Title :
Intermodulation Read-Out Principle for Passive Wireless Sensors
Author :
Viikari, Ville ; Seppä, Heikki ; Kim, Dong-Wook
Author_Institution :
VTT Tech. Res. Centre, Espoo, Finland
fDate :
4/1/2011 12:00:00 AM
Abstract :
This paper presents a general intermodulation read-out principle for passive wireless sensors. A sensor utilizes a mixing element, such as a varactor, and it can be equipped with a capacitive, inductive, or resistive sensor element. When the sensor is illuminated with signals with two frequencies, it replies the sensor data at an intermodulation frequency. An analytical expression for the intermodulation response of the sensor is derived and verified by simulations. The concept is demonstrated at 1.2 GHz.
Keywords :
capacitive sensors; detector circuits; inductive sensors; intermodulation; mixers (circuits); varactors; capacitive sensor element; frequency 1.2 GHz; inductive sensor element; intermodulation read-out principle; intermodulation response; mixing element; passive wireless sensor; resistive sensor element; varactor; Capacitance; Capacitive sensors; Frequency measurement; RLC circuits; Resonant frequency; Varactors; Mixers; RF identification (RFID); wireless sensors;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2011.2108309
