Relative Damping of Parallel Antennas for Sensing and Tuning

Radio Frequency Identification (RFID) tags having functionalized carbon nanotubes (CNTs) engineered to change in resistance when exposed to a variety of analytes to provide an inexpensive framework for distributed sensing. For example, a printing process can be developed for liquid inks comprising CNTs, and RFID sensors can be fabricated with functionalized CNTs as the active elements. The tags can work independent of distance and can sense changes in resistance of a sensing element. The tags can include an antenna with an inductive loop and two sets of dipole arms having functionalized carbon nanotubes, and a RFID chip that separates the two sets of dipole arms. The dipole arms can capture an analyte on a plurality of sensors and generate a plurality of resonant peaks therefrom. The peaks can be analyzed by comparing the damping therebetween, or by shifting the resonant frequency of the tag to determine presence of the analyte.