GB963414A - Waveguide circulator - Google Patents

Abstract

963,414. Waveguide circulators. MULLARD Ltd. Aug. 23, 1962, No. 32479/62. Heading H1W. A four-port waveguide circulator comprises a composite element including a conductive matching post, a ferrite member or members and an outer annulus of dielectric material. The circulator is of the type comprising two sections of rectangular waveguide meeting in a common H or E plane with their axes perpendicular to each other to form a four-port junction. The composite element is arranged at the centre of the junction with its axis at right angles to the common plane of the waveguide axes. Fig. 3 shows the element in section as viewed from one of the ports of an H plane junction. It comprises a cylindrical brass matching post 1, two manganese-magnesium ferrite cylindrical members 3 and an annular dielectric member 2 of polystyrene. The outer diameter of the dielectric member may be greater or less than that of the ferrite members (Figs. 4, 5, not shown). It may surround both cylindrical members and extend from one waveguide wall to the other. Alternatively, it may surround only the ferrite members. The diameters of the conductive post and the ferrite cylinders may be equal. Fig. 7 shows a construction using one ferrite element surrounded by a dielectric annulus. In another modification (Fig. 8), the three members are of the same length. The matching post 1 may be in the form of a tube or of a conductive layer on a dielectric cylinder. Alternatively, it may comprise a conductive layer on the inside of the dielectric annulus or the ferrite member. In all the constructions the ferrite member (or members) makes face-to-face contact with one or both opposite walls of the waveguide and the arrangements are such that a path without airgaps is formed between opposite walls through the conductive member or through the conductive and ferrite members. As applied to an E plane junction, the element extends between the narrow walls of the guides.