In this article a rigorous and effective analysis of microwave ferrite stub tuned stripline junctions and circulators is presented. By using the equivalent parallel plate waveguide and mode matching method, the eigenvalues and scattering parameters of the junction are calculated. A method of design of the stub tuned circulators is given, which is verified by the experimental results. Theoretical and experimental results show that this kind of circulator can be easily designed to have an octave bandwidth.