Wireless Remote Monitoring of Packaged Passive Sensor for In-situ Pressure Measurement in Highly Reflective Environments

Abstract

This communication reports the design of a packaged passive microwave sensor for measuring applied pressures up to 3bars in highly reflective (metallic) environments. The technological fabrication process is detailed as well as the packaging of the device, which shows an outstanding 440MHz/bar sensitivity between 0.75 and 2.8bars. A microwave Frequency Modulated Continuous Wave (FM-CW) radar is then used for remotely reading the applied pressures. A large full-scale range of 12dB is obtained with a sensitivity of 5.7dB/bar and an estimated precision of ±10mbars between 0.5 and 2bars.

Dual-Polarized Through-Wall Repeater for the Wireless Reading of Millimeter-Wave Passive Sensors

“…The transmission lines between the repeater antennas are short coaxial cables. The pressure sensor is a two-port network (see [2] for details on this sensor). It consists of a silicon membrane and a half-wavelength parallel-edge coupled-line microstrip resonator operating in the radar band and placed inside a cavity.…”

“…Millimeter-wave (mm-wave) Frequency-Modulated Continuous-Wave (FMCW) radar can be advantageously used for the detection and the reading of batteryless (passive), chipless and wireless sensors [1]. From three-dimensional radar imaging techniques, mm-wave FMCW radar allows wirelessly interrogating these sensors, even in highly reflective environments [2]. Mitigation of electromagnetic (EM) clutter in multipath environments can be efficiently achieved from using depolarizing mm-wave passive sensors (see, e.g., [3] for the remote measurement of humidity up to 50 m).…”

Millimetre-Wave Interrogation of Passive Sensors Embedded Inside Closed Reverberant Environments from Dual-Polarized Passive Repeaters

“…The transmission loss in the sensor depends here on the pressure at sensor location. As a matter of fact, the pressure sensor in our present study consists of a silicon membrane and a half-wavelength parallel-edge coupled-line microstrip resonator operating in the radar frequency bandwidth: when the pressure applied on the membrane changes, a deformation of the membrane occurs and modifies the propagation loss (see [3] and Section IV). As a result, the magnitude of the electric field re-radiated by the H-polarized Tx-antenna of the sensor depends on the applied pressure.…”

“…The sensor is a silicon membrane and a half-wavelength parallel-edge coupled-line microstrip resonator [3]. It is manufactured on a 500µm thick borosilicate glass (B33) substrate.…”

“…5(a)). Finally, the microwave transducer is placed inside a 11.25 x 8.3 x 5.56mm 3 Al metallic cavity ( Fig. 5(b)).…”