See-saw Type RF MEMS Switch with Fine Gap Vertical Comb

This paper reports RF MEMS switch that has low actuation voltage and high isolation characteristics. We propose see-saw type RF MEMS switch based on a single crystalline silicon structure with fine gap vertical comb. Low voltage actuation and high isolation characteristics are key features to be solved in electrostatic RF switch design. Since these parameters in the conventional parallel plate MEMS switch design are in trade-off relation, both requirements cannot be met simultaneously. In vertical comb design, however, the actuation voltage is independent to the vertical separation distance between the contact electrodes. Then, we can design the large separation distance between contact electrodes to get high isolation. We have designed and fabricated a RF MEMS switch which has -46 dB isolation loss at 5 GHz, -0.9 dB insertion loss at 5 GHz and 40 V operation voltage.