Admittance of coaxial feed between two finite parallel conductors

It is known that, using a reduction process, the admittance contribution of the higher order modes of the current on a coaxial probe can be calculated in an analytical way. The authors prove that, once the lower order modes are determined, they can also be taken into account analytically. The final result is that no numerical effort at all is needed to determine the admittance of the coaxial feed in terms of the probe current modes.