Title :
Low loss filters using group-type SPUDT transducers
Author :
Morgan, D.P. ; Durrant, P.
Abstract :
The group-type SPUDT (single-phase unidirectional transducer) offers low loss and good triple-transit suppression in a single-metallization device, with considerable flexibility in the designs of transducers and gratings. It is shown that many center-frequency properties of a weighted SPUDT, including directivity and conversion loss, are given by simple expressions dependent only on the grating properties. A reflective array model is used to analyze transducers and gratings, with the results cascaded to give the SPUDT performance. Results are shown for a withdrawal-weighted SPUDT design with a conversion loss of 0.24 dB and 22-dB stopband rejection. It is concluded that electrode interactions are tolerable, allowing high-frequency (1 GHz) operation, and that bandwidths up to 5% should be feasible
Keywords :
piezoelectric transducers; surface acoustic wave filters; ultrasonic transducers; 0.24 dB; 1 GHz; HF operation; bandwidths; center-frequency properties; conversion loss; directivity; electrode interactions; grating properties; group-type SPUDT transducers; low loss SAW filters; reflective array model; single-metallization device; single-phase unidirectional transducer; stopband rejection; triple-transit suppression; withdrawal-weighted SPUDT design; Bandwidth; Electrodes; Filters; Frequency; Gratings; Microelectronics; Performance analysis; Reflection; Surface acoustic waves; Transducers;
Conference_Titel :
Ultrasonics Symposium, 1990. Proceedings., IEEE 1990
Conference_Location :
Honolulu, HI
DOI :
10.1109/ULTSYM.1990.171322
