Measurements of a Cryogenic Linear Polarization Modulator for mm-Wavelengths

Cryogenic Faraday phase modulators have been implemented in waveguide and tested in both a constant current mode and an alternating current mode. The loss of the phase shifter for DC currents that results in either a or phase shift is on average 1.45 dB over the entire W-band. In the modulating mode, it operates at frequencies as high as 4 Hz with transition times between the two phase states of 1.32 x 10
^-2
s.