Title :
Single mode waveguide resonator filters with weak coupling
Author :
Martin, G. ; Wall, B. ; Weihnacht, M.
Abstract :
As known, disturbing transverse modes arising from the waveguide properties of the interdigital transducers and reflectors can appear at SAW resonator filters. Usually, these undesired modes are suppressed by transducer apodization. This method has the disadvantage to increase the transducer impedance. We propose a longitudinally coupled resonator filter, the basic elements of which are able to guide two slowest waveguide modes alone, but to excite and receive the 1st mode only. The basic elements are arranged side by side forming the complete filter permitting coupling with each other weak enough to fulfil the filter specification. The suppression of undesired modes by the construction is demonstrated by transmission measurements
Keywords :
acoustic imaging; acoustic impedance; interdigital transducers; surface acoustic wave couplers; surface acoustic wave resonator filters; 1st mode excitation; 1st mode receiving; SAW resonator filters; complete filter; disturbing transverse modes; filter specification; interdigital reflectors; interdigital transducers; longitudinally coupled resonator filter; single mode waveguide resonator filters; slowest waveguide mode guiding; transducer apodization; transducer impedance; transmission measurements; undesired mode suppression; undesired modes; waveguide properties; weak coupling; Acoustic imaging/mapping; Interdigital transducers; Surface acoustic wave couplers; Surface acoustic wave resonator filters;
Conference_Titel :
Ultrasonics Symposium, 1994. Proceedings., 1994 IEEE
Print_ISBN :
0-7803-2012-3
DOI :
10.1109/ULTSYM.1994.401564
