Analysis of interleaved arrays of waveguide elements

An analysis is presented of multiple interleaved arrays of waveguide radiators operating at different frequencies. The approach is a generalization of the analysis of an infinite array at a single frequency. The presence of the low-frequency elements affects the radiation characteristics of the high-frequency elements and generates grating lobes which do not appear in a single-frequency array. Furthermore, power is coupled ´into the low-frequency waveguides when the high-frequency elements are excited. Numerical examples are presented which show that these effects are not severe.