Scattering from a Round Metal Post and Gap

Improved expressions are derived for the microwave fields scattered by a uniform electric-field incident on and parallel to a round metal post, with gap, in waveguide and in two related structures. A pair of variational expressions are found for the scattering and for the gap reactance under even excitation. The results are compared with those due to Lewin, and with data in the Waveguide Handbook.