Title :
Low-loss SAW filters using new SPUDT structures
Author :
Chvets, V.B. ; Ivanov, P.G. ; Makarov, V.M. ; Orlov, V.S.
Author_Institution :
Radiocommun. Res. Inst., Moscow, Russia
Abstract :
The new SPUDT structures based on triple electrode sections (TES) per wavelength with the period between SAW sources about nλ/3 are presented. The simulation technique which accounts for second order effects has been developed within the framework of modified equivalent circuit model. The SPUDT structures have been implemented in filters with 0.1-3.2% bandwidths fabricated on quartz and LiTaO3 substrates. The results of simulation have been verified experimentally and show that insertion loss of TES SPUDT filters is less by 1.0-1.5 dB than that in conventional SPUDT filters. The impedance frequency dependence becomes more symmetrical and the passband distortions are reduced. Stopband rejection is 50-60 dB
Keywords :
acoustic impedance; equivalent circuits; lithium compounds; losses; quartz; surface acoustic wave filters; surface acoustic wave resonator filters; surface acoustic wave transducers; LiTaO3; SPUDT structures; SiO2; TES SPUDT filters; bandwidths; impedance frequency dependence; insertion loss; low-loss SAW filters; modified equivalent circuit model; passband distortions; quartz; second order effects; simulation technique; stopband rejection; triple electrode sections; Band pass filters; Bandwidth; Circuit simulation; Electrodes; Equivalent circuits; Frequency dependence; Impedance; Insertion loss; SAW filters; Surface acoustic waves;
Conference_Titel :
Ultrasonics Symposium, 1997. Proceedings., 1997 IEEE
Conference_Location :
Toronto, Ont.
Print_ISBN :
0-7803-4153-8
DOI :
10.1109/ULTSYM.1997.662982
