RF MEMS switch has been paid great attention due to its excellent RF performance. A surface-micromachined microwave switch with push-pull configuration has been proposed and demonstrated. A low actuation voltage has been achieved by means of torsion springs and leverage. RF characteristics of the switch are simulated with the RF model. The actuation voltage is calculated according to the dimension of the switch. Au is used as a main structure layer due to its low shear modulus and as a contact electrode due to its high conductivity and anti-oxidation property. Photoresist is used as a sacrificial layer due to its high etching selectivity to the structure materials. Dry etching is utilized at the release step to prevent the stiction problem. Minimum 5V of the actuation voltage is measured. Insertion loss is measured as < 1dB up to 2GHz. Isolation is measured as > 35dB up to 2GHz. Isolation is about 10dB improved by the push-pull configuration. The switching time is measured as 0.66msec.
As the applications of the RF MEMS switch, DT switch and DPDT switch are proposed. The DT switch is a new functional device, dividing input signal to two output ports or transmitting the input signal to one output port. The proposed DPDT switch has the merits of simple configuration and extendibility. The performances of th DT switch and the DPDT switch are verified by the simulation. High efficiency balanced amplifier using the DT switches is proposed. Even without DC current switching, maximum 10% improvement of PAE is estimated in class AB amplifier.
