折叠梁平面角对电容式RF MEMS开关性能的影响

Effect of plane angle of serpentine spring on characteristics of capacitive RF MEMS switch

低驱动电压电容式RF MEMS开关采用弹性拆叠梁支撑可变电容活动极板,使开关弹性结构具有很小的弹性系数,但也降低了开关的一阶模态谐振频率,致使开关无法获得较高的开关速度。提出了通过调整弹性折叠梁平面角微调弹性结构弹性系数的方法,在保证开关具有低驱动电压的同时,尽可能提高弹性结构的一阶模态谐振频率。仅改变弹性折叠梁平面角的大小,对其分别为0°,45°,90°的具体开关结构,应用MEMS CAD软件CoventorWare进行机电耦合仿真,定性分析了弹性折叠梁平面角对微结构弹性系数的影响。仿真结果表明:改变弹性折叠梁平面角大小,可以微调电容式RF MEMS开关的驱动电压和一阶模态谐振频率。

The flexible serpentine spring is widely used as the variable capacitor movable plate＇ s support structure of the capacitive RF MEMS with the characteristic of low actuation voltage. The reason is the low elastic coefficient of flexible serpentine spring makes the compliant structure＇ s elastic coefficient of the switch very low. Low compliant structure＇ s elastic coefficient also leads to the low switch＇ s first model resonance frequency in dynamic situation. The disadvantage of the low switch＇ s first model resonance frequency is that it can＇ t make the switch to switch high speed. The way of adjusting the compliant structure＇ s elastic coefficient through changing the flexible serpentine spring＇ s plane angle is put forward. The purpose of the way is to improve the compliant structure＇ s first model resonance frequency as much as possible and also the switch＇ s actuation voltage is also kept low. MEMS CAD software CoventorWare is used to simulate the mechanical and electrical characteristics of the capacitive RF MEMS switches with different flexible serpentine spring＇ s plane angle, but the other structure parameters of the switch are not changed. The respective flexible serpentine spring＇ s plane angles are 0° ,45° and 90°. How effect of flexible serpentine spring＇ s plane angle on the micro structure＇ s elastic coefficient is qualitatively analyzed. The results demonstrate that the actuation voltage and the first model resonance frequency of the capacitive RF MEMS switch can be adjusted by changing the flexible serpentine spring＇ s plane angle.