AXIALLY SYMMETRIC TRANSIENT ELECTROMAGNETIC FIELDS IN A RADIALLY INHOMOGENEOUS BICONICAL TRANSMISSION LINE

In the present paper a novel mathematical model of physical processes of transient electromagnetic waves excitation and propagation in a biconical transmission line with radially inhomogeneous magneto-dielectric fllling is proposed. The model is based on time domain mode expansions over spherical waves. The basis functions of the mode expansions are calculated analytically. The mode expansion coe-cients are governed by Klein-Gordon-Fock equation with coe-cients depending on a radial spatial coordinate. The explicit flnite difierence time domain computational scheme is derived to calculate the mode expansion coe-cients. Dependences of cutofi frequencies of higher modes of TE and TM waves on the line geometry and dielectric fllling are studied. In order to calculate electromagnetic fleld in the line with higher accuracy, just flnite number of terms in the mode expansions is required. Electromagnetic fleld excited by the transient electric ring current is calculated in both homogeneous and radially inhomogeneous biconical transmission line. It is shown that there is a possibility to increase the bandwidth of the line via introduction of partial dielectric fllling without changing the line geometrical size.