Novel nonreciprocal components based on hollow ferrite discs, i.e. ferrite ring resonators, are discussed. Some three-port and four-port components are analysed, and some design guidelines are presented. It is shown that a ring structure requires a smaller diameter and ferrite thickness than a disc structure for the same frequency. A ring also provides another variable in design and permits ports to be connected to the inside as well as the outside. Novel components and increased component density may therefore be possible at the expense of bandwidth.