Parallel-plate waveguide with a Bed of Nails for Radial-Line Slot Array Antennas

This communication explores the use of a parallel-plate waveguide with a bed of metallic nails on its bottom plate with the aim to design all-metal radial-line slot array antennas (RLSAs). This kind of antennas would provide a highly-efficient directive radiation of circularly-polarized waves at millimeter-wave band, adopting a very simple power distribution scheme. Specifically, in this communication, the radial propagation of the fundamental mode within this pinned waveguide is explored and the coupling to the slot array is studied and modeled. This study will enable an efficient analysis and design of all-metal RLSAs.