Bandwidth of a low sidelobe level multimode radiating coupled waveguide array

The multimode radiation patterns due to a waveguide periodically coupled on the one hand with another waveguide and, on the other hand, with unidentical radiating slots were studied. The aim of the study was to calculate and realize a prescribed current distribution which would obtain a low sidelobe level in a multimode array. First, the theoretical concept is justified after a successful comparison with experiments. Secondly, optimum array parameters are taken into account in order to deduce the theoretical bandwidth and efficiency of the multimode array. Theoretical results and experiments are in good agreement. The optimum array parameters are critical and special attention is paid to the accuracy with which the array must be realized.