Wireless sensing of open loop micro coils using an air core helical coil

In this paper we report here remote sensing of open loop micro coil parameters using an air core helical coil. Test micro coil is inductive coupled in the near electromagnetic field by placing it inside the air core helical coil and measuring the wirelessly reflected impedance signal. The coupled system is analytically modeled including the effects of the frequency depended coupling capacitances between the helical coil and the open loop test micro coil. Non linear least square estimation is used to extract the best estimated parameter values of the open loop test micro coil. FEM simulations are performed in COMSOL Multiphyscics and HFSS (High Frequency structure Simulation) to visualize the magnetic field behavior and to verify the wirelessly measured results.