The characterization of a wireless passive temperature and humidity sensor was conducted inside an environmental chamber.
The humidity of the chamber was changed from 55%RH to 95%RH and the temperature was changed from 10 °C to 40 °C.
The deviation of the temperature and the humidity during measurement was ± 0.5 °C and ± 3%RH, respectively.
The small sensing range of temperature and humidity was limited by the properties of GO films.
The properties of the Go films would be influenced by synthesized method, dispersion concentrations or synthesized condition, etc
The schematic for the passive telemetry measurement is shown in Fig. 7.
The system consists of a telemetric unit and a wireless transducer unit.
An antenna analyzer connected with a readout coil was used as the telemetric unit to measure the passive wireless sensor.
The temperature of the chamber was controlled to maintained constant range from 10 to 40 °C at 5 °C intervals.
At each temperature point, the humidity was controlled from 50% RH to 95% RH at 2% intervals.
The coupling coefficient k plays a role in the multiple parameters measurement procedure
During the whole measurement procedure, locations of the readout coil and the LC sensor were precisely controlled for consistent coupling factor.
And the coupling factor k in the whole measurement was 0.125 as shown in Table I.