Equivalent circuit of a composite acoustic resonator for microwave radioelectronic devices

On the basis of analyzing the expression for the input electric impedance of a composite microwave acoustic resonator, its equivalent electric circuit is constructed. It is shown that, for high-order harmonics, the difference between the antiresonance and resonance frequencies is determined not only by the electromechanical coupling coefficient, but also by the loss in the structure. The conditions under which this difference corresponds to the bandwidth of the equivalent parallel electric oscillatory circuit are formulated. Expressions for the resonance and antiresonance frequencies are derived. The procedures of determining the Q factor and the electromechanical coupling coefficient from the measured resonance and antiresonance frequencies of the structure are justified.