GB781024A - Microwave unidirectional coupling device - Google Patents

Abstract

781,024. Waveguide accessories. HUGHES AIRCRAFT CO. June 1, 1955, No. 15743/55. Class 40 (8). The ferrite element in a unidirectional microwave Faraday-effect isolator is cooled by means of a fluid passing through the waveguide section in which the element is mounted. The waveguide section 12 is of square, round or polygonal cross-section and encloses a dielectric supporting member 16 for the ferrite element 14. The strength of an axial magnetic field is adjusted to produce a Faraday rotation of 45 degrees in the plane of polarization of forward-' going energy and a further rotation of 45 degrees in the same absolute sense of any energy reflected from the load. The reflected energy is coupled to a dissipative load by means of a probe and septum (Fig. 1, not shown) arranged to discriminate between orthogonally-polarized modes. Cooling air is introduced and extracted from the guide section by means of oppositelysituated manifolds 30, 32 which communicate with the interior of the section by holes 42 of diameter equal to about 1/12 of the guide wavelength. These holes may be covered with a conductive mesh. The supporting member 16 is also provided with holes. In a modification, Fig. 3, a liquid dielectric is used as a coolant. The liquid is circulated in passages bored in dielectric supporting members 50, 52, 54 which are a tight fit in the waveguide section 12.