CPW Tunable Band-Pass Filter Based on RF MEMS Capacitive Shunt and Series Switches

This paper presents a novel tunable band pass filter based on RF MEMS (micro electromechanical systems) capacitive shunt and series switches. Instead of using the traditional method of switching, we are using RF MEMS switches for tuning because of their low insertion loss, low power consumption and high linearity. The tunability of center frequency and bandwidth is achieved by using MEMS based shunt and series switches respectively. The proposed filters are designed on high resistive silicon substrate of 580 µm and 1 µm thicknesses. Both the switches are designed and optimized in terms of material, air gap, beam width, beam thickness to get low pull in voltage, better insertion loss and isolation loss and better tunability. Different Switch parameters are calculated theoretically and are compared with simulated results. Optimized switches are integrated with the CPW structure to get tunability. Of both center frequency and bandwidth. The electromagnetic simulation of the filter has been carried out with the help of HFSS (High frequency structure simulator). By altering the capacitance value in the HFSS model from 36.3 fF to 3.003 Pf, the filter on a 580 μm silicon substrate can be tuned within the frequency range of 0.1 to 0.5 GHz. Within the tuning range, the design filter's insertion loss is between − 2.5 and − 17 decibels. As the capacitance value changes from 0.24 pF to 3.02 Ff, the Bandwidth changes from 0.1 to 2 GHz.