A classic planar gyromagnetic resonator, encountered in the construction of three-port circulators, is one with top and bottom electric walls and a magnetic sidewall symmetrically loaded with a triplet of single magnetic walls. The main purpose is to experimentally characterise the complex gyrator circuit of a three-port junction using a resonator made up of a circular region, a triplet of single magnetic walls and a triplet of short 5° long UEs. It is compatible with the design of degree-2 circulators with commercial specifications and one experimental example is included for completeness sake. The effect of the UE embodied in the resonator under consideration is to decouple the coupling angle of the resonator terminals from any external microwave circuits, thereby facilitating the practical design of degree-2 circulators. A similar magnetised resonator loaded with a triplet of triple magnetic walls instead of single ones is also dealt with. It has the effect of reducing the spacing between the first three cut-off numbers of the isotropic geometry. © 2009 The Institution of Engineering and Technology.