Enhancing the transparency of gyrotropic magnet-less non-reciprocal metamaterials (MNMs) using slot pair particles

An annular slot pair particle loaded by a transistor is introduced to enhance the transparency of gyrotropic magnet-less non-reciprocal metamaterial (MNMs). Previously reported MNMs support only one gyrotropic mode, and therefore suffer from partial opacity because at least two gyrotropic modes are required to cancel out reflection in the presence of gyrotropy. The proposed MNM particle supports two gyrotropic modes: a dark mode and a bright mode. As a result, it provides the first reflection-less gyrotropic MNM. First, it is shown that the conducting ring pair particle MNM supports two modes but that only one of them is gyrotropic, which induces reflection. Next, it is shown that the single annular slot particle support only one gyrotropic mode, which leads to the same issue. Finally, the annular slot pair particle MNM is introduced and shown by full-wave simulation to support two gyrotropic modes.