Further improvements of surface transverse wave resonator performance in the 2.0 to 2.5 GHz range

This paper presents state-of-the-art results from improved designs of surface transverse wave (STW) two-port resonators operating in the 2.0 to 2.5 GHz range. With these designs we have succeeded to double both the loaded and unloaded device Q compared to 2.0 GHz devices reported at the 1995 Frequency Control Symposium. Four different designs, fabricated in a conventional photolithographic process, are presented and their electrical performance is discussed. Unloaded device Q values exceeding by 30 to 45% the material Q limit for surface acoustic waves (SAW) and insertion loss values in the 8 to 16 dB range are obtained with 2.0 GHz single and multimode two-port devices. Data on film thickness, finger-to-gap ratio and spacer variation sensitivities as well as temperature stability and radio frequency (RF) power handling are discussed