Impact of receiver coil misalignment on near-field communication system performance

The coupling coefficient is not only affected by the distance between the coils but also by the misalignment of the coils. In this paper, a simple intuitive expression of coupling coefficient for laterally and angularly misaligned coils is derived, based on the near-field expressions for a small loop antenna, and special cases of perfectly aligned coils, axially placed angularly misaligned coils, laterally displaced coils, co-planar laterally displaced coils are discussed. These simple cases offer an insight into impact of receiver coil misalignment on the near-field communication system performance.