Automatic Measurement Technique of Electromagnetic Rotation in a Nonreciprocal Medium

Faraday rotation is a nonreciprocal rotation of wave polarization as a wave propagates. Faraday rotation is a critical property in a wide range of applications, from wireless communication to quantum memory, from bio-magnetic field detection to sensor applications. Characterizing the nonreciprocal polarization rotation accurately is very important for these applications. This article aims at developing a simple, automated test bench procedure based on simplified mathematical modeling to measure polarization rotation of an electromagnetic (EM) wave upon propagation through a nonreciprocal medium. A comprehensive measurement approach is developed from the scattering matrix. The proposed measurement procedure is demonstrated using an electronically tunable nonreciprocal metamaterial, and the accuracy of the proposed method is verified by comparison to the well-accepted conventional measurement technique, as well as 3-D EM simulation.