Dispersion-Free and Tunable Nonreciprocities in Composite Right-/Left-Handed Metamaterials and Their Applications to Beam Squint Reduction in Leaky-Wave Antennas

In this paper, the enhancement of bandwidth for beam squint reduction in leaky-wave antennas has been numerically and experimentally demonstrated based on the pseudo-traveling-wave resonance by using nonreciprocal composite right-/left-handed metamaterial lines with almost dispersion-free phase-shifting nonreciprocities. We consider two different types of metamaterials governed by the edge-guided mode propagation in normally magnetized ferrite microstrip lines and operating at frequencies far above or below the magnetic resonance. Both metamaterials are separately designed and implemented in leaky-wave antennas based on the pseudo-traveling-wave resonance. The numerical simulation and measurement results verify the beam squint reduction for both cases with the enhanced bandwidths of 6%-10%.