U.S. Philips Corporation

Frederick Warren Smith

Richard F Mitchell

Martin Redwood

David E Penna

David W Parker

Richard Stevens

John S Palfreeman

An acoustic wave resonator device includes two pairs of coupled spaced apart reflectors which define two resonant cavities. The two cavities are each provided with two interdigital transducers which provide intercavity coupling. Additional reactance coupling between the transducers in one cavity combines with the equivalent cavity reactance to provide series or parallel resonance at a selected pole frequency.

Acoustic wave devices

A surface acoustic wave band-pass filter comprising a piezoelectric substrate having on one surface first and second SAW resonators tuned to the same frequency and coupled together. An input transducer is coupled to the first resonator and an output transducer is coupled to the second resonator. Each resonator is preferably formed by two spaced apart aligned grating reflectors and the two resonators are preferably coupled by an array of discrete parallel metallic strips extending between the two cavity resonators.

Electrical filters including coupled resonators

A length weighted interdigital transducer has .lambda./2 spaced electrodes within the overlap region. Outside the overlap region, the overlapping .lambda./2 spaced electrodes are connected to the bus bars by pairs of .lambda./4 spaced electrodes and extra 'dummy' pairs of .lambda./4 spaced electrodes are also connected to the bus bars. The .lambda./2 spaced electrodes give a good manufacturing yield, and the .lambda./4 spaced pairs of electrodes and pairs of dummy electrodes provide compensation for wavefront distortion combined with low 'interactions.'

Growing community of inventors

Sutton, United Kingdom

Frederick Warren Smith