SELF-MATCHING DIGITAL SURFACE ACOUSTIC WAVE FILTER Russian patent published in 1997 - IPC

FIELD: radio engineering, in particular, devices for frequency selection of radio signals. SUBSTANCE: device has piezoelectric waveguide, input and output opposing-rod converters which have identical electrodes which are located on working surface in parallel acoustic channels. Their centers are shifted by l=n·λ₀/ 6, where λ₀ is length of surface acoustic wave for central frequency of filter, n is odd integer. In addition device has two reflecting multiple-strip couplers, which have third or four strip electrodes for period of their structure. Strip electrodes are located on surface of waveguide on both sides of input and output opposing rod converters so that apertures of both acoustic channels are covered. Periods of electrodes of opposing rod converters and reflecting multiple-strip couplers, number of pairs of electrodes of both opposing rod converters conforms to conditions that provide lesser losses in self-matching mode due to decreased length of electrodes of both converters and reflecting multiple-strip couplers. EFFECT: decreased losses. 11 dwg