Theory of coupled monopoles

Accurate numerical values of mutual and self-admittances are obtained for an array consisting of two monopoles having different lengths and radii. The monopoles are actually protrusions of the inner conductors of coaxial cables. The sheaths of the cables are connected to a perfectly conducting ground screen. Restrictions in the theory are the following: the monopoles must be thin,
a/\lambda \ll 1
where
a
is the radius and
\lambda
the wavelength,
b < 3a
where
b
is the radius of the coaxial cable sheath, and
d > 10a
where
d
is the separation of the monopoles. The procedure employed to obtain the mutual and self-admittances is to derive simultaneous integral equations for the current distributions and to solve the integral equations numerically. The results are given for the most part in graphical form. Comparisons are made with existing theory and with experimental data. Excellent agreement in all cases is observed.