Patent ID: 8318099

Claim:
A detection system utilizing at least one radiofrequency identification (RFID) tag, comprising: an RFID tag comprising; a substrate; an antenna is disposed on said substrate; a sensor material disposed adjacent to at least a portion of the antenna and the sensor material being selected to be sensitive to one of chemical or biological environment; and a reader for receiving and processing signals from said RFID tag, wherein said reader is configured to measure a signal in the form of a complex impedance from said RFID tag wherein said signal comprises a plurality of frequency shifts and changes in magnitude of the and imaginary parts of the complex impedance to provide position independent responses from said RFID tag; wherein said frequency shifts comprise a frequency shift of the maximum of the imaginary part of the complex impedance (F1 shift), a frequency shift of the minimum of the imaginary part of the complex impedance (F2 shift), a frequency shift of the maximum part of the complex impedance (Fp), and changes in magnitude of the real part of the complex impedance (Zp); and, wherein said complex impedance related to a nature and a concentration of analyte species is derived from multivariate analysis.