5G通信技术对射频滤波器提出了越来越高的要求，包括更大的带宽、更稳定的性能、更小的尺寸、更高的频率。成本低、体积小的声表面波（SAW）滤波器是射频滤波器的首选，但传统的SAW技术已无法满足5G通信的需求。为了实现SAW滤波器的5G频段应用，本文从材料的基本性能出发，通过材料设计和结构优化，调控器件内部的声电效应，提升SAW器件的性能，助力5G技术的发展。调控声电耦合及声传播过程以增大滤波器带宽。利用SiC的高声速和15°Y-X LiNbO3的强声电耦合特性，构建了绝缘体压电层复合衬底（POI）材料15°Y-X LiNbO3/SiO2/SiC，既提高了器件的声电转化效率，也降低了其声传播能量损耗。优化调控了谐振器之间的电耦合，采用梯形结构设计制备了31%的超大带宽滤波器。该带宽达到常规大带宽水平的3倍，且超过所有5G通信Sub-6GHz频段的带宽。调控声传播介质以增强器件稳定性。利用SiC的大弹性常数、低热膨胀系数和高热导率，构建了热膨胀小的双层POI衬底材料LiTaO3/SiC，减小了声波波长随温度的变化，加快了散热。在该衬底上设计制备了可覆盖n41全频段的滤波器，其温漂仅?6.53ppm/°C，是传统体材料滤波器的1/6；其寿命达传统滤波器的11.3倍。针对大带宽器件，构建了基于POI衬底材料的多层结构SiO2/电极/LiNbO3/SiO2/高声速衬底，减小了声速随温度的变化，保证了大带宽特性，解决了漏波和杂波问题。设计制备了基于该结构的滤波器，同时实现了低插损、低温漂、大带宽。调控声电场分布以探索超小尺寸免封装器件。利用AlN和Si的高声速，结合SiO2的温度补偿特性，构建了器件结构AlN/电极/ZnO/SiO2/Si，将声波限制在ZnO和SiO2中，经过仿真研究，实现了近零温漂的免封装器件。利用SiNx的高声速，构建了器件结构SiNx/SiO2/电极/15°Y-X LiNbO3，将声电场控制在LiNbO3上界面，设计制备了免封装滤波器，尺寸仅0.695×0.490×0.122mm3，远小于常规封装尺寸。调控声激励介质以提高器件频率。将平面式叉指分为两层，设计了三维排布式叉指换能器，仿真计算了应用该设计的四种器件，均实现了相同工艺条件下，波长减小近一半，频率提升1倍左右。利用SiO2和SiNx材料的声速差异，构建了表面异质结构SiO2/SiNx，既抑制了水平剪切波的自然漏波特性，也避免了声速损耗，设计制备了具有该结构的器件，实现了声速提升50%左右，频率提升达50%左右。综上所述，本文显著拓宽了SAW滤波器在5G通信中的可应用范围。

5G wireless system sets high requirements to RF filters: larger bandwidths, more stable performances, smaller sizes, and higher frequencies. Surface acoustic wave (SAW) filters, which are usually low-cost and miniature, are the first choice for RF filters. Nevertheless, traditional SAW technologies are unable to keep up with the demand of 5G. To help apply SAW devices into 5G communication bands, starting from the basic performances of materials, this thesis modulates acoustoelectric effect inside devices by material design and structural optimization, and then enhances the performances and promotes the development of 5G technology.Modulating acoustoelectric coupling and acoustic propagation to enlarge bandwidth. This thesis utilizes the high acoustic velocity of SiC and the large acoustoelectric coupling property of 15°Y-X LiNbO3. Piezoelectric-on-insulator (POI) bonded wafer 15°Y-X LiNbO3/SiO2/SiC is structured, realizing higher efficiency of acoustoelectric conversion and less energy loss during acoustic propagation. The electrical coupling between the resonators in the filters is modulated, and an ultra-wideband SAW filter with the bandwidth of 31% and trapezoidal frame is designed and fabricated. This bandwidth reaches 3 times the level of normal large bandwidth, and is larger than all the full-band frequency bands among sub-6 GHz in 5G communication.Modulating the media of acoustic propagation to enhance the stability of devices. The large elastic constants, small thermal expansion coefficients, and large thermal conductivity of SiC are utilized, and bilayer POI bonded wafer LiTaO3/SiC with small thermal expansion is structured, reducing the change of acoustic wavelength with the variation of temperature and accelerating heat disspation. Filters based on this bonded wafer are designed and fabricated, covering full-band n41. The temperature coefficient of frequency is only ?6.53ppm/°C which is one-sixth of that on traditional bulk LiTaO3. Meanwhile, the lifetime is prolonged to 11.3 times the filters based on bulk LiTaO3. Aiming at wideband devices, this thesis designs multilayered structure SiO2/electrodes/LiNbO3/SiO2/high-speed substrate, which can reduce the change of acoustic velocity with the variation of temperature, ensure the property of large bandwidth, and solve the problem of leaky wave or spurious wave. SAW filters based on this structure are designed and fabricated. Low loss, low drift of frequency, and large bandwidth are achieved simultaneously.Modulating the distribution of acoustoelectric field to explore packageless devices with ultra-small sizes. This thesis utilizes AlN thin film and Si substrate with high acoustic velocities, and designs multilayered structure AlN/electrodes/ZnO/SiO2/Si. The acoustic wave is confined inside the ZnO and SiO2 layer. After the simulation study, this thesis realizes packageless devices with near-zero temperature coefficient. This thesis uses high-acoustic-velocity SiNx, and proposes structure SiNx/SiO2/Cu electrodes/15°Y-X LiNbO3. The acoustoelectric field is confined around the upper interface of LiNbO3, and packageless filters based on the structure are fabricated. An ultra-small size of the filters is realized, 0.695×0.490×0.122mm3, which is much smaller than the present common package sizes.Modulating the media of acoustic excitation to improve frequency. Separating a set of interdigital transducers into two layers, this thesis designs 3D layout of interdigital transducers, and simulates four kinds of devices with the design. This thesis reduces the wavelength to about a half under the same critical resolution of lithography, and then increases the frequency by about 100%. Utilizing the heterogeneity of SiO2 and SiNx, this thesis designs surface heterostructure SiO2/SiNx which suppresses the leaky nature of shear-horizontal wave and avoids the loss acoustic velocity. Devices with the heterostructure are designed and fabricated. The acoustic velocity is now approximately 50% larger and then the frequency is about 50% higher.To sum up, this thesis broadens the application sphere of SAW filters in 5G communication.