Coefficients of coupled-mode equations for reversal of directivity transducers on a 50 degrees'Y-25 degrees X La3Ga5SiO14 substrate

Computed results of all the coefficients of coupled-mode equations are pres ented for a transduction center-shift-reversal-of directivity transducer (T CS-RDT) and an electrode-width-controlled-reversal-of-directivity transduce r (EWC-RDT) on a 50 degreesY-25 degreesX La3Ga5-SiO14 substrate. To the bes t of our knowledge, an EWC-RDT is being reported for the first time. The al uminum electrode thickness and width dependences of the coefficients are in vestigated in detail. Numerical results show that we can choose pairs of wi dth and height of the electrodes for a distance of lambda /8 with lambda be ing the surface acoustic wave (SAW) wavelength at the center frequency betw een the reflection center and the transduction one. Our results of the inse rtion loss for a filter composed of a TCS-RDT and two split-electrode inter digital transducers (IDTs) agree well with those of the earlier experiments .