Title :
SAW unidirectional interdigital transducer with ultra-low insertion loss and wide band in 10MHZ-10GHZ range
Author :
Satoh, Yusuke ; Yamanouchi, Kazuhiko
Author_Institution :
Tohoku Inst. of Technol., Sendai, Japan
Abstract :
Surface acoustic wave (SAW) filters employing unidirectional interdigital transducers (UDT) show low loss properties. We proposed a single phase unidirectional transducer (UDT) with about λ/4 electrode width of the best transducer efficiency. The UDTs are obtained by IDT on the very thin dielectric grating with λ/8 shifts. The electromechanical couplings (k2) of electrodes on SiO2 films decrease rapidly for film thickness. Therefore the good properties of UDT are obtained for the very thin thickness of SiO2 grating (about 0.03μm at 2GHz with electrode thickness of Al of 0.07μm). In this paper we describe the experimental results of wide band and very low loss filters with below 1dB insertion loss at 500MHz and 2GHz-range.
Keywords :
IV-VI semiconductors; UHF filters; VHF filters; interdigital transducers; microwave filters; silicon compounds; surface acoustic wave filters; 0.01 to 10 GHz; 0.03 micron; 0.07 micron; SAW filter; SiO2; electromechanical couplings; insertion loss; low loss filter; surface acoustic wave; thin dielectric grating; unidirectional interdigital transducers; Acoustic transducers; Acoustic waves; Band pass filters; Dielectrics; Electrodes; Gratings; Insertion loss; Reflection; Surface acoustic waves; Ultra wideband technology;
Conference_Titel :
Frequency Control Symposium and Exposition, 2005. Proceedings of the 2005 IEEE International
Print_ISBN :
0-7803-9053-9
DOI :
10.1109/FREQ.2005.1573997
