Dielectric material determination using the radar equation in RFID sensor applications

A radar-cross section (RCS) of passive printed tags in a radio frequency identification (RFID) is presented to determine a dielectric constant of a material under test (MUT). In this paper, a printed loop tag with a meander-line is employed as an RFID sensor. The optimum parameters of the proposed RFID sensor are obtained using the CST Microwave Studio program. This paper employs two RFID sensors with different RCS to improve the accuracy of dielectric material determination. The relation between the read range (Rmax) and the real part of dielectric constant (έr) can be used to determine the dielectric constant of MUT.