An acoustic‐surface‐wave resonator using a single periodic grating is described. A 633‐line grating was obtained by ion implantation in quartz (Y,X) with a reflection coefficient larger than 99% at about 125 MHz. An interdigital transducer deposited in the middle of this grating was found to have an input impedance that depended upon the acoustic characteristics of the array. A peak impedance was obtained as a result of the buildup of resonance in the grating and was used to stabilize the frequency of the conventional L‐C oscillator. In this case, the temperature stability of the oscillator is equal to that of the quartz substrate, that is, 22×10−6/deg.