Switchable Magnetless Nonreciprocal Metamaterial (MNM) and its Application to a Switchable Faraday Rotation Metasurface

Recently introduced magnetless nonreciprocal metamaterials (MNMs) may represent a flexible, low-cost and integrated alternative to ferrites for nonreciprocal electromagnetic structures and microwave components. In those MNMs, the direction of gyrotropy is fixed by the fixed unilaterality of the FETs used as loads of the MNM ring particles. This letter makes the MNM's gyrotropy direction switchable, using switchable anti-parallel FET circuit loads. This switchability property is demonstrated experimentally via reversal of the direction of the Faraday angle induced by a switchable MNM metasurface.