薄膜体声波谐振器的有限元仿真

Finite Element Simulation of a Film Bulk Acoustic Resonator

随着5G通信技术的日益发展,对通信频段的要求越来越高。传统的射频滤波器受结构和性能的限制,不能满足高频通信的要求。薄膜体声波谐振器(FBAR)作为一种新型的MEMS器件,很好地适应了无线通信系统的更新换代,使FBAR技术成为通信领域的研究热点之一。本文以COMSOLMultiphysics软件为基础,对FBAR谐振元件进行有限元仿真,分析其压电耦合特性、模态特性、谐振特性等。设计的谐振单元,谐振频率在工信部规划的5G通信频段标准(3.4 GHz-3.6 GHz)以内。同时引入完美匹配层(PML)减少寄生共振,更符合实际工艺制备的FBAR的共振特性。实验仿真结果表明,谐振频段在3.510 GHz-3.564 GHz,满足5G通信系统对频段的要求。当谐振位移形式变量满足AlN压电材料的变形范围,计算FBAR的主要性能指标,建立了一种基于COMSOL Multiphysics软件对FBAR的物理结构建模及相关特性研究的实验方法。

With the increasingly development of 5G communication technology, the demand of communication frequency band is getting higher and higher. Traditional RF filters cannot meet the requirements of high-frequency communication due to the constraints of structure and performance. As a new MEMS device, thin film bulk acoustic resonator (FBAR) is a good match for the update of wireless communication system, making FBAR technology become one of the research hotspots in the field of communication. Based on COMSOL Multiphysics software, the finite element simulation of FBAR resonant element is carried out in this paper to analyze its piezoelectric coupling characteristics, modal characteristics, resonance characteristics, etc. It designs resonant units which resonant frequency within the standard of 5G communication frequency band (3.4 GHz-3.6 GHz) projected by the ministry of industry and information technology. At the same time, the introduction of the perfect matching layer (PML) to reduce the parasitic resonance is more consistent with the resonance characteristics of FBAR prepared by the actual process. The experimental simulation results show that the resonant frequency band is within the range of 3.510 GHz-3.564 GHz, which meets the requirements of 5G communication system for frequency band. When the resonant displacement form variable meets the deformation range of AlN piezoelectric material,calculating the main performance indexes of FBAR and establishing an experimental method based on COMSOL Multiphysics software to study the physical structure modeling and related characteristics of FBAR.