A novel tunable low-pass filter based on MEMS and CPW

This paper presents a new type of tunable low-pass filter for millimeter-waves. The filter is based on the slow-wave coplanar waveguide (CPW) lines and tuned by the MEMS capacitive shunt switches. There are 5 switches which can provide two orders of tunable mode. In the first order tuning, the 3 dB cut-off frequency changes from 8.2 GHz to 10.5 GHz, and the second order tuning is 8.2 GHz to 16.8 GHz. The tested results show that the pass-band ripple is less than 2 dB and the maximal out-of-band rejection is better than 20 dB. The driven voltages of the switches are around 40 V.