Microwave Humidity Sensor for Difficult Environmental Conditions

The paper describes an electromagnetic humidity sensor based on a resonance perturbation technique. The sensor is capable of measuring humidity with a wide dynamic range in industrial environment and is insensitive for dust and dirt. The all-metal construction makes the sensor immune to damage by high temperatures. Measurement set-up for a resonance sensor and a construction of a microwave moisture meter are presented. Measurement results with the sensor mounted in a veneer dryer are reported.