Exact solution for the characteristic impedance of rectangular coaxial cone transmission line

The exact and approximate expressions for the characteristic impedance of a rectangular coaxial cone transmission line are obtained using the conformal mapping method. The formula is exact and simple, so, it enables the characteristic impedance of a broadband transverse electromagnetic (TEM) cell to be calculated accurately and easily. This broadband TEM wave cell, has increasing applications in both electromagnetic interference and electromagnetic compatibility measurements.