Determination of intermodulation distortion in a MEMS microswitch

This paper presents a method for predicting the size of intermodulation products due to contact heating in a contact type MEMS microswitch. The primary origin of intermodulation distortion in the microswitch is the variation of the switch resistance at the difference frequency due to the temperature dependence of the resistivity and thermal conductivity of materials in the switch. This varying resistance modulates the high frequency signals, resulting in intermodulation products. The resistance of the switch was modeled using a finite element simulation that predicted resistance variations at a variety of frequencies and power levels. This procedure leads to IIP3 predictions on the order of +64.8 dBm for this switch. This result corresponds to a sideband power of -73.3 dBc for a 1 W input.