高Q值横向激发体声波谐振器的设计与制备

随着5G移动通信时代的发展,射频前端(RF front-ends)的滤波和信号处理迫切需要高频大带宽的声学谐振器。横向激发体声波谐振器(XBAR)具有超高的工作频率和超大的机电耦合系数(k²),但其品质因数(Q)值不高,阻碍了其在射频前端中的应用。该文提出了一种基于ZY切铌酸锂(LiNbO₃)的XBAR谐振器,通过有限元(FEM)仿真对谐振器进行了优化设计,并在微机电系统(MEMS)工艺下对谐振器进行加工。该文所制备的横向激发体声波谐振器A₁模式的谐振频率为4.72 GHz,k²=26.9%,Q_{3 dB}为384,温度频率漂移系数为-60.5×10^-6/℃。A₃模式的谐振频率为13.5 GHz,k²=4.4%。

Design and Preparation of High-Q XBARs

With the adventof the fifth generation(5G) mobile communication era, there is an urgent demand for high-frequency and large-bandwidth acoustic resonators for RF front-end filtering and signal processing. The laterally excited bulk wave resonator (XBAR) has garnered significant attention from researchers due to its ultra-high operating frequency and substantial electromechanical coupling coefficient(k²). However, XBARs suffer from alow quality factor (Q), impeding their application in RF front-ends. This paper proposes XBARs based on ZY-cut lithium niobate (LiNbO₃). Resonator designs were optimized using the finite element method, and resonators were fabricated using micro-electro-mechanical systems. The resulting XBAR exhibiteda resonant frequency of 4.72 GHz, k² value of 26.9%, Q_{3 dB} value of 384, and temperature coefficient of frequency of -60.5×10^-6/℃ for the A1 mode, along with a resonant frequency of 13.5 GHzand k² value of 4.4% for the A₃ mode.