An antenna problem in waveguide

The induced e.m.f. method has been extended and applied to derive the driving point impedance of a common waveguide circuit used for mounting small microwave devices. The problem is similar to an antenna feed impedance problem with well defined boundaries (the waveguide walls). The resulting mathematical relationship has been conceptually interpreted as an equivalent coupling circuit, terminated by impedances which are associated with the many modes within the waveguide. Properties of this circuit and its terminations are discussed. An experimental investigation was also carried out to check and support the results of the theoretical analysis providing excellent agreement between the theory and the measurements. This formulation permits accurate design of many components which previously required empirical methods.