Nonreciprocal and magnetically scanned leaky-wave antenna using coupled microstrip lines

A periodic nonreciprocal leaky wave antenna is presented based on coupled microstrip lines on a ferrite substrate. This printed layout was validated to exhibit nonreciprocal transmission properties in its guided-wave region (|β|>;k₀). To accomplish radiation, the printed dual transmission lines are operated in the fast wave region (|β|<;k₀), where strong spectral asymmetry (ω(K)≠ω(2π-K)) is also observed. This leads to novel nonreciprocal radiation characteristics. Specifically, more than 10 dB difference is observed between the simulated transmit and receive gain in the E-plane. The antenna can be also magnetically scanned between 20° and 90° (endfire) in the elevation plane by changing the external magnetic field strength. The associated gain varies between 8.34 dB and 9.95 dB at the operating frequency 2.8 GHz as the beam is scanned.