The results of numerical and experimental analysis of the parameters of a singlefrequency micro wave thinfilm electroacoustic resonator based on an (0001)AlN piezofilm with an acoustic reflector operat ing at a frequency of 10 GHz are presented. The effect of the reflector design on the resonator characteristics is considered. Using the modified Butterworth–Van Dyke model, it was shown that the ohmic resistance of electrodes and entrance paths substantially decreases the Qfactor at the resonance frequency of series and the acoustic losses in the resonator deteriorate the Qfactor at the parallel resonance frequency