Unidirectional Loop Metamaterials (ULM) as Magnetless Artificial Ferrimagnetic Materials: Principles and Applications

This letter presents an overview of unidirectional loop metamaterial (ULM) structures and applications. Mimicking electron spin precession in ferrites using loops with unidirectional loads (typically transistors), the ULM exhibits all the fundamental properties of ferrite materials and represents the
only existing magnetless ferrimagnetic medium
. We present here an extended explanation of ULM physics and unified description of its component and system applications.