A Low-Loss 74-11O-GHz Faraday Polarization Rotator.

We have developed a switchable Faraday polarization rotator for 74-110 GHz with a typical room-temperature insertion loss of 0.6 dB and a maximum of ~1.3 dB. The device uses a cylindrical ferrite rod in the HE11 mode with an axial magnetic field applied by a solenoid. The ports are square metallic waveguides transitioning to ceramic tapers, which then couple to the ferrite rod. The device is designed for use at a temperature of 20 K, where typical loss is < 0.5 dB. The design rotation is ±45° about the zero-bias value, but up to 90° is possible. The switching time is < 10 μs. [ABSTRACT FROM AUTHOR]