A pencil beam slot array antenna based on valley photonic crystal waveguide

Abstract

The application discloses a pencil beam slot array antenna based on valley photonic crystal waveguide, wherein a signal connector is used to connect a signal transceiving system and the valley photonic crystal waveguide; the valley photonic crystal waveguide is composed of valley photonic crystals arranged in a triangular lattice, a valley photonic crystal cell structure is composed of metal triangular columns placed in a dielectric material, and the upper and lower ends of the metal triangular columns are connected with parallel metal plates; and a radiation structure is a slot array opened in the upper end metal plate of the second valley photonic crystal waveguide, and the center of a single slot structure is located at the center position of the upper and lower adjacent valley photonic crystal cell centers. The application can radiate a pencil type beam under single port feeding, realizes two-dimensional beam shaping, has a simple and compact structure, and can still work stably in a working frequency range when the valley photonic crystal waveguide structure part is damaged, has strong reliability and anti-interference ability, and can be applied to wireless communication scenes with high requirements on the low profile, stability and anti-interference ability of the antenna.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communication antennas, and in particular relates to a pencil beam slot array antenna based on a valley photonic crystal waveguide. Background Art

[0002] Antennas, as key components for transmitting and receiving electromagnetic waves, are crucial windows for wireless communication systems to exchange information with the outside world. Among the various antennas, waveguide slot array antennas, with their low profile, compact structure, high radiation efficiency, high power capacity, and ease of integration, have garnered significant attention in the wireless communication field and have been widely used in the microwave and millimeter wave bands.

[0003] In practical applications of waveguide slot array antennas, a single linear array antenna cannot achieve the high gain and pencil beam pattern requirements. To meet these requirements, multiple linear array antennas are typically combined into a planar array. Feeding this planar array antenna requires designing a complex feed network and adding components such as power splitters. This undoubtedly increases the antenna's complexity and size, reducing its efficiency and anti-interference capabilities. Summary of the Invention

[0004] The present invention overcomes the shortcomings of the existing technology and provides a pencil beam slot array antenna based on a valley photonic crystal waveguide. The pencil beam slot array antenna can radiate a pencil beam under single-port feeding, realize two-dimensional beam shaping, and has a simple and compact structure. Even when the valley photonic crystal waveguide structure is partially damaged, the pencil beam slot array antenna can still operate stably within the operating frequency range, and has strong reliability and anti-interference ability.

[0005] The technical solution is as follows:

[0006] A pencil beam slot array antenna based on a valley photonic crystal waveguide, characterized by comprising a signal connector, a valley photonic crystal waveguide and a radiation structure;

[0007] The signal connector includes two rectangular waveguides with different short side lengths and a tapered waveguide, the waveguides are filled with dielectric material, one end of the signal connector is connected to the electromagnetic signal transceiver system, and the other end is connected to the valley photonic crystal waveguide;

[0008] The valley photonic crystal waveguide includes a first valley photonic crystal waveguide (WG1) and a second valley photonic crystal waveguide (WG2), wherein the first valley photonic crystal waveguide includes a first valley photonic crystal region (VPC1) and a third valley photonic crystal region (VPC3) arranged in a triangular lattice; the second valley photonic crystal waveguide includes a first valley photonic crystal region, a second valley photonic crystal region (VPC2), and a third valley photonic crystal region arranged in a triangular lattice, wherein each valley photonic crystal unit cell structure is composed of a metal triangular prism placed in a dielectric material, and the upper and lower ends of the metal triangular prisms are connected to parallel metal plates, and the tips of the metal triangular prisms in the first valley photonic crystal, the second valley photonic crystal, and the third valley photonic crystal are oriented in different directions;

[0009] The radiation structure is a slot array opened on the metal plate at the upper end of the second valley photonic crystal waveguide, and the center of the slot structure is located at the center position of the upper and lower adjacent valley photonic crystal cells.

[0010] Furthermore, in the signal connector, the first metal rectangular waveguide, the metal tapered waveguide, and the second metal rectangular waveguide are connected in sequence, the first metal rectangular waveguide is connected to the electromagnetic signal transceiver system, and the second metal rectangular waveguide is connected to the valley photonic crystal waveguide.

[0011] Furthermore, the dielectric material is polytetrafluoroethylene with a dielectric constant of ε=2.2.

[0012] Furthermore, the angle between the transmission direction of the signal connector and the horizontal +x-axis direction is β=14°.

[0013] Furthermore, the tips of the metal triangular prisms in the first valley photonic crystal, the second valley photonic crystal and the third valley photonic crystal are oriented in the vertical -y axis direction, the horizontal +x axis direction and the vertical +y axis direction respectively.

[0014] Furthermore, the lattice constant of the triangular lattice is p=7.92 mm, the side length of the metal triangular prism is d=3.75 mm, and the height is h=6 mm.

[0015] Furthermore, the inner cross-section short side length of the rectangular waveguide connected to the electromagnetic signal transceiver system is a=4 mm, and the inner cross-section long side length is h=6 mm; the inner cross-section short side length of the rectangular waveguide connected to the valley photonic crystal waveguide is b=5.7 mm, and the inner cross-section long side length is h=6 mm.

[0016] Furthermore, the arrangement period of the slot array in the x-axis direction is p=7.92 mm, and the arrangement period in the y-axis direction is √3*p=13.72 mm.

[0017] Furthermore, the length of the long side of the slit is l=8.3 mm, the length of the short side of the slit is w=0.65 mm, and the angle between the long side of the slit and the horizontal +x axis direction is θ=60°.

[0018] The technical solutions provided by the embodiments of the present application may have the following beneficial effects:

[0019] As can be seen from the above embodiments, the present application provides a pencil beam slot array antenna of a valley photonic crystal waveguide, which utilizes the intrinsic field of the second valley photonic crystal waveguide to present a periodic distribution in the x and y directions in the third valley photonic crystal region, and opens a two-dimensional array of slots on the metal plate at the upper end of the second valley photonic crystal waveguide to achieve a pencil-shaped radiation beam. The remaining electromagnetic signal after radiation is absorbed by the matching load connected to the first valley photonic crystal waveguide and the signal connector. Compared with the traditional slot array antenna based on rectangular waveguide and substrate integrated waveguide, it can realize the radiation of pencil-shaped beams under single-port feeding and realize two-dimensional beam shaping, which is simpler and more compact, avoiding the design of complex feeding networks and the introduction of additional devices such as power dividers. Moreover, when the valley photonic crystal waveguide structure is partially damaged, the pencil beam slot array antenna can still operate stably within the operating frequency range, and has strong reliability and anti-interference capabilities.

[0020] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0022] Figure 1 The figure is a schematic structural diagram of a pencil beam slot array antenna based on a valley photonic crystal waveguide according to an exemplary embodiment.

[0023] Figure 2 FIG. 4 is a diagram showing an energy band structure of a second valley photonic crystal waveguide according to an exemplary embodiment.

[0024] Figure 3 FIG. 4 is a graph showing antenna return loss and actual gain curves according to an exemplary embodiment.

[0025] Figure 4 1 is an E-plane and H-plane radiation pattern of an antenna at some frequency points according to an exemplary embodiment.

[0026] The reference numerals in the figure are: signal connector 1 , valley photonic crystal waveguide 2 , and radiation structure 3 . DETAILED DESCRIPTION

[0027] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The description of the exemplary embodiments is intended to apply to all alternative modifications and equivalents of the methods and materials as set forth herein. It is to be understood that other embodiments can be utilized, and structural or operational modifications can be made without departing from the scope of the present application.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0029] It is to be understood that the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. It is to be further understood that the terms "comprise", "comprising", "comprises", "including", "includes" or "contain" or "containing" when used in this specification, specify the presence of stated features, integers, steps, operations, elements, or components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. It is to be understood that the terms "if' and "as if' as used herein can be interpreted either as "when" or "once" or "in response to determining" depending on the context.

[0030] A valley plasmonic crystal waveguide based pencil beam slot array antenna according to an embodiment of the present application will be described in detail below with reference to the accompanying drawings. First, referring to Figure 1 The structure comprises a signal connector 1, a valley plasmonic crystal waveguide 2, and a radiation structure 3. The signal connector comprises two rectangular waveguides with different inner cross-sectional short side lengths and a tapered waveguide, the waveguides are filled with dielectric material, one end of the signal connector is connected to an electromagnetic signal transceiver system, and the other end is connected to the valley plasmonic crystal waveguide. The valley plasmonic crystal waveguide comprises a first valley plasmonic crystal waveguide (WG1) and a second valley plasmonic crystal waveguide (WG2). The first valley plasmonic crystal waveguide comprises a first valley plasmonic crystal (VPC1) region and a third valley plasmonic crystal (VPC3) region arranged in a triangular lattice. The second valley plasmonic crystal waveguide comprises a first valley plasmonic crystal region, a second valley plasmonic crystal (VPC2) region, and a third valley plasmonic crystal region arranged in a triangular lattice. Each valley plasmonic crystal unit cell structure is composed of a metal triangular prism placed in a dielectric material, and the upper and lower ends of the metal triangular prism are connected to parallel metal plates. The metal triangular prisms in the first, second, and third valley plasmonic crystals have different pointed ends. The radiation structure is a slot array formed in the upper metal plate of the second valley plasmonic crystal waveguide, and the center of the slot structure is located at the center of the adjacent valley plasmonic crystal unit cell.

[0031] In the pencil beam slot array antenna based on valley photonic crystal waveguide for wireless communication provided by the present invention, the slot array is arranged in two dimensions, so that the entire slot array antenna radiates a pencil beam, realizing two-dimensional beam shaping; within its operating frequency band, the valley photonic crystal waveguide mode distribution is protected by symmetry, and even when the waveguide structure is partially damaged, the mode distribution remains unchanged, so that the antenna can maintain stable operating performance within the operating frequency band; the signal connector connects to the rectangular waveguide of the signal transceiver system, and uses the first valley photonic crystal waveguide as a transition to realize low-reflection mode conversion between the rectangular waveguide mode and the second valley photonic crystal waveguide mode, so that the reflection and loss of the antenna transceiver signal within the entire operating frequency band are maintained at low indicators, so that the gain of the slot array antenna is stable and unchanged in harsh working environments, and the operating performance is not reduced.

[0032] The structure and connection method of each component will be described in detail below.

[0033] In the present invention, the signal connector 1 is composed of a first metal rectangular waveguide, a metal tapered waveguide and a second metal rectangular waveguide connected in sequence. The interior of the waveguide is filled with the same dielectric material as in the valley photonic crystal structure. The first metal rectangular waveguide is connected to the electromagnetic signal transceiver system, and the second metal rectangular waveguide is connected to the valley photonic crystal waveguide 2. The signal connector is used to connect the signal transceiver system with the valley photonic crystal waveguide. The electromagnetic signal passes through the signal connector to achieve efficient (low reflection) mode conversion between the valley photonic crystal waveguide and the signal transceiver system. This efficient mode conversion can ensure the high gain of the entire antenna. Specifically, in this embodiment, the transmission direction of the signal connector is at an angle β=14° with the x-axis direction. The short side length of the first metal rectangular waveguide is a=4mm, and the long side length is h=6mm. The short side length of the second metal rectangular waveguide is b=5.7mm, and the long side length is h=6mm. It should be noted that the short side and long side of the metal rectangular waveguide refer to the long side and short side of the cross section. The long and short side lengths of the first metal rectangular waveguide should be selected to ensure single-mode transmission of the signal connector within the antenna operating frequency band. Changing the angle β and the long and short side lengths of the second metal rectangular waveguide will affect the coupling efficiency between the valley photonic crystal waveguide and the signal transceiver system. They should be set according to actual needs.

[0034] In the present invention, the valley photonic crystal waveguide 2 is composed of valley photonic crystals arranged in a triangular lattice, wherein the first valley photonic crystal region (VPC1) and the third valley photonic crystal region (VPC3) constitute the first valley photonic crystal waveguide (WG1), and the first valley photonic crystal region, the second valley photonic crystal region (VPC2), and the third valley photonic crystal region constitute the second valley photonic crystal waveguide (WG2). The VPC1, VPC2, and VPC3 regions are directly connected along the y-axis to form WG1 and WG2. The unit cell structure of the valley photonic crystal is composed of metal triangular prisms placed in a dielectric material, and the upper and lower ends of the metal triangular prisms are connected to parallel metal plates. Specifically, in this embodiment, the lattice constant of the triangular lattice is p = 7.92 mm, the side length of the metal triangular prism is d = 3.75 mm, and the height is h = 6 mm. In a specific implementation, the tips of the metal triangular prisms in the first valley photonic crystal, the second valley photonic crystal, and the third valley photonic crystal are oriented in different directions. Preferably, the tips of the metal triangular prisms in the first valley photonic crystal, the second valley photonic crystal, and the third valley photonic crystal are oriented in the vertical -y axis direction, the horizontal +x axis direction, and the vertical +y axis direction, respectively. At this time, the working bandwidth of the valley photonic crystal waveguide is the largest, thereby making the working bandwidth of the entire antenna reach the maximum value. In the example provided by the present invention, the dielectric material selected is polytetrafluoroethylene, and the dielectric constant of the material is ε=2.2. Replacing dielectric materials with different dielectric constants can change the operating frequency band of the antenna, and the operating frequency of the antenna is inversely proportional to the square root of the dielectric constant of the dielectric material. Changing the lattice constant of the triangular lattice, the side length of the metal triangular prism, and the height of the metal triangular prism can also change the operating frequency band of the antenna. At the same time, the relative relationship between the height of the metal triangular prism and the length of the long side of the above-mentioned second metal rectangular waveguide will affect the coupling efficiency between the valley photonic crystal waveguide and the signal transceiver system, and is set according to actual needs.

[0035] In the present invention, the radiation structure 3 is a slot array provided on the metal plate at the upper end of the second valley photonic crystal waveguide, and the center of the slot structure is located at the center of the adjacent valley photonic crystal cell in the y direction. Specifically, in this embodiment, the arrangement period of the slot array in the x-axis direction is p = 7.92 mm, and the arrangement period in the y-axis direction is √3*p = 13.72 mm. The radiation unit has a slot long side length of l = 8.3 mm, a slot short side length of w = 0.65 mm, and an angle between the slot long side and the horizontal +x-axis direction of θ = 60°. Changing the arrangement period of the slot array can change the beam pointing of the antenna, changing the length of the long side and short side of the slot and the number of slots can change the radiation efficiency of the antenna, and changing the angle θ can change the polarization direction of the antenna, which is set according to actual needs. It should be noted that the arrangement period in the x and y directions cannot exceed the wavelength, otherwise the radiation beam will have strong side lobes.

[0036] The working principle of the pencil beam slot array antenna based on valley photonic crystal waveguide is as follows:

[0037] The eigenfield of the second-valley photonic crystal waveguide exhibits a periodic distribution in the x and y directions within the third-valley photonic crystal region. The present invention utilizes this property to create a two-dimensional array of slots on the surface of the second-valley photonic crystal waveguide. Because the eigenmodes of the second-valley photonic crystal waveguide have very little overlap with the field patterns of conventional electromagnetic waveguide devices, such as rectangular waveguides, directly connecting conventional electromagnetic waveguide devices to the second-valley photonic crystal waveguide results in significant signal reflection during transmission, severely impacting antenna gain. To address the reflection problem caused by mode mismatch, the present invention utilizes a first-valley photonic crystal waveguide that can be connected to the second-valley photonic crystal waveguide without reflection as a mode transition structure (directly connecting WG1 and WG2 along the x-direction. Since the wave vectors of the two waveguides are matched, a reflection-free connection between WG1 and WG2 is achieved, i.e., mode transition is achieved). This is then connected to the first-valley photonic crystal waveguide via a specially designed signal connector, achieving reflection-free mode conversion between the signal transceiver system and the second-valley photonic crystal waveguide. In order to achieve mode matching between the traditional electromagnetic waveguide device and the first valley photonic crystal waveguide, the present invention adopts a specially designed rectangular waveguide when designing the signal connector. The specially designed rectangular waveguide has multiple eigenmodes in the antenna's operating frequency range. To avoid the existence of multi-mode signals during signal excitation, the present invention connects a single-mode rectangular waveguide to the left end of the specially designed rectangular waveguide and uses a tapered waveguide for mode field matching to avoid reflection problems caused by mode mismatch between rectangular waveguides. When the electromagnetic signal enters the second valley photonic crystal waveguide, refer to Figure 2 Within the single-mode operating frequency range of the second-valley photonic crystal waveguide (i.e., 21.8GHz-22.35GHz), a pencil-shaped radiation beam can be achieved by creating a two-dimensional slot array that cuts the surface current of the second-valley photonic crystal waveguide. The remaining electromagnetic signal after radiation is absorbed by the first-valley photonic crystal waveguide and the signal connector connected to the matching load.

[0038] Reference Figure 3 , which shows the gain and return loss of the constructed pencil beam slot array antenna based on valley photonic crystal waveguide in the entire working frequency band. It can be seen that the antenna has a very low return loss of less than -20dB in the frequency range of 21.8GHz-22.35GHz, and the antenna gain is very high, all above 21.5dBi, and the peak antenna gain can reach 23.3dBi.

[0039] Reference Figure 4Figure 3 shows the far-field gain patterns of the constructed pencil beam slot array antenna based on the valley photonic crystal waveguide in the E-plane and H-plane at 21.9 GHz and 22.3 GHz, respectively. It can be seen that the antenna has strong directivity in both the E-plane and H-plane, and the main beam direction in the E-plane has a frequency scanning characteristic.

[0040] The pencil beam slot array antenna based on the valley photonic crystal waveguide designed in the present invention can radiate a pencil beam in the frequency range of 21.8GHz-22.35GHz by feeding only through a single port, realizing two-dimensional beamforming. Moreover, even if the valley photonic crystal waveguide structure is partially damaged, the pencil beam slot array antenna can still operate stably within the operating frequency range, and has strong reliability and anti-interference capabilities.

[0041] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the contents disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of this application and include common knowledge or customary techniques in the art that are not disclosed in this application.

[0042] It will be understood that the present application is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A pencil beam slot array antenna based on valley photonic crystal waveguide, characterized in that: including signal connectors, valley photonic crystal waveguides and radiating structures; The signal connector includes two rectangular waveguides with different short side lengths and a tapered waveguide. The rectangular waveguide with the shorter short side, the tapered waveguide, and the rectangular waveguide with the longer short side are connected in sequence. The waveguides are filled with dielectric material. The rectangular waveguide with the shorter short side is connected to the electromagnetic signal transceiver system, and the rectangular waveguide with the longer short side is connected to the valley photonic crystal waveguide. The valley photonic crystal waveguide includes a first valley photonic crystal waveguide (WG1) and a second valley photonic crystal waveguide (WG2). The first valley photonic crystal (VPC1) region and the third valley photonic crystal (VPC3) region constitute the first valley photonic crystal waveguide (WG1); the first valley photonic crystal region, the second valley photonic crystal (VPC2) region and the third valley photonic crystal region constitute the second valley photonic crystal waveguide (WG2). The first valley photonic crystal region, the second valley photonic crystal region and the third valley photonic crystal region are all arranged along the xy plane according to a triangular lattice. The photonic crystal unit cell structure is composed of metal triangular prisms placed in a dielectric material, and the upper and lower ends of the metal triangular prisms are connected to parallel metal plates. The tips of the metal triangular prisms in the first valley photonic crystal, the second valley photonic crystal, and the third valley photonic crystal are oriented in different directions. The extension direction of the metal triangular prisms intersects the xy plane. The intrinsic field of the second valley photonic crystal waveguide presents a periodic distribution in the x and y directions within the second valley photonic crystal region. The signal connector uses the first valley photonic crystal waveguide as a transition to achieve low-reflection mode conversion between the rectangular waveguide mode and the second valley photonic crystal waveguide mode. The radiation structure is a slot array opened on the metal plate at the upper end of the second valley photonic crystal waveguide, and the center of the slot structure is located at the center of the adjacent valley photonic crystal cell in the y direction.

2. The pencil beam slot array antenna based on valley photonic crystal waveguide according to claim 1, characterized in that: In the signal connector, the first metal rectangular waveguide, the metal tapered waveguide, and the second metal rectangular waveguide are connected in sequence. The first metal rectangular waveguide is connected to the electromagnetic signal transceiver system, and the second metal rectangular waveguide is connected to the valley photonic crystal waveguide.

3. The pencil beam slot array antenna based on valley photonic crystal waveguide according to claim 1, characterized in that: The dielectric material is polytetrafluoroethylene with a dielectric constant of ε=2.

2.

4. The pencil beam slot array antenna based on valley photonic crystal waveguide according to claim 1, characterized in that: The angle between the transmission direction of the signal connector and the horizontal +x-axis direction is β=14°.

5. The pencil beam slot array antenna based on valley photonic crystal waveguide according to claim 1, characterized in that: The tips of the metal triangular prisms in the first valley photonic crystal, the second valley photonic crystal and the third valley photonic crystal are oriented in the vertical -y axis direction, the horizontal +x axis direction and the vertical +y axis direction respectively.

6. The pencil beam slot array antenna based on valley photonic crystal waveguide according to claim 1, characterized in that: The lattice constant of the triangular lattice is p=7.92 mm, the side length of the metal triangular prism is d=3.75 mm, and the height is h=6 mm.

7. The pencil beam slot array antenna based on valley photonic crystal waveguide according to claim 1, characterized in that: The inner cross-section short side length of the rectangular waveguide connected to the electromagnetic signal transceiver system is a=4 mm, and the inner cross-section long side length is h=6 mm. The inner cross-section short side length of the rectangular waveguide connected to the valley photonic crystal waveguide is b=5.7 mm, and the inner cross-section long side length is h=6 mm.

8. The pencil beam slot array antenna based on valley photonic crystal waveguide according to claim 1, characterized in that: The arrangement period of the slot array in the x-axis direction is p=7.92 mm, and the arrangement period in the y-axis direction is *p=13.72mm.

9. The pencil beam slot array antenna based on valley photonic crystal waveguide according to claim 1, characterized in that: The length of the long side of the gap is l =8.3 mm, the length of the short side of the gap is w=0.65 mm, and the angle between the long side of the gap and the horizontal +x axis is θ=60°.

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