Room temperature solid-state plasma nonreciprocal microwave devices

Nonreciprocal microwave propagation at room temperature in a waveguide which contains of a thin slab n-InSb has been demonstrated by the construction of an isolator, a three-port circulator, and a variable power divider, all operating at K-band frequencies. A forward loss and an isolation of 3 and 15 dB, respectively, was observed for the isolator; the forward and backward losses between adjacent ports of the circulator were 3 and 20 dB, respectively, and the power ratio of the divider could be varied from 1 to 10 for a given direction of the magnetic field. Transmission losses of about 3 dB were present in the forward direction and in each case, all but 1 dB of these were shown to be due to reflections resulting from impedance mismatch.