Methods and apparatus for twisting rectangular rotor and stator conductor ends whereby most if not all conductor ends are bent at once, radially adjacent ends being bent in opposite directions. Each of the resonators has a piezoelectric thin film having piezoelectric characteristic, and lower and upper electrodes disposed on opposite surfaces of the piezoelectric thin film for applying an excitation voltage to the piezoelectric thin film. The processing unit includes a mechanism to measure voltage at terminals of the second oscillating circuit and a controller that can be used to vary resonance frequency of the first oscillating circuit as a function of the value of the measured voltage to optimize frequency tuning between the extender and the readwrite station.