In this work, we propose an efficient finite-difference time-domain (FDTD) simulation technique for the electromagnetic (EM) wave analysis of the Faraday rotation angle in the ionosphere. For this purpose, we first model the physical ionosphere as a scaled-down FDTD computational domain by a space-compression factor. Next, the Faraday rotation angle calculated from the FDTD simulation is calibrated by multiplying the space-compression factor. Numerical examples demonstrate that this novel space-compression-and-cal…