Comments on "Capacitance between Perpendicular Conducting Planes Separated by a Gap"

A recent paper [1] attempted to solve the problem of the capacitance between a semi-infinite ground plane and a symmetrically placed strip perpendicular to its edge, by use of conformal transformations and an approximate variational Green's-function formulation. This note points out that the results given in the paper are in error by more than a factor of 2, and that no approximation is necessary to solve the stated problem. The exact solution is given.