Ultra-compact 90° twist based on a pair of two closely placed flat chiral irises
A new approach to the task of rotating the polarization plane of planar electromagnetic wave or dominant modes in a square (circular) waveguide is suggested. The physical idea is based on strong interaction of near-fields in two flat chiral irises with right and left rotation located at distances that are much less than the wavelength. Due to multi-mode character of the interaction it is possible to provide the several percent bandwidth when rotating the polarization plane by 90° at the level not worse than –0.1 dB.
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