Reciprocity is a fundamental principle in optics, requiring that the response of a transmission
channel is symmetric when source and observation points are interchanged. It is of major …

In this article, we provide a comprehensive review of past and present efforts in the field of
microwave nonreciprocity with an emphasis on the most commonly used nonreciprocal …

This tutorial provides an intuitive and concrete description of the phenomena of
electromagnetic nonreciprocity that will be useful for readers with engineering or physics …

Floquet topological insulators, which have an exotic topological order sustained by time-
varying Hamiltonians, could be of use in a range of technologies, including wireless …

Time has emerged as a new degree of freedom for metamaterials, promising new pathways
in wave control. However, electromagnetism suffers from limitations in the modulation speed …

The article reviews general properties of time-varying dispersive materials. We first briefly
discuss different dispersion models that have been proposed in the literature, the role of the …

Non-reciprocal metasurfaces can encode optical functions on forward-and backward-
propagating waves, and could be used to create non-reciprocal antennas and radomes for …

Equip** millimeter-wave (mmWave) systems with full duplex capability would accelerate
and transform next-generation wireless applications and forge a path for new ones. Full …

We report on the design and performance of an on-chip microwave circulator with a widely
(GHz) tunable operation frequency. Nonreciprocity is created with a combination of …

Breaking the reciprocity of wave propagation is a problem of fundamental interest, and a
much-sought functionality in practical applications, both in photonics and phononics …