Significance of non-spiral planar microcoils over spiral coils for biomedical applications: Design, simulation and comparison with spiral coil

Non-spiral planar microcoil presented in this paper has a different structure and fabrication easiness compared to conventional planar spiral coils. Non spiral coils are suitable in biomedical applications for low field magnetic resonance measurements. Non-spiral coil does not require interconnection between inner coil and output pads. Therefore its fabrication requires only one metal level without interconnection whereas conventional spiral type requires at least two metal layers. Comparison between spiral and non-spiral coils is presented here. Although spiral coil has more flux density than that of non-spiral coil, non-spiral coil has an interesting property of increased flux density at the innermost turn with reduced number of turns. Simulation of coil types is performed using COMSOL Multiphysics software.