Millimetre-wave circulator - has broadband matching achieved by tapering port waveguides and uses ferrite rod as core

摘要

The circulator has three or more ports and a ferromagnetic core at its centre. The core is exposed to a static magnetic field. One of the sides of each waveguide port tapers in a longitudinal direction. The taper is linear. The core consists of a ferrite rod fitted into a blind hole at the centre of the circulator, i.e. at the place where the ports intersect. An air gap is left between the ferrite rod and the upper edge of the waveguide. The ferrite rod has a round or triangular cross- section. The arrangement gives broadband matching whilst preserving simplicity of structure and manufacture.