Study Of Thermal Failure Physical Of BAW Filters At High Power Level

Filter design is very important and has technical barriers in RF front-end design.BAW filters based on Bulk Acoustic Wave(BAW)technology are new development direction of micro-filters.However,high frequency,large bandwidth and high power are the technical difficulties of the current development of BAW filters.High power will cause serious heating of the device,and miniaturization means poor heat dissipation.High temperature of the device will lead to performance failure or even structural failure and burn.Aiming at the technical problem of high power,this paper studies the performance of BAW filters at high power.The specific work includes:1、 In order to simulate the self-heating effects of BAW resonators and filters,a BAW device simulation model based on finite element is established.The model includes electrical and thermal multiple physical fields,and the distributed dissipated power of BAW devices can be calculated.The electrical and thermal coupling solution can be used to obtain the self-heating temperature distribution cloud map of BAW filters.2、 For the thermal performance failure of BAW filters,a thermal-acoustic-electrical model is established,and the temperature dependence of material parameters is used to simulate the electrical performance of BAW filters at self-heating temperature.The effects of temperature on frequency response of BAW filters are studied by using this model.3、 Based on the structure damage principle of BAW devices,a simulation method of the structure failure of BAW devices is proposed,which can effectively prove that thermal stress and electrode surface charge accumulation can cause the structure failure of BAW devices,and can judge whether the structure failure is based on this.4、 Taking a BAW filter as an example,the influence of input power on temperature,the influence of ambient temperature on filter frequency and insertion loss,and the self-heating frequency point test are completed,which verifies the feasibility of the simulation method of self-heating effects of BAW filters.