A printed wireless fluidic pressure sensor

Abstract

An inkjet-printed inductor–capacitor (LC) resonator is demonstrated for wireless monitoring of pressure in aqueous environments. The sensing mechanism is based on a compressible capacitor that modulates the LC circuit resonant frequency depending on the applied pressure. The trace conductivity and geometric designs of inductors are improved to increase mutual inductive coupling between the sensor and the readout coil. The dielectric porosity in the capacitive sensors are tuned to enhance pressure sensitivity. The encapsulated sensor showed a linear response to pressure between 30 and 170 mmHg (4–23 kPa) with respect to atmospheric pressure and a resolution of 3 mmHg. The sensor temporal response is up to 6 Hz and capable of capturing typical heart-pulse waveforms as a proof-of-concept demonstration.