Operation of a SAW reflection grating at harmonic frequencies

Abstract

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 /spl eta/. These concepts are applied to an experimental study of a one-port LSAW resonator on 64/spl deg/ LiNbO/sub 3/ incorporating a three-finger per period IDT finger structure, and operating at both the fundamental (489 MHz) and the second harmonic (1010 MHz).