体声波滤波器功率容量的评估方法

Evaluation Method of Power Handling of Bulk Acoustic Wave Filter

为了解决在体声波(BAW)滤波器的设计中对功率容量指标考虑欠缺的问题,提出了一种BAW滤波器功率容量的评估方法。首先通过BAW滤波器在特定输入功率和环境温度下的声-电磁-热多物理场仿真,得到在自热效应下各单元谐振器的叠层温度平均值;然后将叠层温度平均值作为设计参量引入到Mason模型中,搭建含温度参量的Mason(T)(T为温度)模型;最后在Mason(T)模型中模拟BAW滤波器的传输曲线,根据在全温度范围内各项性能指标是否超标来评估BAW滤波器的功率容量水平。仿真结果表明,在输入功率为23 dBm、环境温度为全温度范围(-25~85℃)时,BAW滤波器的各项指标均未超标;在输入功率为30 dBm、环境温度为30℃时,BAW滤波器的上频带插入损耗和带外抑制已超标,性能出现明显退化。

In order to solve the problem of insufficient consideration of power handling in the design of bulk acoustic wave(BAW)filters,a method for evaluating the power handling of BAW filters is proposed.First,the average temperature value of each stack of the unit resonator under the self-heating effect is obtained by the acoustic-electromagnetic-thermal multi-physics field simulation of the BAW filter at a specific input power and ambient temperature.Then,the average temperature values are introduced as design parameters into the Mason model to eastablish the Mason(T)model with temperature parameters.Finally,the transmission curve of the BAW filter is simulated in the Mason(T)model,and the power handling of BAW filter is evaluated according to whether all the specifications exceed the standard in the whole temperature range.The simulation results of the case filter show that all the parameters of the BAW filter do not exceed the standard when the input power is 23 dBm and the ambient temperature is in the whole temperature range(-25~85℃).However,when the input power is 30 dBm and the ambient temperature is 30℃,the upper band insertion loss and out-of-band rejection of the BAW filter have exceeded the standard,and the performance is significantly degraded.