Non-iterative design of a 2-D array of waveguide slots with cavities to give active admittance equal to an isolated slot

This paper presents the non-iterative design for a waveguide slot array with cavities. The cavity dimensions to make the active slot admittance equal to that of an isolated slot are irrespective of the slot coupling except for a strong coupling. We can use the parameters of the isolated slot in the half-free space for required coupling. Once the slot parameters are determined, they are not iteratively changed by including the external mutual coupling as the conventional waveguide slot array. This design drastically simplifies the procedure. The uniform and Taylor distributions with -35.0 dB sidelobes are realized to demonstrate the advantageous of this design. HFSS simulation confirms a high gain with 32.6 dB and high aperture efficiency with 88.4 % for the uniform distribution. The measurement for the Taylor distribution demonstrates that the sidelobe level in the H-plane is -31.1 dB in the side of the feed and -26.4 dB in the side of the matching slot, and -32.4 dB in the Eplane.