Broadside Radiation by Excitation of EBG Leaky Mode

A broadside radiation from an electromagnetic band-gap (EBG) waveguide is achieved. The EBG waveguide, which operates around 30 GHz, is designed using a square lattice of metal vias to build a spatial power combiner. A surface mode was excited by adding a row of holes to the square lattice of metal vias. The row of holes was modulated to couple the surface mode to a leaky mode that radiates in free space. The return loss of the optimized structure is less than -10 dB around a frequency of 30 GHz, and the radiation pattern has the main beam along the broadside. The measured data of the fabricated structure confirm the directional radiation pattern.