A circulator comprises a thermally conductive waveguide housing having a plurality of hollow waveguide arms that communicate with a central cavity, with the hollow waveguide arms each having at least one inner sidewall surface that is angled toward the central cavity. A ferrite element is disposed in the central cavity of the waveguide housing. The ferrite element includes a central portion and a plurality of ferrite segments that extend from the central portion. The ferrite segments each protrude into a separate waveguide arm along the at least one inner sidewall surface, with at least one side of each ferrite segment attached to the at least one inner sidewall surface.