Semiconductor junction circulators

A semiconductor junction circulator is analyzed, and a predicted 25 dB isolation bandwidth of 6% at 94 GHz is shown using idealized, lossless GaAs at 77 K. A narrowband, lossy, theoretical design example at 40 GHz shows that losses do reduce performance but not to such a degree as to render the device useless. In this narrowband solution the losses due to electron collisions are modeled. The circulation conditions in this example are designed using intersecting impedance curves rather than the tracking solutions achieved in the lossless case. The technology discussed here may be compatible with high-T/sub c/ superconductors and with MMICs (monolithic microwave integrated circuits).<>