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

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 V_i1(t) and V_i2(t) as the voltages on double loop antennae as a function of time. V_i1(t) is the voltage as a function of time time on the primary loop and V_i2(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 V_i1(t-τ₁) and V_i2(t-τ₂) respectively (τ₁ ≠ τ₂) and delayed voltages derivatives are dV_i1(t-Δ₁)/dt, dV_i2(t-Δ₂)/dt respectively (Δ₁ ≠ Δ₂; τ₁ ≥ 0; τ₂ ≥ 0; Δ₁, Δ₂ ≥ 0).