Plane-chiral pair with opposite rotations as a new way to rotate polarization up to 90°

A new approach to the problem of polarization transformation of a plane wave or waveguide dominant mode is proposed. The idea is based on the strong interaction of the fringing fields excited by irises with chiral right and left rotations, placed at a distance that is an order of magnitude shorter than the wavelength. Due to the multimode nature of the interaction we can provide 90 degrees rotation in bandwidth equal to several percents at the insertion loss level not worse than -0.1 dB.