Integrated time-varying electromagnetic devices for ultra-wide band nonreciprocity

Abstract

Traditional passives operate in a time-invariant manner and are subject to the fundamental limit of reciprocity unless magnetic material is involved. A new class of electromagnetic devices that are operating in a time-varying fashion is introduced. These time-varying devices may be implemented on semiconductor platforms with their time-dependent property enforced through parametric modulation or high speed switching. It will be demonstrated through addition of the new time dimension the reciprocity can be lifted. Two novel circulators, one with the time-varying transmission line and the other sequentially switched delay line (SSDL) are proposed and demonstrated on-chip. Potential new applications such a full-duplex radios and tunable RF front-ends may be developed with these novel device concepts.