Analysis and design methods of planar array antennas with slotted waveguides taking into account mutual coupling

This paper described analysis and design methods for planar array antennas with slotted waveguides consisting of shunt slots as antenna elements which are cut on the wider surface of a rectangular waveguide. A matrix was shown for the mutual coupling among shunt slots. Also, another matrix was used relating the input and output waves at the array feeder point and the input and output waves between the shunt slots and free space. Through these two matrices the input reflection characteristics and excitation distribution of the array considering the mutual coupling of the total array with the feeder system could easily be obtained. Utilizing the variation of the mutual coupling among the shunt slots when sizes and displacements of the shunt slots from the guide axis were varied to be small, a simple algorithm with fast convergence was presented. Through experimental measurements the validity and effectiveness of the present analysis and design methods were confirmed.