This disclosure provides implementations of electromechanical systems piezoelectric resonator transformers, devices, apparatus, systems, and related processes. In one aspect, a transformer includes a piezoelectric layer; a first conductive layer arranged over a first surface of the piezoelectric layer including a first set of electrodes and a second set of electrodes interdigitated with the first set. The transformer includes a second conductive layer arranged over a second surface including at least a third set of electrodes. In some implementations, the transformer includes a first port capable of receiving an input signal and to which the first set of electrodes are coupled, and a second port capable of being coupled to a load and of outputting an output signal, the second set of electrodes being coupled to the second port. Generally, a ratio of the number of electrodes of the second set to the first set characterizes a transformation ratio.