Operation of a SAW reflection grating at harmonic frequencies

Operation at harmonic frequencies of both IDTs and reflection gratings represents one possible technique for circumventing fabrication, tolerance and power dissipation limitations in SAW/LSAW resonators and resonator-filters, as mobile and wireless frequencies extend well above 2 GHz. Here, characteristic matrices [M] for optical interference gratings are applied to SAW reflection gratings operating at fundamental and harmonic frequencies. Both even and odd harmonic responses of high reflectivity can be obtained, to a level dependent on both energy storage and metallization ratio η. These concepts are applied to an experimental study of a one-port LSAW resonator on 64° LiNbO₃ incorporating a three-finger per period IDT finger structure, and operating at both the fundamental (489 MHz) and the second harmonic (1010 MHz)