Adjustable missing type topological insulator structure capable of improving SAW wave resonator performance

Abstract

The utility model discloses an adjustable missing type topological insulator structure capable of improving the performance of an SAW wave resonator, which is an array formed by a plurality of unit cell structures, and each unit cell structure comprises a first conical column and a second conical column on the upper layer and a semi-infinite quadrangular prism on the lower layer. Four boss planes are arranged on the periphery of the lower quadrangular prism; the array is in two-dimensional periodic arrangement, semi-infinite quadrangular prisms are connected through boss planes in the two-dimensional x direction and the two-dimensional y direction, and a hexagonal structure with a semi-infinite substrate is formed through periodic distribution in the x direction and the y direction. According to the utility model, the lattice symmetry of the system is broken through flexibly changing the missing part of the micro-column, and the high performance of the SAW resonator is realized by utilizing the sound propagation characteristic of the topological insulator and the low loss, high robustness and high flexibility of sound wave transmission under a broadband.

Description

Technical Field

[0001] The utility model belongs to the technical field of surface acoustic wave resonators, and in particular relates to an adjustable missing type topological insulator structure capable of improving the performance of a SAW wave resonator. Background Art

[0002] Since the advent of surface acoustic wave (SAW), various SAW devices have been widely used in radar, communication, navigation and other fields. In the future, surface acoustic wave filters will inevitably develop towards high performance (such as high quality factor Q, low insertion loss, high sensitivity, etc.) to meet the needs of the daily intelligent market, so related research on improving the performance of surface acoustic wave devices has become crucial.

[0003] Phononic crystals refer to artificial structures with periodic arrangement of elastic parameters and mass density in space. Phononic crystals have been widely used in isolating noise and vibration, mechanical filters and waveguides. In recent years, various topological states in electronic systems have been the subject of intensive research in condensed matter physics. Since the existence of topological properties depends largely on the band structure itself, the topological states and features found in electronic systems can also be realized in bosonic systems, leading to the emergence of topological photonics, mechanics and acoustics. An underlying motivation behind these explorations is that this topological property provides an unparalleled transmission mechanism with backscattering suppression, which revolutionizes the reduction of transmission losses, arbitrarily designed transmission paths and defect robustness in device processing in any system. The excellent properties of topological insulators, such as unidirectional waveguides, low-loss transmission and defect immunity, make them widely used in wave control and acoustic transmission.

[0004] The wave control properties of the topological insulator are applied to the surface acoustic waves excited by the interdigital transducer (IDT) in the SAW resonator, and high-transmittance transmission of the resonator is achieved through the surface acoustic wave waveguide.

[0005] In 2021, Zhang et al. introduced topological insulators into SAW resonators, changed the density of the copper pillars in the array between the IDTs on both sides to realize SAW topological insulators, constructed topological interfaces on the SAW resonator, and improved the overall transmittance. However, the lattice asymmetry was not achieved by changing the structure of the copper pillars themselves, and the resulting band gap was narrow, resulting in a small resonator operating bandwidth.

[0006] In 2022, Wang et al. changed the radius of the honeycomb microcolumns and constructed two SAW topological insulators with different properties, which greatly improved the transmittance of the SAW resonator. However, by only changing the single parameter of the microcolumn, they did not consider the missing defects of the microcolumn itself, and the control of the SAW topological insulator band gap was not flexible enough. In addition, the SAW topological insulator band gap was narrow, resulting in poor adaptability of the SAW resonator. Summary of the invention

[0007] In order to overcome the above technical problems, the purpose of the utility model is to provide an adjustable missing topological insulator structure that can improve the performance of the SAW wave resonator. By flexibly changing the missing part of the microcolumn, the lattice symmetry of the system is broken, and the sound propagation characteristics of the topological insulator are utilized to achieve low loss, high robustness and high flexibility of sound wave transmission under a wide bandwidth, thereby achieving high performance of the SAW resonator.

[0008] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0009] An adjustable missing topological insulator structure capable of improving the performance of a SAW wave resonator is an array composed of a plurality of unit cell structures, each unit cell structure comprising two conical columns 1 and 2 on the upper layer and a semi-infinite quadrangular column on the lower layer; the quadrangular column on the lower layer has four boss planes on its periphery;

[0010] The array is a two-dimensional periodic arrangement, and the semi-infinite tetrahedral prisms are connected by boss planes along the two-dimensional x and y directions, and are periodically distributed in the x and y directions to form a hexagonal structure with a semi-infinite base.

[0011] The second conical cylinder is obtained by taking the radius in the y direction as the reference and the missing part angle of 6 μm in height with the first conical cylinder.

[0012] The degree of the missing part of the second conical column can be adjusted arbitrarily within the range of 10 to 350 degrees.

[0013] The lower layer of semi-infinite quadrangular prism is formed by stretching rhombus faces with four sides of equal width.

[0014] The conical column is obtained by inverting a cone.

[0015] The first conical column and the second conical column with a missing part are located at two trisection points of the diagonal line of the long rhombus face of the quadrangular prism.

[0016] The first geometrical parameter of the conical cylinder is that the upper circle radius is 5 μm, the lower circle radius is 4.15 μm, and the height is 8 μm.

[0017] The two geometric parameters of the missing conical cylinder are: the upper circle radius is 5 μm, the lower circle radius is 4.15 μm, the height is 8 μm, and the vertical height of the missing part is 6 μm.

[0018] The geometric parameters of the rhombus surface of the lower semi-infinite quadrangular prism are that the acute angle is 60° and the long diagonal is 45 μm.

[0019] The materials used for the conical column 1 and the conical column 2 with a defect are copper, and the material used for the lower semi-infinite quadrangular prism 3 is lithium niobate, and the height is 150 μm.

[0020] The structure of the conical cylinder 1 is different from that of the conical cylinder 2 with a missing portion. By missing the conical cylinder 2 at different angles, the strength of the asymmetry of the system lattice can be flexibly controlled, thereby forming a topological insulator with better topological properties.

[0021] Beneficial effects of the utility model:

[0022] The utility model can flexibly control the band gap of the topological insulator energy band by flexibly controlling the amount of missing parts. Therefore, a wider band gap than other surface acoustic wave topological insulators can be obtained. Then, the waveguide characteristics of the topological insulator are used to regulate the surface waves excited by the surface acoustic wave resonator under ultra-wide frequency band, realizing low loss and high flexibility in verifying waveguide transmission.

[0023] The application of the adjustable missing topological insulator structure of the utility model in the resonator can effectively control the transmission of acoustic waves in the surface acoustic wave resonator. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the unit cell structure of the utility model, where the angle of the missing part is 90°.

[0025] Figure 2 It is a two-dimensional arrangement diagram of the utility model.

[0026] Figure 3 This is a schematic diagram of a 180° missing cylinder of the adjustable missing topological insulator of the utility model.

[0027] Figure 4 This is a schematic diagram of a 270° missing cylinder of the adjustable missing topological insulator of the utility model.

[0028] Figure 5 This is the adjustable missing topological insulator of the utility model, with a missing 90° structural energy band diagram.

[0029] Figure 6 This is the adjustable missing topological insulator of the utility model, with a missing 180° structural energy band diagram.

[0030] Figure 7 This is the adjustable missing topological insulator of the utility model, with a missing 270° structural energy band diagram.

[0031] Figure 8This is a simulated transmission displacement diagram of the utility model's adjustable missing topological insulator applied to a SAW resonator.

[0032] Fig. 9 This is a curve diagram of the S21 (insertion loss) value of the utility model's adjustable missing topological insulator, in which a structure missing 270° is applied to a resonator at 66-76MHz.

[0033] Fig.10 The figure shows the sensitivity comparison of the adjustable missing topological insulator structure of the utility model before and after being applied on the resonator. DETAILED DESCRIPTION

[0034] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0035] like Figure 1 , Figure 2 As shown, an adjustable missing topological insulator structure that can improve the performance of a SAW wave resonator is an array composed of a plurality of unit cell structures, each unit cell structure includes two conical columns 1, a conical column 2, and a lower semi-infinite quadrangular prism 3; the lower quadrangular prism has four boss planes 4 on its periphery;

[0036] The array is a two-dimensional periodic arrangement, and the semi-infinite quadrangular prisms 3 are connected by boss planes 4 along the two-dimensional x and y directions, and are periodically distributed in the x and y directions to form a hexagonal structure with a semi-infinite base.

[0037] The conical cylinder 2 is obtained by taking the radius in the y direction as the reference and the missing part angle of 6 μm in height with respect to the conical cylinder 1.

[0038] The degree of the missing part of the conical column 2 can be adjusted arbitrarily within the range of 10 to 350 degrees.

[0039] The lower layer semi-infinite quadrangular prism 3 is formed by stretching a rhombus surface with four sides of equal width.

[0040] The conical column 1 is obtained by inverting a cone.

[0041] The conical column 1 and the conical column 2 with a missing part 2 are located at two trisection points of the diagonal line of the rhombus face of the quadrangular prism 3.

[0042] The geometric parameters of the conical cylinder 1 are that the upper circle radius is 5 μm, the lower circle radius is 4.15 μm, and the height is 8 μm.

[0043] The geometric parameters of the missing conical column 2 are: the upper circle radius is 5 μm, the lower circle radius is 4.15 μm, the height is 8 μm, and the vertical height of the missing part is 6 μm.

[0044] The geometric parameters of the rhombus surface of the lower semi-infinite quadrangular prism 3 are that the acute angle is 60° and the long diagonal is 45 μm.

[0045] The materials used for the conical column 1 and the conical column 2 with a defect are copper, and the material used for the lower semi-infinite quadrangular prism 3 is lithium niobate, and the height is 150 μm.

[0046] The conical cylinder 1 is different from the structure with the missing conical cylinder 2 2. The missing conical cylinder 2 2 is missing at different angles, which can flexibly control the strength of the asymmetry of the system lattice, thereby forming a topological insulator with better topological properties.

[0047] The utility model discloses an implementation method of an adjustable missing topological insulator structure. The upper two micro-column structures are arranged in several periods connected by a prism base along the x and y directions. The adjustable missing topological insulator structure is composed of two upper conical columns 1, 2 and a lower base. The geometric parameters of the conical column 1 are an upper circle radius of 5 μm, a lower circle radius of 4.15 μm and a height of 8 μm. The conical column 2 is a missing part on the basis of the conical column 1, and the vertical height of the missing part is 6 μm. Figure 1 The middle is a schematic diagram of the structure with 90° missing. The diagonal length of the base rhombus face is 45μm, and the prism height is 150μm. The materials used are copper for the conical column and lithium niobate for the quadrangular prism base. The specific material parameters are as follows:

[0048] Material <![CDATA[Density kg / m 3 > Young's modulus μ / Pa Poisson's ratio copper 8930 <![CDATA[8.9x10 10 ]]> 0.33 Material <![CDATA[Density kg / m 3 > Relative dielectric constant Speed ​​of sound m / s Lithium Niobate 4700 43.6,43.6,29.16 3848

[0049] Figure 3 and Figure 4 This is a schematic diagram of the structure of a conical column 2 with 180° and 270° missing.

[0050] from Figure 5 It can be seen from the energy band diagram that when the missing part is at 90°, this tunable missing topological insulator can open the Dirac point and produce a wide band gap of 66MHz to 69.5MHz.

[0051] from Figure 6 It can be seen from the energy band diagram that when the missing part is 180°, this adjustable missing topological insulator can open the Dirac point and produce a wide band gap of 66MHz to 73.7MHz.

[0052] from Figure 7 It can be seen from the energy band diagram that when the missing part is at 270°, this tunable missing topological insulator can open the Dirac point and produce a wide band gap of 66MHz to 78.5MHz.

[0053] from Figure 8It can be seen from the simulated transmission displacement diagram that under the excitation on the left, the acoustic wave propagates forward along the topological interface in the topological insulator resonator, and the backscattering is suppressed.

[0054] from Fig. 9 It can be seen from the S21 parameter curve that in the range of about 69MHz to 75MHz, the resonator loss is lower than that at other frequencies.

[0055] from Fig.10 It can be seen from the sensitivity diagram that the sensitivity of the resonator under the action of the tunable missing topological insulator is improved to 12.48 times that of the original bare device.

[0056] It can be seen that by adopting the adjustable missing topological insulator structure of the utility model, a high-sensitivity resonator can be realized at a specific frequency and the sound wave transmission of the surface acoustic wave resonator can be reduced to a certain extent.

[0057] Therefore, the adjustable missing topological insulator structure of the utility model can be applied to the fields of surface acoustic waves and surface acoustic wave resonators, and in particular to the performance of surface acoustic wave resonators, and can reduce the accuracy of transmission loss of resonator devices and improve the sensitivity of the devices.

[0058] The working principle of this utility model:

[0059] A straight-line channel composed of tunable missing topological insulators is placed on the SAW resonator. The backscattering suppression characteristics of topological insulators are used to localize the energy at the interface and propagate it strictly forward. Figure 8 Therefore, the transmission efficiency of the SAW resonator is improved and the transmission loss is reduced.

[0060] Therefore, the petal-shaped topological insulator structure of the utility model can be applied to the fields of surface acoustic waves and surface acoustic wave resonators, and in particular to the performance of surface acoustic wave resonators, and can reduce the accuracy of transmission loss of resonator devices and improve the sensitivity of the devices.

Claims

1. A tunable defect-type topological insulator structure that can improve the performance of SAW wave resonators, It is characterized in that The array is composed of a plurality of unit cell structures, each unit cell structure comprises two cone columns 1 (1) and cone column 2 (2) in the upper layer and a semi-infinite quadrangular prism (3) in the lower layer; the periphery of the semi-infinite quadrangular prism (3) in the lower layer has four boss planes (4); The array is a two-dimensional periodic arrangement, and the semi-infinite tetrahedral prisms (3) are connected by boss planes (4) along the two-dimensional x and y directions, and are periodically distributed in the x and y directions to form a hexagonal structure with a semi-infinite base.

2. The adjustable missing topological insulator structure for improving the performance of a SAW wave resonator according to claim 1, It is characterized in that The conical cylinder 2 (2) is obtained by making an angle with the conical cylinder 1 (1) with the radius in the y direction as the reference and the missing part of the height being 6 μm.

3. The adjustable missing topological insulator structure for improving the performance of a SAW wave resonator according to claim 1, It is characterized in that The degree of the missing part of the conical column 2 (2) can be adjusted arbitrarily within the range of 10 to 350 degrees.

4. The adjustable missing topological insulator structure for improving the performance of a SAW wave resonator according to claim 1, It is characterized in that The lower layer semi-infinite quadrangular prism (3) is formed by stretching a rhombus surface with four sides of equal width.

5. The adjustable missing topological insulator structure capable of improving the performance of a SAW wave resonator according to claim 1, It is characterized in that The conical column 1 (1) is obtained by inverting a cone.

6. The adjustable missing topological insulator structure for improving the performance of a SAW wave resonator according to claim 1, It is characterized in that The geometric parameters of the conical cylinder 1 (1) are that the upper circle radius is 5 μm, the lower circle radius is 4.15 μm, and the height is 8 μm.

7. The tunable missing topological insulator structure for improving SAW wave resonator performance according to claim 1, It is characterized in that The conical column one (1) and the conical column two (2) with a missing portion are located at two trisection points of the diagonal line of the rhombus face of the quadrangular prism (3).

8. The adjustable missing topological insulator structure capable of improving the performance of a SAW wave resonator according to claim 7, It is characterized in that The geometric parameters of the missing conical cylinder 2 (2) are that the upper circle radius is 5 μm, the lower circle radius is 4.15 μm, the height is 8 μm, and the vertical height of the missing part is 6 μm.

9. The tunable missing topological insulator structure for improving SAW wave resonator performance according to claim 1, It is characterized in that The geometric parameters of the rhombus surface of the lower layer semi-infinite quadrangular prism (3) are that the acute angle is 60° and the long diagonal is 45 μm.

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