Accurate characterization of the interaction between coupling slots and waveguide bends in waveguide slot arrays

In a waveguide slot array, it is sometimes required to introduce bent short -circuit terminations in the feeding network. This significantly affects th e behavior of the coupling slots used in this network, with a very large va riation in the coupling coefficient with respect to the standard case. A pr ocedure to accurately evaluate the effect of such bends is presented, thus allowing to include them without any loss in the overall design accuracy. I t is based on the method of moments, using a magnetic-field integral equati on expressed in terms of the vector potential, which appears to be the most efficient way for waveguide problems. The development is aimed at a very e ffective implementation, which allows to include it in design tools for wav eguide slot arrays without increasing the total computational load, and has been assessed through comparison with experimental results.