Title :
Matching of single-phase unidirectional SAW transducers and a demonstration using a low-loss EWC/SPUDT filter
Author :
Abbott, B.P. ; Hartmann, C.S. ; Malocha, D.C.
Author_Institution :
Dept. of Electr. Eng., Univ. of Central Florida, Orlando, FL, USA
Abstract :
The authors present the theoretical criterion for calculating the electrical port load required for matching a SPUDT (single-phase unidirectional transducer) and an efficient procedure for tuning a SPUDT filter. The theoretical development identifies a potentially useful class of SPUDTs that requires no matching network to achieve a high degree of triple transit cancellation. The sensitivity of the SPUDT filter´s insertion loss to parasitic resistance is explained. It is found that the insertion loss of a SPUDT can increase as the thickness of the metallic overlay is increased (contrary to conventional surface acoustic wave technologies). The process of matching a SPUDT filter is demonstrated using a 196 MHz filter packaged in an 18-pin DIP package and matched with miniature internal coils. A triple transit suppression of 55 dB was obtained for an insertion loss of 8.6 dB
Keywords :
frequency response; matched filters; piezoelectric transducers; surface acoustic wave filters; transient response; ultrasonic transducers; 196 MHz; 8.6 dB; DIP package; EWC/SPUDT filter; SAW SPUDT filter; electrical port load; electrode width controlled structure; frequency response; impulse response; insertion loss; matching; metallic overlay thickness; miniature internal coils; parasitic resistance; single-phase unidirectional SAW transducers; single-phase unidirectional transducer; triple transit cancellation; Acoustic distortion; Acoustic reflection; Acoustic transducers; Admittance; Insertion loss; Laboratories; Matched filters; Packaging; Solid state circuits; Surface acoustic waves;
Conference_Titel :
Ultrasonics Symposium, 1990. Proceedings., IEEE 1990
Conference_Location :
Honolulu, HI
DOI :
10.1109/ULTSYM.1990.171325
