UNIDIRECTIONAL SURFACE ACOUSTIC WAVE CONVERTER Russian patent published in 1998 - IPC

FIELD: radio electronics; intermediate- and carrier- frequency filters for signal selection in radiotelephones, pagers, mobile communication systems, etc. SUBSTANCE: with electric signal applied to unidirectional converter that has elementary sections of exciting electrodes 2, 3 connected in phase opposition and reflecting electrode 4, surface acoustic waves are excited in piezoelectric sound conductor 1 and propagate in forward and backward directions. Wavelengths of exciting electrodes 2 and 3 in each elementary section having wavelengths b₁ and b₂, respectively, are λ/6 and λ/8, and width b₃ of reflecting electrode 4 equals λ/4; distance between adjacent edges of exciting electrodes 2 and 3 is λ/6 and that between adjacent edges of second exciting and reflecting electrodes 3 and 4 is λ/8, where surface acoustic wave is at intermediate frequency. With mentioned proportions, acoustic wave conversion efficiency is 30% more effective at extremely unidirectional radiation. EFFECT: reduced insertion loss of converter and filter using this converter. 5 dwg