A 24GHz environmental sensor based on the modulated scattering technique (MST)

This work presents the design of an environmental sensor based on the modulated scattering technique (MST). The sensor works in the K band at 24 GHz and achieves an operative range of about 5 meters with a limited amount of power. The communication between the reader and the sensor is obtained using the same standard EM4102 RFID protocol, and the information is carried on by modulating the load of the tag antenna with a suitable switch circuit based on a mosfet switch. The antenna sensor, the rectifying circuit and the switch have been optimized to reach the maximum operative range. A sensor prototype has been designed, fabricated and experimentally assessed. The obtained experimental results are quite promising.