Beam scanning antennas based on pseudo traveling wave resonators

A pseudo-traveling wave resonator and its application to beam scanning antennas are reviewed. The resonator is a new type of transmission-line resonator, and is composed of a phase-nonreciprocal composite right/left handed (CRLH) transmission line and reflectors at both ends. The resonant frequency is independent of the resonator´s size. In addition, the resonator has traveling wave type field profile with uniform magnitude and finite gradient of phase distribution along the line. The phase gradient is determined by the phase nonreciprocity of the employed CRLH transmission line. We can control the phase gradient by changing an external dc magnetic field applied to ferrite materials included in the line. Leaky wave radiation from such resonators with open-boundaries forms an obliquely directional beam. Control of the phase distribution leads to the beam scanning. The proposed antenna has an advantage of low beam squint and high radiation efficiency, compared to conventional leaky wave antennas.