Nonreciprocal Magnetless CRLH Leaky-Wave Antenna Based on a Ring Metamaterial Structure

A nonreciprocal ferrite-loaded open rectangular composite right/left-handed (CRLH) waveguide structure was introduced by the authors in 2009, and later shown to operate as a novel and useful antenna system. However, this structure suffers from the classical drawbacks of ferrites (bulkiness, heaviness, high cost, nonintegrability, and limitation below the X-band). In order to remedy these issues, this letter replaces the ferrite in that structure with a recently introduced magnetless nonreciprocal ring metamaterial exhibiting essentially the same properties as a ferrite and demonstrates, theoretically and experimentally, its equivalent leaky-wave antenna operation.