GB657607A - Improvements in or relating to electromagnetic wave guides - Google Patents

Abstract

657,607. Aerials. STANDARD TELEPHONES & CABLES, Ltd. Feb. 25, 1949, No. 5151. EClass 40 (vii)] [Also in Group XL (by] In an arrangement comprising a first waveguide of uniform cross-section, and a section of uniformly-tapered wave-guide coupling the first wave-guide to a further wave-propagating means, the susceptance introduced by the discontinuity at the junction between the first wave-guide and one taper of the tapered section is counteracted by introducing at the junction an additional susceptance of opposite sign. In Fig. 1 wave energy flows from a uniform waveguide 2 into a section 4, the narrow sides of which are tapered, and which leads to a further guide or horn, or which may itself consti. tute a horn. The discontinuity due to the taper introduces at the junction a negative susceptance which is neutralized by the introduction of an inductive diaphragm 6, the dimensions of which can be calculated. The discontinuity at the junction of the wide end of the taper and a uniform guide introduces a positive susceptance which can be corrected by a capacitive diaphragm, Fig. 2 (not shown). In Fig. 3 the wide face of the guide is tapered and the discontinuity introduces a positive susceptance which is corrected by a capacitive diaphragm 8. Conversely the discontinuity between the wide end of the taper and a uniform guide introduces a negative susceptance which is corrected by an inductive diaphragm, Fig. 4 (not shown). In Fig. 5 the uniform section 2 is coupled to a section 10 which is tapered in both directions, and which may constitute a horn, or may be joined to a further wave-guide. As the two tapers introduce susceptances of opposite sign, the horn may be designed to avoid mismatch. Alternatively. a diaphragm of the right kind may be used to correct for the residual introduced susceptance. These corrections are effective over a fairly wide wave-band.