Title :
Low loss and high rejection RF SAW filter using improved design techniques
Author :
Fujita, Yuji ; Shiba, Takashi ; Kondo, Seima ; Matsuura, Naoki ; Hikita, Masayuki ; Ogawa, Seiichi
Author_Institution :
Hitachi Media Electron. Co. Ltd., Yokohama, Japan
Abstract :
A new high-performance surface acoustic wave (SAW) filter for cordless phone is presented in this paper. The transition characteristics are strongly dependent on a transducer structure and a film thickness owing to the effects of the bulk wave and the electro-mechanical coupling. Similarly the sidelobe characteristics depend on a wire-bonding and an electrode patterning because of the electromagnetic feed through effect. We have simulated and designed with consideration of the bulk wave and the feed through effects using the improved equivalent circuit model. Consequently we have developed a 3 mm square SMD SAW filter with 2.4 dB loss, 5.4 MHz transition bandwidth and over 65 dB sidelobe rejection for 900 MHz ISM band cordless phone systems. The experimental results are in good agreement with the simulations
Keywords :
cordless telephone systems; equivalent circuits; radiofrequency filters; surface acoustic wave filters; 2.4 dB; 3 mm; 5.4 MHz; 900 MHz; ISM band cordless phone system; RF SAW filter; SMD surface acoustic wave filter; bulk wave; design; electrode patterning; electromagnetic feedthrough; electromechanical coupling; equivalent circuit model; film thickness; loss; numerical simulation; sidelobe rejection; transducer; transition bandwidth; wire bonding; Acoustic transducers; Acoustic waves; Circuit simulation; Coupling circuits; Electrodes; Equivalent circuits; Feeds; Radio frequency; SAW filters; Surface acoustic waves;
Conference_Titel :
Ultrasonics Symposium, 1998. Proceedings., 1998 IEEE
Conference_Location :
Sendai
Print_ISBN :
0-7803-4095-7
DOI :
10.1109/ULTSYM.1998.762173
