dielectric substrate; a microstrip line is arranged on the top dielectric substrate, the trapezoidal metal layer is arranged at the grounding end of the microstrip line, and the microstrip line comprises a transition section and an artificial surface plasmon radiation strip arranged in sequence close to the trapezoidal metal layer. The trapezoidal metal layer, the transition section and the artificial surface plasmon radiation strip form a feeding network; the artificial surface plasmon radiation strip comprises a trapezoidal gradient slot and a rectangular gradient slot arranged in sequence along the transition section, the trapezoidal gradient slot and the rectangular gradient slot are coupled, and the artificial surface plasmon radiation strip has an asymmetric structure; enabling electromagnetic waves to propagate near the artificial surface plasmon structure, realizing radiation at the end through the microstrip line, having high gain and good radiation directivity, and low waveguide loss.

Description

Technical Field

[0001] The present invention relates to the field of microwave technology, and particularly to an asymmetric high-gain end-fire antenna based on artificial surface plasmons. Background Art

[0002] As a new type of electromagnetic surface wave mode, artificial surface plasmons have received extensive attention in the fields of microwave and terahertz in recent years. By regulating the electromagnetic field distribution through periodic sub-wavelength structures, they have strong field localization, low loss, and flexible dispersion characteristics, providing new ideas for the design of high-performance antennas. However, traditional SSPPs (Spoof Surface Plasmon Polaritons, i.e., artificial surface plasmons) antennas mostly adopt symmetric structure designs. The surface wave mode is restricted by symmetric boundary conditions, resulting in the broadening of the main lobe of the radiation pattern and insufficient gain, making it difficult to meet the requirements of modern communication systems for highly directional radiation. End-fire antennas are widely used in directional communication and radar systems due to their high gain and narrow beam characteristics. However, the combined research on existing SSPPs antennas and end-fire radiation modes is not sufficient, and there are generally problems such as low end-fire efficiency and beam tilt. Moreover, traditional end-fire antennas, such as Yagi-Uda antennas, rely on multi-element arrays or complex feeding structures, have the defects of large volume and low integration, and are difficult to adapt to compact radio frequency front-ends. To change this situation, it is usually attempted to combine the slow-wave characteristics of SSPPs with end-fire radiation, but their settings are mostly symmetric structures, resulting in limited gain improvement and complex feeding. Summary of the Invention

[0003] In order to solve the technical problems that existing SSPPs antennas usually adopt symmetric structures, with limited gain improvement and complex feeding, the purpose of the present invention is to provide an asymmetric high-gain end-fire antenna based on artificial surface plasmons. The specific technical solutions adopted are as follows:

[0004] The end-fire antenna includes a bottom dielectric substrate layer and a top dielectric substrate layer. A trapezoidal metal layer is arranged along the end on the bottom dielectric substrate layer. A microstrip line is arranged on the top dielectric substrate layer. The trapezoidal metal layer is arranged at the grounding end of the microstrip line, and the microstrip line includes a transition section and an artificial surface plasmon radiation strip arranged in sequence close to the trapezoidal metal layer. The trapezoidal metal layer, the transition section, and the artificial surface plasmon radiation strip form a feeding network. The artificial surface plasmon radiation strip includes a trapezoidal tapered slot and a rectangular tapered slot arranged in sequence along the transition section. The trapezoidal tapered slot and the rectangular tapered slot are coupled, and the artificial surface plasmon radiation strip has an asymmetric structure.

[0005] Preferably, the trapezoidal tapered slot and the rectangular tapered slot are respectively defined as the first periodic section and the second periodic section of the artificial surface plasmon radiation strip;

[0006] The depth of the trapezoidal tapered slot gradually increases towards the rectangular tapered slot and reaches the center of the first period segment, and then gradually decreases from the center of the first period segment to the second period segment; the depths of the rectangular tapered slots in the second period segment are all different.

[0007] Preferably, the depth range of the rectangular tapered slot is 0.5 mm to 3.5 mm.

[0008] Preferably, the length range of the artificial surface plasmon radiation strip is 48 mm to 52 mm.

[0009] Preferably, the width range of the artificial surface plasmon radiation strip is 1.1 mm to 1.7 mm, and the widths of the trapezoidal tapered slot and the rectangular tapered slot are the same.

[0010] The present invention has the following beneficial effects:

[0011] The high-gain end-fire antenna based on artificial surface plasmons proposed in this application adopts an asymmetric structure, enabling electromagnetic waves to propagate better near the artificial surface plasmon structure, and achieving effective radiation at the end through a microstrip line. That is, after the current enters, the trapezoidal metal layer at the bottom layer of the dielectric substrate transports the current upward to the microstrip line at the top layer of the dielectric substrate, so that the current can be accurately fed to the microstrip line. This not only effectively saves metal materials, but also has high gain and good radiation directivity, can maintain the integrity of energy and low waveguide loss; according to the cooperation of the first period segment and the second period segment, impedance matching can be achieved faster to improve the efficiency of the end-fire antenna. Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0013] Figure 1 It is a schematic structural diagram of the bottom layer of the dielectric substrate of an asymmetric artificial surface plasmon-based high-gain end-fire antenna provided by an embodiment of the present invention;

[0014] Figure 2 It is a schematic structural diagram of the top layer of the dielectric substrate of an asymmetric artificial surface plasmon-based high-gain end-fire antenna provided by an embodiment of the present invention;

[0015] Figure 3S-parameter diagram of an asymmetric plasmonic metasurface-based high-gain end-fire antenna provided by an embodiment of the present invention;

[0016] Figure 4 Schematic diagram of the 11G direction of an asymmetric plasmonic metasurface-based high-gain end-fire antenna provided by an embodiment of the present invention;

[0017] Figure 5 Schematic diagram of the 11.2G direction of an asymmetric plasmonic metasurface-based high-gain end-fire antenna provided by an embodiment of the present invention;

[0018] Figure 6 Schematic diagram of the 11.4G direction of an asymmetric plasmonic metasurface-based high-gain end-fire antenna provided by an embodiment of the present invention;

[0019] Figure 7 Schematic diagram of the gain and efficiency of an asymmetric plasmonic metasurface-based high-gain end-fire antenna provided by an embodiment of the present invention;

[0020] In the figure: 7, bottom layer of the dielectric substrate; 6, trapezoidal metal layer; 12, top layer of the dielectric substrate; 8, transition section; 9, plasmonic metasurface radiation strip; 10, trapezoidal tapered slot; 11, rectangular tapered slot. Detailed implementation manners

[0021] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation manners, structures, features and effects of an asymmetric plasmonic metasurface-based high-gain end-fire antenna proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0023] The following specifically describes the specific solution of an asymmetric plasmonic metasurface-based high-gain end-fire antenna provided by the present invention with reference to the accompanying drawings.

[0024] Please refer to Figure 1 and Figure 2 , which respectively show the schematic structural diagrams of the bottom layer 7 and the top layer 12 of the dielectric substrate of an asymmetric plasmonic metasurface-based high-gain end-fire antenna of the present invention.

[0025] Furthermore, an asymmetric plasmonic high-gain end-fire antenna based on artificial surface plasmons includes a bottom dielectric substrate 7 and a top dielectric substrate 12; a trapezoidal metal layer 6 is arranged along the end on the bottom dielectric substrate 7; a microstrip line is arranged on the top dielectric substrate 12, and the trapezoidal metal layer 6 is arranged at the grounding end of the microstrip line. The microstrip line includes a transition section 8 and an artificial surface plasmon radiation strip 9 arranged in sequence close to the trapezoidal metal layer 6. The trapezoidal metal layer 6, the transition section 8, and the artificial surface plasmon radiation strip 9 form a feeding network; the artificial surface plasmon radiation strip 9 includes a trapezoidal gradient slot 10 and a rectangular gradient slot 11 arranged in sequence along the transition section 8. The trapezoidal gradient slot 10 and the rectangular gradient slot 11 are coupled, and the artificial surface plasmon radiation strip 9 has an asymmetric structure.

[0026] As an alternative implementation, in this embodiment, the end-fire antenna can be fabricated using any one of the planar printed circuit board (PCB), chip process, high-temperature co-fired ceramic (HTCC), or low-temperature co-fired ceramic (LTCC) processes; among them, the planar printed circuit board process is widely used in various radio frequency and microwave devices due to its high cost-effectiveness and design flexibility; the chip process can achieve extremely high integration and performance and is suitable for occasions with strict requirements on size and weight; the high-temperature co-fired ceramic process and the low-temperature co-fired ceramic process are often used in radio frequency modules that need to withstand extreme environmental conditions due to their excellent thermal stability and mechanical strength; in practical applications, the most suitable preparation method can be selected according to specific application requirements and performance indicators.

[0027] It can be explained that the trapezoidal gradient slot 10 and the rectangular gradient slot 11 are coupled. The trapezoidal metal layer 6 on the bottom dielectric substrate 7 is used to couple and feed the trapezoidal gradient slot 10 and the rectangular gradient slot 11 in the artificial surface plasmon radiation strip 9. The impedance matching is achieved through the transition section 8 to maintain the integrity of the energy, and the waveguide loss can be reduced. That is, the feeding of the end-fire antenna is directly realized through the microstrip line combined with the trapezoidal metal layer 6 on its back, so as to simplify the feeding process and facilitate feeding, making the entire end-fire antenna more efficient, with high gain and good radiation directivity.

[0028] Please refer to Figure 3 , which shows the S-parameter diagram of an asymmetric plasmonic high-gain end-fire antenna provided by an embodiment of the present invention; it reflects that the end-fire antenna operates in the slow-wave region, and the phase constant is larger than that in the fast-wave region, making it easier to radiate an end-fire beam in the slow-wave region.

[0029] Furthermore, the trapezoidal tapered slot 10 and the rectangular tapered slot 11 are respectively defined as the first periodic segment and the second periodic segment of the artificial surface plasmon radiation strip 9;

[0030] The depth of the trapezoidal tapered slot 10 gradually increases towards the rectangular tapered slot 11 until the center of the first periodic segment, and then gradually decreases from the center of the first periodic segment to the second periodic segment; the depths of the rectangular tapered slots 11 in the second periodic segment are all different.

[0031] Specifically, in the structural layout, the part close to the transition section 8 is set as the trapezoidal tapered slot 10, that is, the first periodic segment is used to arrange the trapezoidal tapered slot 10, which is in a horn shape and cooperates with the transition section 8 to achieve impedance matching, enabling faster impedance matching and improving the efficiency of the end-fire antenna. In addition, in the second periodic segment, the trend of the rectangular tapered slot 11 forms an asymmetric structure. At this time, the phase difference on both sides of the asymmetric modulation even-mode TL (Transmission Line) is obtained, and the corresponding logical formula is:

[0032]

[0033] Among them, represents the phase difference; represents the scattering parameter; represents the coherence length.

[0034] When is an even multiple of is an odd multiple of is an odd multiple of is an even multiple of

[0035] At this time, the phase values on both sides are out of phase and end-fire cannot be achieved; conversely, when is an odd multiple of is an even multiple of

[0035] the corresponding phases are in phase, and end-fire is achieved at the end of the TL; in this embodiment, the artificial surface plasmon radiation strip 9 used in the end-fire antenna has an asymmetric structure and is in phase. While achieving end-fire, the gain can also be improved.

[0036] Furthermore, the length range of the artificial surface plasmon radiation strip 9 is 48 mm to 52 mm. This setting is used to adjust the beam width and gain of the end-fire antenna. For example, in situations where a wider beam coverage is required, by appropriately increasing the strip length, a wider signal propagation range can be achieved; conversely, if the directivity of the signal needs to be improved, reducing the strip length helps to narrow the beam width and increase the gain of the end-fire antenna.

[0037] Furthermore, the width range of the artificial surface plasmon radiation strip 9 is 1.1 mm to 1.7 mm, and the widths of the trapezoidal gradient slot 10 and the rectangular gradient slot 11 are the same; by adjusting the width of the artificial surface plasmon radiation strip 9, the beam width of the end-fire antenna can be adjusted to optimize the performance of the end-fire antenna.

[0038] Please refer to Figures 4 - 7 , which respectively show the schematic diagrams of the 11G direction, 11.2G direction, 11.4G direction, and the schematic diagrams of gain and efficiency of an asymmetric artificial surface plasmon-based high-gain end-fire antenna provided by an embodiment of the present invention; in the figure, it shows that the gain has reached 10.3 GHz, indicating that the end-fire antenna has the characteristics of high gain.

[0039] It can be understood that the artificial surface plasmon-based high-gain end-fire antenna proposed in this application adopts an asymmetric structure, enabling electromagnetic waves to propagate better near the artificial surface plasmon structure, and achieving effective radiation at the end through a microstrip line. That is, after the current enters, the trapezoidal metal layer 6 of the bottom layer 7 of the dielectric substrate transports the current upward to the microstrip line on the top layer 12 of the dielectric substrate, so that the current can be accurately fed to the microstrip line. This not only effectively saves metal materials, but also has high gain and good radiation directivity, and can maintain the integrity of energy and low waveguide loss; according to the cooperation of the first period segment and the second period segment, impedance matching can be achieved faster to improve the efficiency of the end-fire antenna.

[0040] It should be noted that: the above-mentioned sequence of embodiments of the present invention is only for description and does not represent the superiority or inferiority of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be beneficial.

[0041] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. An asymmetric plasmonic high-gain end-fire antenna based on artificial surface plasmons, characterized in that The end-fire antenna includes a bottom dielectric substrate layer and a top dielectric substrate layer; A trapezoidal metal layer is arranged along the end on the bottom dielectric substrate layer; A microstrip line is arranged on the top dielectric substrate layer. The trapezoidal metal layer is arranged at the grounding end of the microstrip line. The microstrip line includes a transition section and a plasmonic artificial surface radiation strip arranged in sequence close to the trapezoidal metal layer. The trapezoidal metal layer, the transition section and the plasmonic artificial surface radiation strip form a feeding network; The plasmonic artificial surface radiation strip includes a trapezoidal gradient slot and a rectangular gradient slot arranged in sequence along the transition section. The trapezoidal gradient slot and the rectangular gradient slot are coupled, and the plasmonic artificial surface radiation strip has an asymmetric structure; The trapezoidal gradient slot and the rectangular gradient slot are respectively defined as the first periodic section and the second periodic section of the plasmonic artificial surface radiation strip; the first periodic section is provided with the trapezoidal gradient slot, which is in a horn shape, and the depth of the trapezoidal gradient slot gradually deepens towards the rectangular gradient slot to the center of the first periodic section and gradually decreases from the center of the first periodic section to the second periodic section; the depths of the rectangular gradient slots in the second periodic section are all different, and the second periodic section constitutes an asymmetric structure.

2. The asymmetric plasmonic high-gain end-fire antenna based on artificial surface plasmons according to claim 1, wherein The depth range of the rectangular gradient slot is 0.5 mm to 3.5 mm.

3. An asymmetric plasmonic high-gain end-fire antenna based on artificial surface plasmons according to claim 1, characterized in that, The length range of the plasmonic artificial surface radiation strip is 48 mm to 52 mm.

4. An asymmetric plasmonic high-gain end-fire antenna based on artificial surface plasmons according to claim 1, characterized in that, The width range of the plasmonic artificial surface radiation strip is 1.1 mm to 1.7 mm, and the widths of the trapezoidal gradient slot and the rectangular gradient slot are the same.

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