Patent attributes
A transponder is provided. The transponder includes an antenna, a modulation/demodulation unit (diode) that modulates and demodulates signals received and transmitted from and to a controller, a pressure resonator including a first piezoelectric single-crystal resonating element and a pressure sensor, and a reference resonator including a second piezoelectric single-crystal resonating element and a capacitor. The controller transmits a signal for resonating the pressure resonator and the reference resonator, receives a signal having the resonance frequency of the pressure resonator and a signal having the resonance frequency of the reference resonator, and computes a measured value in accordance with the resonance frequencies of the two resonators retrieved from the received signals.