体声波双工器的优化设计方法

体声波(BAW)双工器中Rx滤波器对Tx滤波器的负载效应,会使Tx滤波器的插入损耗性能退化而带外抑制性能过剩,进而使得BAW双工器性能不佳。为了解决这一问题,提出了一种BAW双工器的优化设计方法。设置BAW双工器中Tx滤波器的串联薄膜体声波谐振器(FBAR)单元谐振区面积,及并联FBAR单元与串联FBAR单元谐振区面积比值为两组优化变量,通过牺牲Tx滤波器过剩带外抑制性能的方式,采用基于梯度的优化算法计算得到了两组优化变量的最终取值。以一个工作在FDD-LTE band 7的BAW双工器优化设计案例展示了该方法的应用流程。优化设计结果的仿真验证表明,Tx滤波器的插入损耗性能从2dB提升至1.1dB,带内波动性能从1dB提升至0.3dB。由此验证了该方法的可行性。

Design Optimization Method for Bulk Acoustic Wave Duplexer

The load effect of Rx filter on Tx filter in Bulk acoustic wave (BAW) duplexer can bring about the degradation of the insertion loss performance and can cause performance surplus of the band rejection of Tx filter. In order to solve this problem, a design optimization method of BAW duplexer was proposed in this work. The resonance area of series FBAR and ratio of resonance area of parallel FBAR to series FBAR were set up as two groups of optimization variables. By sacrificing the excess out band rejection of Tx filter, the gradient base optimization algorithm was used to obtain the final values of the two groups of the optimization variables. The application progress of the proposed method was showed by an optimized design example of BAW deplexer in FDD LTE band 7. The simulation result showed that the insertion loss of Tx filter was improved from 2 dB to 1.1 dB, and the ripple in band was improved from 1 dB to 0.3 dB, which verifies the feasility of this method.