Post wall waveguide

A post-wall waveguide (also known as substrate integrated waveguide (SIW) or a laminated waveguide) is a synthetic rectangular electromagnetic waveguide formed in a dielectric substrate by densely arraying metallized posts or via-holes which connect the upper and lower metal plates of the substrate. The waveguide can be easily fabricated with low-cost and mass-production using through-hole techniques where the post walls consists of via fences. The post-wall waveguide is known to have similar guided wave and mode characteristics to the conventional rectangular waveguide with equivalent guided wavelength.

For instance, the equivalent width of a rectangular waveguide compared to a SIW is described in the approximation:

a R W G = a S I W − 1.08 ( 2 r ) 2 / p + 0.1 ( 2 r ) 2 / a S I W

where p is the distance between the posts in the post wall, r describes the radius, and a R W G as well as a S I W are the widths of the rectangular waveguide and SIW respectively.