Study on low voltage actuated MEMS rf capacitive switches

We report the study on the MEMS rf switches with low actuated voltage. The switch structure has been optimized by the calculation on the dependence of actuated voltage on the Young’s modulus of membrane materials and geometrical sizes. Compared with gold material, AlSi 0.04 is a good movable film material having lower actuated voltage (5 V). The switches array is made on the coplanar waveguide (CPW) transmission lines, which were fabricated on quartz, high resistivity (>2 kΩ cm) silicon and porous silicon substrates respectively. The pull-in voltage of the variable capacitor was below 20 V. Furthermore, the 21 bridges MEMS switch array had 372°/3.5 mm phase shift operating at 35 GHz. The chip is compacted into a size of 3.5 mm×0.5 mm .