An Oscillator with Inductively Coupled Resonators for Readout of Stretchable Resistive Strain Sensor

This paper proposes a wireless and stretchable sensor which uses an oscillator with an inductively coupled resonator. By delving into the malleable nature of these cutting-edge electronics, we determine the most effective circuit parameters to optimize signal behavior for specific applications. The findings showed that the simulated frequency shift sensitivity to variations in sensor resistance in a simple NIC based oscillator circuit could be accurately modeled. The simulation was then confirmed by measurement with a reader circuit inductively coupled to a stretchable sensor. Further resistive strain experiments revealed a frequency shift of 132 Hz per 1% of strain in the sensor resistor, which is potentially high enough to measure and detect any physical phenomena that can induce strain on a human body, even down to the extremely small artery deformations caused by a pulse wave from the heart.