A method of estimating the power radiated directly at the feed of a dielectric-rod aerial

In a recent paper, Brown and Spector have shown that an end-fire aerial is a purely guiding structure, with radiation occurring only at the free end and at the feed end of the aerial. Such a system of radiation may be represented by a simple transmission-line analogue. The present paper illustrates this representation in the case of a waveguide-fed dielectric-rod aerial of uniform rectangular cross-section for use at 3cm wavelengths and shows its application to finding the fraction of the total power supplied to the aerial which is radiated at the feed. This fraction was found to be 23% when the dielectric rod had a rectangular cross-section of 0.9 in × 0.4 in.