Title :
ZnO based thin film bulk acoustic wave filters for EGSM band
Author :
Kaitila, J. ; Ylilammi, M. ; Molarius, J. ; Ellä, J. ; Makkonen, T.
Author_Institution :
Microelectron. Centre, VTT Electron., Finland
Abstract :
We present results for a ZnO based filters for the mobile Extended GSM (EGSM) Rx band centered at 942.5 MHz. Our devices are of the SMR type. The acoustical isolation from the glass substrate is achieved by a tungsten-silicon dioxide quarter wavelength mirror. Resonators with an effective coupling coefficient of 0.236 and Q~800 have been achieved. The filters are realized as either 3-section ladder or 2-section lattice connected FBARs without any external components. The ladder filters achieve a 3.5 dB absolute bandwidth of 39 MHz with minimum insertion loss of 1.3 dB, stop band rejection at 23 dB and VSWR of 2.2 in the pass band. The balanced filter design has a slightly larger bandwidth of 46 MHz and improved stop band behavior characteristic for this type of device
Keywords :
Q-factor; acoustic resonator filters; bulk acoustic wave devices; cellular radio; ladder filters; piezoelectric thin films; zinc compounds; 1.3 dB; 39 MHz; 46 MHz; 942.5 MHz; FBAR technology; Q-factor; W-SiO2; ZnO; ZnO thin film bulk acoustic wave filter; acoustical isolation; coupling coefficient; glass substrate; ladder filter; mobile EGSM Rx band; solidly mounted resonator; tungsten-silicon dioxide quarter wavelength mirror; Acoustic waves; Band pass filters; Bandwidth; GSM; Glass; Mirrors; Resonator filters; Substrates; Transistors; Zinc oxide;
Conference_Titel :
Ultrasonics Symposium, 2001 IEEE
Conference_Location :
Atlanta, GA
Print_ISBN :
0-7803-7177-1
DOI :
10.1109/ULTSYM.2001.991844
