RFID TAGs Coil’s dimensional parameters optimization as excitable linear bifurcation systems

Abstract

In this article, very crucial subject discussed in RFID tag's coil design. RFID equivalent circuits of a label can be represent as parallel circuit of capacitance (Cpl), resistance (Rpl), and inductance (Lpc). The label measurement principal is as follow : label positioned in defined distance to measurement coil, low current or voltage source, measuring of IZI and teta of measurement coil, resonance frequency fro at teta = 0, Calculation of unloaded quality factor Q0 out of measured bandwidth BO. The coil design procedure is based on three important steps. The RFID equivalent circuit can be represent as a differential equation which depending on variable parameter. The investigation of RFID's differential equation based on bifurcation theory (Y.A. Kuznetsov), the study of possible changes in the structure of the orbits of a differential equation depending on variable parameters. The article first illustrate certain observations and analyze local bifurcations of an appropriate arbitrary scalar differential equation (J.K. Hale). Since the implicit function theorem is the main ingredient used in these generalizations, include a precise statement of this theorem. Additional analyze the bifurcations of a RFID's differential equation on the circle. Bifurcation behavior of specific differential equations can be encapsulated in certain pictures called bifurcation diagrams. All of that for optimization of RFID tag's dimensional parameters optimization - to get the best performance.