Metallic losses in a waveguide slot array

The objective of this paper is to determine the power loss to the finite conductivity of the metal in a waveguide slot array. The method of analysis is based on the introduction of a waveguide slot module. Attention is focused on a single module in which the slot voltage and complex mode amplitudes A10and D10(henceforth the 10 subscript is implied for A and D) are assumed to be known values. The losses for the module are computed from the loss-free magnetic field solution. The fields in the interior of the guide are formulated in terms of Green\´s functions for rectangular waveguide. Explicit expressions for the dominant TE10and scattered higher order modes are derived. In the exterior plane of the module, the near field of the slot is formulated in terms of the exact field solution for a magnetic dipole. The exterior losses are computed numerically. Numerical results for a two-by-four array are presented.