Characterization of Ferromagnetic Resonance Identification (Fmr-Id) Tag in Semi-Wireless Configuration

This work characterizes a ferromagnetic resonance identification (FMR-ID) tag with magnetic nanowires (MNWs) in an anodized aluminum oxide (AAO) template using a semiwireless configuration. The MNWs exhibit distinct ferromagnetic resonance (FMR) frequencies under DC magnetic field variation. A benchmark test using an electromagnet (Emag) to generate a controlled low DC field and vector network analyzer (VNA) operating from 15-30 GHz, produced 5-bit data. To demonstrate portability, Emag is replaced with Disc-shaped permanent magnets (Pmag) that also validate a 5-bit data response. A semiwireless detection setup (a horn antenna and a metamaterial patch antenna (MMPA)) with lower bandwidth successfully retrieved 2bits of the data. Pmag and Emag FMR responses have similar slopes to the Kittel equation with an offset of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 1 \text{GHz}$</tex>, believed to be due to DC field differences. These predictable responses demonstrate the feasibility of a semi-wireless FMR-ID system for use in enhanced RFID security applications.