Theory of dielectric rod aerials

Theoretical and experimental investigations on the radiation characteristics of (i) circular cylindrical and (ii) conically tapered dielectric rod aerials excited in the HEn mode have been carried out in the X-band. (i) Expressions for the radiation characteristics of an untapered dielectric rod aerial have been derived with the aid of (a) Huyghen´s secondary radiators concept and (b) Schelkunoff´s equivalence principle. (ii) In the case of a conically tapered dielectric rod aerial, an expression for the radiation characteristics has been derived by using an approximate step by step method.