Semi-passive RFID TAGs with double loop antennae arranged as a shifted gate system for stability optimization under delayed electromagnetic interferences

摘要

In this article, we discuss the crucial subject of Semi-passive RFID TAGs system stability. Semi-passive TAGs with double loop antennae arranged as a shifted gate system for stability optimization under delayed electromagnetic interferences. The double loop antenna is employed due to the fact that it consists of two parallel loops — a primary one and secondary one. We define Vi1(t) and Vi2(t) as the voltages on double loop antennae as a function of time. Vi1(t) is the voltage as a function of time time on the primary loop and Vi2(t) is the voltage as a function of time on the secondary loop. The index (i) stands for the first gate (i=1) and second gate (i=2). Due to electromagnetic interference, there are differences in time delays with respect to gate antenna's first and second loop voltages and voltages derivatives. The delayed voltages are Vi1(t−τ1) and Vi2(t−τ2) respectively (τ1 ≠ τ2) and delayed voltages derivatives are dVi1(t−Δ1)/dt, dVi2(t−Δ2)/dt respectively (Δ1 ≠ Δ2; τ1 ≥ 0; τ2 ≥ 0; Δ1, Δ2 ≥ 0).