Title :
GHz-range low-loss wide band filter using new floating electrode type unidirectional transducers
Author :
Yamanouchi, Kazuhiko ; Lee, CH S. ; Yamamoto, K. ; Meguro, T. ; Odagawa, H.
Author_Institution :
Res. Inst. of Electr. Commun., Tohoku Univ., Sendai, Japan
Abstract :
K. Yamanouchi et al. (1991) reported a very low loss surface acoustic wave (SAW) filter with minimum insertion loss of 1.9 dB at 1.0 GHz using a floating electrode type unidirectional transducer (FEUDT). The dependence of directivity on the electrode thickness for the λ/10 type FEUDT is investigated here. Experimental results show minimum insertion loss of 6.2 dB at 4.1 GHz and 2.5 dB at 2.0 GHz. The dependence of directivity on the electrode thickness at 4 GHz differs from that at 2 GHz. The resistivities of various Al films were measured, and their surfaces are observed by scanning tunneling microscopy. An increase of the resistance due to pinholes which appear after heating is noted
Keywords :
acoustic microwave devices; electrodes; losses; microwave filters; surface acoustic wave filters; ultrasonic transducers; 2 GHz; 2.5 dB; 4.1 GHz; 6.2 dB; Al film resistivity; FEUDT; LiNbO3 substrate; SAW filter; directivity; electrode thickness; floating electrode type unidirectional transducers; low-loss wide band filter; minimum insertion loss; pinholes; scanning tunneling microscopy; Acoustic transducers; Acoustic waves; Conductivity; Electrical resistance measurement; Electrodes; Filters; Insertion loss; Surface acoustic waves; Surface resistance; Wideband;
Conference_Titel :
Ultrasonics Symposium, 1992. Proceedings., IEEE 1992
Conference_Location :
Tucson, AZ
Print_ISBN :
0-7803-0562-0
DOI :
10.1109/ULTSYM.1992.276049
