The present disclosure relates to nanoresonator oscillators or NEMS (nanoelectromechanical system) oscillators. A circuit for measuring the oscillation frequency of a resonator is provided, comprising a first phase-locked feedback loop locking the frequency of a controlled oscillator at the resonant frequency of the resonator, this first loop comprising a first phase comparator. Furthermore, a second feedback loop is provided which searches for and stores the loop phase shift introduced by the resonator and its amplification circuit when they are locked at resonance by the first loop. The first and the second loops operate during a calibration phase. A third self-oscillation loop is set up during an operation phase. It directly links the output of the controllable phase shifter to the input of the resonator. The phase shifter receives the phase-shift control stored by the second loop.

The present invention relates to a resonant frequency tunable antenna, and may provide a resonant frequency tunable antenna which comprises: a first ground part; a power supply part connected in the longitudinal direction of the antenna from the first power supply part; and a second ground part connected in the longitudinal direction of the antenna from the power supply part, wherein the second ground part is a variable ground part, the second ground part and the power supply part are connected by a switch, and the switch is connected to a common terminal which is grounded, so that the second ground part and the power supply part are linked and controlled.