Design of uniform aperture field distribution with no-grating lobes on traveling type of slit array antenna made by copper-clad dielectric substrate at 60 GHz

A traveling type of planar antenna fed by an over-sized metal waveguide, whose top plate consists of slit array etched on a copper-coated dielectric substrate, was designed at 60 GHz. Main emphasis was placed on the uniform aperture field distribution with no-grating lobes by taking suppression of unwanted slab modes in the dielectric substrate into account. To eliminate the grating lobes, the low loss Teflon sheet was filled in the oversized-waveguide, being a slow wave structure. The radiation pattern by 3-D calculation agreed with that by the Kirchhoff´s scalar approximate theory, and thus the validity of the design procedure was confirmed.