A microwave topological photonic crystal metasurface antenna

Abstract

The present invention discloses a microwave topological photonic crystal metasurface antenna, which belongs to the field of communication technology. The present invention adopts a layered structure similar to a patch antenna, including a ground plate, a dielectric layer, a topological photonic crystal, a rectangular metal frame, and a microstrip feeder arranged from bottom to top. The topological photonic crystal is arranged above the dielectric layer, the rectangular metal frame is coated on the periphery of the topological photonic crystal, and the microstrip feeder is connected to the rectangular metal frame. The present invention can achieve multi-band characteristics and extended bandwidth. In addition, most of the electromagnetic waves propagated by the antenna within the band gap range are suppressed, and only electromagnetic waves of the angular state frequency can propagate, with smaller return loss, and the topological angular state can achieve unidirectional radiation, with better directivity at high frequencies. As a result, the antenna performance is greatly improved, which is very suitable for on-chip optical interconnection and photonic chip integration, and meets the needs of 5G / 6G communications, quantum computing, etc. for miniaturized devices.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and more particularly to a microwave topological photonic crystal metasurface antenna. Background Art

[0002] Traditional patch antennas are widely used in microwave communication systems due to their compact structure and ease of fabrication. However, their performance is limited by surface wave loss, impedance matching sensitivity, and edge scattering, resulting in reduced radiation efficiency and, in particular, insufficient stability in complex electromagnetic environments. In recent years, the introduction of topological photonic crystals has provided new insights into antenna design. Conventional microstrip antennas have a narrow bandwidth. However, by incorporating topological photonic crystals, the bandgap effect of photonic crystals can be exploited in antenna design to extend the operating frequency band and increase the antenna's bandwidth, meeting the high-bandwidth demands of modern communication systems. When electromagnetic waves are incident on photonic crystals, they inhibit their propagation within a certain frequency range. This property enables the integration of microstrip patch antennas on high-dielectric-constant substrates, effectively suppressing surface waves within the patch antenna substrate, improving the antenna's directivity and gain, and reducing backsidelobes. Regarding interference immunity, the introduction of periodic photonic crystal layers into the antenna structure allows for control of the propagation path of electromagnetic waves. The topological protection effect and the presence of specific modes within the bandgap ensure stable propagation despite structural defects or external disturbances, which is crucial for communication systems operating in harsh environments. In addition, the embedded design can make the antenna more integrated and reduce space occupation, which is particularly important for on-chip integration of modern electronic devices.

[0003] Despite the numerous advantages of microwave topological photonic crystal metasurface antennas, their design and implementation still face several challenges. First, the design of topological photonic crystals requires precise adjustments in the periodic structure and material selection to ensure the desired bandgap characteristics and topological protection effect. Second, the manufacturing technology and precision requirements of photonic crystal materials are high, which places high demands on production costs and processes. Finally, optimizing antenna performance involves comprehensive consideration of multiple aspects such as electromagnetic wave propagation, radiation pattern, and structural size, requiring in-depth simulation and optimization of the design.

[0004] Therefore, how to provide a microwave topological photonic crystal metasurface antenna that can achieve multi-band characteristics, expand bandwidth, reduce return loss, improve directivity and gain, enhance anti-interference ability and high integration is a problem that technical personnel in this field urgently need to solve. Summary of the Invention

[0005] In view of this, the present invention provides a microwave topological photonic crystal metasurface antenna, in which the electromagnetic waves propagated by the antenna will be suppressed within the band gap, the fundamental mode and high-order modes have smaller return loss, and at the same time, through the topological protection effect and specific modes within the band gap, it exhibits better directivity and gain in the high frequency band.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A microwave topological photonic crystal metasurface antenna, comprising:

[0008] A ground plate, a dielectric layer, and a topological photonic crystal are sequentially arranged from bottom to top; further comprising a rectangular metal frame and a microstrip feeder, wherein the rectangular metal frame is wrapped around the periphery of the topological photonic crystal, and the microstrip feeder is connected to the rectangular metal frame;

[0009] The topological photonic crystal is composed of periodic photonic topological insulator cells, which are divided into non-trivial domain cells and trivial domain cells; the non-trivial domain cells constitute a non-trivial domain, and the trivial domain cells constitute a trivial domain; the non-trivial domain is placed in the lower left corner of the topological photonic crystal, and the rest of the topological photonic crystal is a trivial domain;

[0010] The cross-sections of the photonic topological insulator cells are all square; there is a circular area in the center of the square cross-section of the trivial domain cell, and a rectangular strip extends from the upper, lower, left and right directions of the circular area to form a cross-shaped vein; the four corners of the square cross-section of the non-trivial domain cell are respectively provided with quarter circles, and the quarter circles on the four corners are connected by veins.

[0011] Preferably, in the trivial domain cell, the cross-shaped veins and the circular area are filled with isotropic GaAs material, and the rest is air; in the non-trivial domain cell, the four quarter circles and the connected veins are filled with isotropic GaAs material, and the rest is air.

[0012] Preferably, the GaAs material is one of triple-well resonator-phonon gallium arsenide or aluminum-containing gallium arsenide with a refractive index of 3.6.

[0013] Preferably, the non-trivial domain is composed of a 4×4 two-dimensional array of cells, and the trivial domain is located above and to the lower right of the topological photonic crystal, with the upper portion being composed of a 4×9 two-dimensional array of cells and the lower right portion being composed of a 5×4 two-dimensional array of cells.

[0014] Preferably, the ground plate is made of copper and has a size of 69 mm × 69 mm × 0.1 mm;

[0015] The dielectric layer is made of Rogers RT-duroid 5580 and has a size of 69 mm × 69 mm × 1 mm;

[0016] The rectangular metal frame is made of copper and has a size of 52 mm × 52 mm × 1.57 mm;

[0017] The microstrip feed line is made of copper and has a size of 0.95 mm×8.5 mm×1.57 mm.

[0018] Preferably, the characteristic size of the topological photonic crystal is 28.26 mm; the characteristic size of the photonic topological insulator cell is 3.14 mm;

[0019] In the mediocre domain cell, the radius of the circle is 1.11 mm, the width of the cross vein is 0.314 mm, and the length is 3.14 mm; in the non-trivial domain cell, the radius of the quarter circle is 1.11 mm, the width of the edge vein is 0.157 mm, and the length is 3.14 mm.

[0020] The above technical solution shows that the present invention provides a microwave topological photonic crystal metasurface antenna, which has the following advantages over the prior art:

[0021] (1) The finite-difference time-domain method (FDTD) was used to study the topological photonic crystal metasurface antenna. The corresponding performance parameters were obtained through simulation analysis and compared with ordinary patch antennas of the same size. It was found that the electromagnetic waves propagated by the antenna within the forbidden band, that is, the high-frequency band of 17.4-18.6 GHz, would be suppressed. Compared with ordinary patch antennas, it has smaller return loss, wider bandwidth, smaller standing wave ratio, greater radiation efficiency, better directionality of the high-order mode topological angular state frequency far-field radiation pattern, fewer stray lobes, lower side lobes and higher gain.

[0022] (2) The low-frequency fundamental mode also has smaller return loss and higher radiation efficiency than ordinary patch antennas, and the radiation pattern is basically the same, but the topological photonic crystal metasurface antenna has a higher main lobe gain and a larger front-to-back lobe suppression ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the overall structure of a microwave topological photonic crystal metasurface antenna of the present invention.

[0024] Figure 2 Schematic diagram of the unit structure and overall finite size structure of the topological photonic crystal in an embodiment of the present invention; wherein, Figure 2 (a) is a schematic diagram of a mediocre cell structure. Figure 2 (b) is a schematic diagram of the non-trivial domain cell structure. Figure 2(c) in the figure is a scatter plot of the characteristic frequencies of the topological photonic crystals formed by the two structural arrays and a topological angular mode field diagram within the band gap.

[0025] Figure 3 This is a comparison chart of the return loss versus frequency curve of an embodiment of the present invention and a common patch antenna of the same size in the high frequency band.

[0026] Figure 4 This is a comparison of the VSWR curves of the embodiment of the present invention and a common patch antenna of the same size at high frequency bands versus frequency.

[0027] Figure 5 This is a comparison chart of the radiation efficiency versus frequency curve of the embodiment of the present invention and a common patch of the same size in the high frequency band.

[0028] Figure 6 is the far-field pattern of phi=0 at the high-frequency resonant frequency of the embodiment of the present invention; wherein, Figure 6 (a) is the far-field pattern of the topological photonic crystal metasurface antenna at 17.995GHz. Figure 6 (b) is the far-field radiation pattern of a common patch antenna of the same size at 17.644 GHz.

[0029] Figure 7 This is a comparison chart of the return loss versus frequency curve of an embodiment of the present invention and a common patch antenna of the same size in the low frequency band.

[0030] Figure 8 This is a comparison of the VSWR curves of the embodiment of the present invention and a common patch antenna of the same size at low frequency bands versus frequency.

[0031] Figure 9 This is a comparison chart of the radiation efficiency versus frequency curve of the embodiment of the present invention in the low frequency band and that of a common patch of the same size.

[0032] Figure 10 is the far-field pattern of phi=0 at the low-frequency fundamental mode frequency of the embodiment of the present invention; wherein, Figure 10 (a) is the far-field pattern of the topological photonic crystal metasurface antenna fundamental mode at 3.988GHz. Figure 10 (b) is the far-field radiation pattern of the fundamental mode of an ordinary patch antenna of the same size at 1.92GHz. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] The embodiment of the present invention discloses a microwave topological photonic crystal metasurface antenna, referring to Figure 1 ,include:

[0035] From bottom to top, a ground plate 1, a dielectric layer 2, and a topological photonic crystal 5 are sequentially provided; a rectangular metal frame 4 and a microstrip feed line 3 are also provided. The rectangular metal frame 4 is wrapped around the periphery of the topological photonic crystal 5, and the microstrip feed line 3 is connected to the rectangular metal frame 4;

[0036] The topological photonic crystal 5 is composed of periodic photonic topological insulator cells, which are divided into non-trivial domain cells and trivial domain cells; the non-trivial domain cells constitute the non-trivial domain, and the trivial domain cells constitute the trivial domain; the non-trivial domain is placed in the lower left corner of the topological photonic crystal, and the rest of the topological photonic crystal is the trivial domain; specifically, the non-trivial domain is composed of a 4×4 two-dimensional array of cells, and the trivial domain is located above and below the topological photonic crystal, with the upper part composed of a 4×9 two-dimensional array of cells and the lower right part composed of a 5×4 two-dimensional array of cells.

[0037] The cross-section of the photonic topological insulator cell is square; Figure 2 As shown in (a), there is a circular area in the center of the square cross-section of the mediocre domain cell, and a rectangular strip extends from the top, bottom, left and right directions of the circular area to form a cross-shaped vein; Figure 2 As shown in (b), a quarter circle is set on each of the four corners of the square cross-section of the non-trivial domain cell, and the quarter circles on the four corners are connected by veins.

[0038] The characteristic size of the topological photonic crystal 5 is 28.26mm; the characteristic size of the photonic topological insulator cell is 3.14mm; in the mediocre domain cell, the circular radius is 1.11mm, the cross vein width is 0.314mm, and the length is 3.14mm; in the non-trivial domain cell, the quarter circle radius is 1.11mm, the edge vein width is 0.157mm, and the length is 3.14mm.

[0039] In the mediocre domain cell, the cross-shaped veins and circular regions are filled with isotropic GaAs material, with the remainder being air. In the non-trivial domain cell, the four quarter-circles and the connecting veins are filled with isotropic GaAs material, with the remainder being air. The GaAs material is either triple-well resonant-phonon GaAs or aluminum-containing GaAs with a refractive index of 3.6.

[0040] In this embodiment, the ground plate 1 is made of copper and has a size of 69 mm × 69 mm × 0.1 mm;

[0041] The material of dielectric layer 2 is Rogers RT-duroid 5580, with a size of 69 mm × 69 mm × 1 mm;

[0042] The rectangular metal frame 4 is made of copper and has a size of 52 mm × 52 mm × 1.57 mm;

[0043] The microstrip feed line 3 is made of copper and has a size of 0.95 mm×8.5 mm×1.57 mm.

[0044] In this embodiment, a gallium arsenide (GaAs) topological photonic crystal structure is embedded in a microstrip antenna, which involves the combination of precision semiconductor technology and metal processing technology:

[0045] The first step is the preparation of topological photonic crystal 5: high-quality GaAs single crystals are grown using vertical gradient freezing (VGF) or liquid-enclosed Czochralski (LEC) methods to reduce the dislocation density, and photoresist is spin-coated on the GaAs wafer. The periodic hole array, i.e., topological photonic crystal 5, is formed by exposure.

[0046] The second step is the processing of the rectangular metal frame (metal copper sheet) 4 and the microstrip feed line 3: laser cutting the copper sheet to the target size and shape, with a surface roughness of <0.1 μm,

[0047] The third step is the integration of the topological photonic crystal 5 with the rectangular metal frame 4 and the microstrip feed line 3: the etched GaAs photonic crystal is bonded to the copper sheet at 300-400°C and 10-20 MPa to form a mechanical-electrical interconnection.

[0048] The fourth step is the deposition of dielectric layer 2: Rogers RT-duroid 5580 is deposited on the surface area after bonding as the antenna dielectric layer, followed by SMA connector welding at the microstrip feeder port, and finally the deposition of metal ground plate 1.

[0049] The microwave topological photonic crystal metasurface antenna was tested using CST Microwave Studio simulation software. CST Studio Suite is a professional 3D electromagnetic field simulation software from Dassault Systèmes of Germany. It includes multiple electromagnetic numerical calculation methods: finite integration time domain method (FIT), finite difference time domain method (FDTD), finite element method (FEM), and method of moments (MoM). This example uses finite difference time domain method (FDTD).

[0050] The simulation steps of microwave topological photonic crystal metasurface antenna in CST are as follows:

[0051] (1) Establish model components, input size parameters, and construct the metal ground plate 69mm×69mm×0.1mm, fill it with the ideal electric conductor PEC in the material library, and the dielectric layer 69mm×69mm×1mm. Select Rogers RT-duroid 5580 from the material library ( =2.2) filling, topological photonic crystal 28.26mm×28.26mm×1.57mm, GaAs (lossless, =12.94) filling, and the rectangular metal frame and microstrip feed line are also set as PEC filling.

[0052] (2) A waveguide port is set at the other end of the microstrip feed, and the default excitation is adopted. In CST, the default excitation source for time domain solution is Gaussian pulse excitation, while the default excitation source for frequency domain solution is discrete cosine excitation. This embodiment adopts time domain Gaussian pulse excitation.

[0053] (3) Boundary processing can select PEC, open boundary and absorbing boundary conditions. In this embodiment, the entire structure boundary processing adopts absorbing boundary conditions, that is, perfect matching PML boundary to achieve the best effect.

[0054] (4) Set the frequency range to 17.4 to 18.6 GHz, select far-field in the field monitor, and set the frequency point that requires far-field analysis. After running, the output results can be viewed through the navigation tree on the left side of CST. CST can draw various parameter curves and can display the electromagnetic field changes of the system time step through snapshots to obtain parameters such as return loss, voltage standing wave ratio, radiation efficiency, input impedance and gain.

[0055] First, the topological photonic crystal eigenmode field is obtained by the CST eigenmode solver, and the data is exported to draw Figure 2 (c) shows the characteristic frequency scatter plot, and it is found that the frequency point of 17.995 GHz is located within the band gap and the corresponding eigenmode is a corner mode.

[0056] After simulation test, we get Figure 3 The return loss S11 parameter in the high frequency band is shown in the figure. It can be seen from the figure that the resonance point of the topological photonic crystal metasurface antenna in the high frequency band of 17.4~18.6GHz is 17.995GHz, which is consistent with the frequency of the topological protection mode in the band gap of the topological photonic crystal, and the minimum return loss is -46.05dB, which is less than the -26.05dB of the ordinary patch antenna of the same size.

[0057] The voltage standing wave ratio (VSWR) characteristics of topological photonic crystal metasurface antennas are as follows: Figure 4 As shown, it reaches 1.02, which is close to the ideal value of 1.

[0058] like Figure 5 As shown in the figure, the radiation efficiency of the topological photonic crystal metasurface antenna is greater than that of the ordinary patch antenna in the entire high-frequency band. In addition, subsequent measurements show that the maximum forward gain of the topological photonic crystal metasurface antenna in the high-frequency band is 8.88dBi, while that of the ordinary patch antenna is 6.43dBi, confirming that this structure can greatly improve the gain and radiation efficiency of the patch antenna.

[0059] like Figure 6 As shown, the far-field pattern of the phi=0 topological photonic crystal metasurface antenna at the high-frequency resonant frequency of 17.995 GHz ( Figure 6 (a)) and the far-field 17.644GHz radiation pattern of the ordinary patch antenna ( Figure 6 (b) By comparison, it can be seen that the topological photonic crystal metasurface antenna has better far-field directivity at the high-frequency resonance point, fewer stray lobes, greater gain, greater front-to-back suppression ratio, no main lobe beam offset, and the resonance frequency is the angular state frequency within the band gap of the topological photonic crystal, indicating that this radiation mode has stronger anti-interference and stability.

[0060] (5) Set the frequency range to 1.5 to 4.5 GHz and select far-field in the field monitor. Set the frequency point where far-field analysis is required. After running, the output results can be viewed in the navigation tree on the left side of CST. CST can draw various parameter curves and display the electromagnetic field changes of the system time step through snapshots to obtain parameters such as return loss, voltage standing wave ratio, radiation efficiency, input impedance, and gain.

[0061] After simulation test, we get Figure 7 The return loss S11 parameter in the low-frequency band is shown. The fundamental mode frequency of the topological photonic crystal metasurface antenna in the low-frequency band of 1.5 to 4.5 GHz is 3.988 GHz, and the minimum return loss is -11.5 dB, which is lower than the -4.26 dB of the fundamental mode frequency of 1.92 GHz of the ordinary patch antenna of the same size.

[0062] The voltage standing wave ratio (VSWR) characteristics of the fundamental mode frequency of the topological photonic crystal metasurface antenna are as follows: Figure 8 As shown, the value reaches 1.88, which is smaller than the 2.16 of the ordinary patch antenna.

[0063] like Figure 9 As shown in the figure, the radiation efficiency of 97.25% at the fundamental mode resonance point of 3.988 GHz is greater than the radiation efficiency of 83.07% at the fundamental mode resonance point of the ordinary patch antenna, which once again confirms that this structure can improve the gain and radiation efficiency of the patch antenna.

[0064] like Figure 10 As shown, the far-field pattern of the phi=0 topological photonic crystal metasurface antenna at the low-frequency fundamental mode resonant frequency of 3.988GHz ( Figure 10 (a)) and the far-field fundamental mode 1.92GHz radiation pattern of the ordinary patch antenna ( Figure 10 (b)) It can be seen from the comparison that the main lobe shape of the far-field radiation pattern of the fundamental mode resonant frequency of the topological photonic crystal metasurface antenna is basically the same as that of the ordinary patch antenna, but the main lobe gain of the former is larger, the former is 7.12dBi, and the latter is 6.28dBi, and the front-to-back suppression ratio of the topological photonic crystal antenna is larger.

[0065] After embedding the topological photonic crystal into the antenna, in addition to the current surge at the junction of the dielectric substrate and the rectangular metal frame, as with conventional patch antennas, current surges also occur at the edge of the interface between the rectangular metal frame and the photonic crystal due to distortion. This highly localizes the localized electromagnetic wave modes, thereby enhancing electromagnetic wave energy radiation and resulting in higher gain at a specific frequency. Furthermore, due to the presence of defect corner modes within the band gap of the topological photonic crystal, the electromagnetic wave radiation at that frequency is more resistant to interference, while the propagation of electromagnetic waves at other frequencies is suppressed. Consequently, compared to conventional patch antennas, the antenna exhibits a cleaner directivity pattern and greater mainlobe gain.

[0066] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0067] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A microwave topological photonic crystal metasurface antenna, characterized in that: include: A ground plate (1), a dielectric layer (2), and a topological photonic crystal (5) are sequentially arranged from bottom to top; and the device further comprises a rectangular metal frame (4) and a microstrip feed line (3), wherein the rectangular metal frame (4) is wrapped around the periphery of the topological photonic crystal (5), and the microstrip feed line (3) is connected to the rectangular metal frame (4); The topological photonic crystal (5) is composed of periodic photonic topological insulator cells, and the photonic topological insulator cells are divided into non-trivial domain cells and trivial domain cells; the non-trivial domain cells constitute a non-trivial domain, and the trivial domain cells constitute a trivial domain; the non-trivial domain is placed at the lower left corner of the topological photonic crystal (5), and the rest of the topological photonic crystal (5) is a trivial domain; The cross-sections of the photonic topological insulator cells are all square; there is a circular area in the center of the square cross-section of the trivial domain cell, and a rectangular strip extends from the upper, lower, left and right directions of the circular area to form a cross-shaped vein; the four corners of the square cross-section of the non-trivial domain cell are respectively provided with quarter circles, and the quarter circles on the four corners are connected by veins.

2. The microwave topological photonic crystal metasurface antenna according to claim 1, characterized in that: In the trivial domain cell, the cross-shaped veins and the circular area are filled with isotropic GaAs material, and the rest is air; in the non-trivial domain cell, the four quarter circles and the connected veins are filled with isotropic GaAs material, and the rest is air.

3. The microwave topological photonic crystal metasurface antenna according to claim 2, characterized in that: The GaAs material is one of triple-well resonance-phonon gallium arsenide or aluminum-containing gallium arsenide with a refractive index of 3.

6.

4. The microwave topological photonic crystal metasurface antenna according to claim 1, characterized in that: The non-trivial domain is composed of cells in a 4×4 two-dimensional array. The trivial domain is located above and to the lower right of the topological photonic crystal (5). The upper part is composed of cells in a 4×9 two-dimensional array, and the lower right part is composed of cells in a 5×4 two-dimensional array.

5. The microwave topological photonic crystal metasurface antenna according to claim 1, characterized in that: The ground plate (1) is made of copper and has a size of 69 mm × 69 mm × 0.1 mm; The dielectric layer (2) is made of Rogers RT-duroid 5580 and has a size of 69 mm × 69 mm × 1 mm; The rectangular metal frame (4) is made of copper and has a size of 52 mm × 52 mm × 1.57 mm; The microstrip feed line (3) is made of copper and has a size of 0.95 mm × 8.5 mm × 1.57 mm.

6. The microwave topological photonic crystal metasurface antenna according to claim 1, characterized in that: The characteristic size of the topological photonic crystal (5) is 28.26 mm; the characteristic size of the photonic topological insulator cell is 3.14 mm; In the mediocre domain cell, the radius of the circle is 1.11 mm, the width of the cross vein is 0.314 mm, and the length is 3.14 mm; in the non-trivial domain cell, the radius of the quarter circle is 1.11 mm, the width of the edge vein is 0.157 mm, and the length is 3.14 mm.

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