Capacitive humidity sensors on flexible RFID labels

Capacitive humidity sensors intended to be used with intelligent RFID tags have been produced from polymer foils and/or thin films. They were successfully tested on experimental platforms well reproducing the real operation conditions. Adequate sensing properties (enough sensitivity, good selectivity and linearity and reasonable response and recovery times) have been achieved. The main requirements for a good match to the target applications, that are also fulfilled, are discussed in connection with the readout options and other practical issues.