Mutual coupling of shunt slots

Stevenson's method of analysis is extended to the case of a pair of shunt slots in the broad face of rectangular waveguide. The voltages in the slots are calculated including the effect of mutual coupling. Formulas suitable for calculation of mutual coupling are presented and the results of calculations for certain cases of overlapping quarter-wave spaced slots and nonoverlapping half-wave spaced slots are presented. Measurement of the scattering matrix of the slot pairs inside the waveguide and the radiation patterns external to the waveguide for the overlapping case tend to confirm the results of the theory. Calculations of the effect of mutual coupling on the patterns of three half-wave-spaced slot arrays indicate that mutual coupling is usually negligible for this type of slot.