Embedded chipless RFID measurement methodology for microwave materials characterization

The use of chipless RFID is rapidly growing with applications for both identification and sensing purposes. In existing chipless RFID technology for identification purposes, radar cross-section (RCS) vs. frequency information is often used to create a unique identification (binary) code of 1's and 0's. In contrast, for purposes such as environmental sensing (i.e., temperature, humidity, gas concentration, etc.), a shift in the RCS frequency response is then correlated to the sought-for information. In this paper the utility of embedding chipless RFID sensors in various dielectric materials is investigated, where changes in the material properties cause a shift in the RFID frequency response and the changes are translated to a change in its original binary code. To illustrate the efficacy of this unique technique for materials characterization, electromagnetic simulations and measurements were conducted, the result of which are presented in this paper.