A Tunable Compact Polarizer in a Circular Waveguide

The possibility to design a tunable polarization plane (PP) rotator in waveguides with circular symmetry is proven. The appearance of artificial “optical activity” in the interaction of a pair of conjugated planar chiral irises by the fringing fields is used. The rotator can be reconfigured by rotating the irises relative to each other providing the rotation of the PP up to cross-one. Being relatively narrowband, the rotator has a longitudinal dimension $\lambda _{0}/50$ – $\lambda _{0}/10$ .