the invention concerns a novel bulk acoustic wave resonator design and method of manufacturing thereof the bulk acoustic wave resonator comprises a resonator portion , which is provided with at least one void having the form of a trench which forms a continuous closed path on the resonator portion . by manufacturing the void in the same processing step as the outer dimensions of the resonator portion , the effect of processing variations on the resonant frequency of the resonator can be reduced . by means of the invention , the accuracy of baw resonators can be increased .