In Endrenyi's  approach, considering a series of identical spans, the tower impedances and overhead ground wires are reduced to an equivalent lumped impedance
. Verma and Mukhedkar  included the mutual coupling between the neutral conductors and the phase conductors.
In the remaining part of the present paper, the effects of the transitional length [L.sub.t], the step change of the inner conductor diameter ([D.sub.2in] - [D.sub.1in]), and finally the slot angle of the split section [[theta].sub.t] on the input impedance seen at the (unbalanced) coaxial line side of the balun are investigated when it is terminated with specific lumped impedance at its (balanced) split side.
The excitation and lumped impedance load models are attached to the geometric model as described in .
The broadband balun for an arc dipole is simplified as a 50-[ohm] lumped impedance
since the input impedance (looking at point "A", see Figure 1) of the broadband balun was designed to be 50 Q.
Both define a lumped impedance
, that in the case of an array of perfect conducting metallic disks, is capacitive.
It is assumed that antenna elements can be represented by lumped impedances
, and Touchstone software is used to simulate and optimize the microstrip feed network under such conditions.