Method-of-moments analysis of the narrow-wall slot array in a rectangular waveguide

The method-of-moments has been used for the analysis of the nonresonant narrow-wall slot array in a rectangular waveguide. As this approach works with the fundamental integral equations that describe the entire array, no assumptions about the aperture electric fields are required. Also, the equivalent circuit representation for the individual radiating slots used in earlier designs is not required in the present method, as it deals directly with slot aperture voltages. The effects of internal higher-order and external mutual couplings, and finite wall thickness are rigorously incorporated in the design. Expressions are presented for the input reflection coefficient, transmission coefficient, and the far-field radiation pattern of the array. Numerical results are compared with the experimental results of a 78 element narrow-wall slot array. Good agreement has been observed between theory and experiment.