Analysis of mutual coupling in planar slot array antennas

The analytical model described treats higher-order mode mutual coupling between radiating slots and centered inclined coupling slots for both hard and soft orientations. The model is formulated from expressions for the magnetic fields in the regions bordering the slot aperture. These expressions are in integral equation form and contain Green´s functions for regions bordering the slot apertures. The integral equations for the equivalent magnetic surface currents in the slot apertures are solved using the method of moments. The deviations of the phase of the calculated radiated field from dominant-mode mutual coupling is presented for hard and soft orientations. This deviation due to higher-order modes represents the departure of this analysis from current design procedures, which only treated dominated waveguide modes. Results for the radiated field and the field scattered from the coupling slot are presented.<>