Microwave Billiards with Broken Time Reversal Symmetry

First results on microwave billiards with broken time reversal symmetry are presented. The billiards are quasi two dimensional with an attached microwave isolator acting as a unidirectional transmission line. Spectral level dynamics was studied by changing the billiard length. For all spectral properties observed, i.e., nearest-neighbor distance, asymptotic curvature, and closest-approach distance at avoided crossings, we have found behavior characteristic of the Gaussian unitary ensemble.