Excitation of acoustic surface waves with a grating-coupled gunn oscillator

Up to 0.25 mW of acoustic surface wave power at 225 MHz have been generated on LiNbO3 with a Gunn oscillator via periodic piezoelectric coupling of the Gunn domain electric fields across an air gap. The coupling periodicity is produced by a metal or dielectric grating on the LiNbO3 surface. The ratio of generated surface wave power Pac to the electrical pulse power is up to 2.5×10-6 for the metal grating and 10 -7 for the dielectric grating. The observed dependence of P ac on the number of grating fingers is explained by the degree of phase matching between Gunn domains and acoustic surface waves. © 1971 The American Institute of Physics.