HIGH-FREQUENCY UNIDIRECTIONAL CONVERTER OF SURFACE ACOUSTIC WAVES Russian patent published in 2001 - IPC

FIELD: radio electronics. SUBSTANCE: invention can find use in filters of intermediate and carrier radio frequencies for selection of signals in radio telephones, pagers, mobile communication systems, etc. Surface acoustic waves propagating in forward and backward directions are excited in piezoelectric substrate with supply of electric signal to unidirectional converter composed of elementary sections of three antiphase exciting electrodes and one reflecting electrode. Certain conditions are fulfilled in unidirectional converter to ensure predominant direction of radiation of surface acoustic waves along axis X. Widths of first, second and third exciting electrodes in each elementary section are chosen from given relations. In this case reflecting electrode is connected to potential or " ground summing bus and polarity of connection of reflecting electrode with above-mentioned buses is chosen opposite to polarity of connection of third exciting electrode to same buses. Adjacent elementary sections are arranged with specified interval and polarity of connection of adjacent elementary sections to potential or " ground " summing bus alternates. EFFECT: reduction of introduced losses. 3 cl, 4 dwg