Wide piezoelectric tuning of ltcc bandpass filters

The increasing number of frequency bands and services in wireless communications is causing a demand for analogue active and passive frontend components with wide bandwidth or tuning range, respectively. Similar to microelectromechanical systems (MEMS), this work presents a parallel plate capacitor with multilayer dielectrics and piezoelectrically movable top electrode as an advantageous tunable element with no addition of any lossy material. When applied as a shunt capacitor in a coupled microstrip-line LTCC bandpass filter, the center frequency of the filter is tuned from 1.1 GHz to 2.6 GHz with 200 V control voltage and low insertion loss of 2 to 4 dB. The analysis of the device by full-wave simulation reveals a potential tuning range from 0.8 GHz to 2.8 GHz when the thin-film processability of the LTCC surface is properly controlled. Index Terms— Bonding, ceramics, pi