Analysis of mutual coupling in planar slot array antennas

An analytic model has been developed to characterize mutual coupling in planar slot array antennas with greater accuracy than previously available. This new model incorporates the effects of mutual coupling between coupling slots in waveguide junctions and nearby radiating slots. The model was obtained from a formulation of the fields in slot apertures using a recent form of waveguide Green's functions. Numerical solutions to the aperture fields were implemented using the method of moments. Parametric studies of standard- and reduced-height waveguides were performed in order to identify those slot geometries having significant mutual coupling. In order to assess the accuracy of the analytic model, an experimental fixture was designed and tested. Measured mutual coupling values agreed with values obtained from the model.