Wireless Measurement of the Pressure from the Ka-Band Radar Echo of a 3D-Printed Microfluidic Depolarizing Sensor

In this paper, we report the remote measurement of the pressure from the Radar interrogation of a novel microfluidic passive sensor. This sensor includes a microfluidic band-pass filter, whose transmission coefficient in the Ka-band depends on the applied pressure, and two cross-polarized Rx- and Tx-antennas connected to the terminals of the filter for enhancing the full-scale measurement range of the sensor's Radar echo level. The filter is 3D-printed via the Sintering Laser Melting technique. For a Radar-to-sensor distance of 3 meters, a high full-scale measurement range of 8dB on the echo level is reported with a measurement sensitivity of 0,03dB/mbar for applied pressure ranging from 350 mbar to 640 mbar.