Substrate Integrated Waveguide (SIW) is more applicable for implementation of millimeter integrated systems. It consists of top and bottom dielectric metal layers perforated with metallic holes called vias. It uses cut off frequency as TE10, which is same as rectangular waveguide. The difference between both is that substrate integrated waveguide uses two parallel arrays of conductive via holes instead of metallic walls. The non-planar transmission lines such as wired cables and coaxial cables were initially used for transmission but later metallic waveguides like rectangular waveguide which showed better result when compared to traditional cables were used. Planar structures like substrate integrated waveguide were used as an alternative option to replace non-planar nature and bulky system. Substrate Integrated Waveguide is a planar form of waveguide satisfies several requirements for space applications. Substrate Integrated Waveguide with slot antenna is the simple configuration highly suitable for satellite application.
V. Arvind, Sowmiya, R., Vignesh, P., Kavin, S., and Dr. Jayakumar M., “Yagi Slot Antenna Based on Substrate Integrated Waveguide Cavity for Wider Bandwidth Applications”, Proceedings of 2016 International Conference on Advanced Communication Control and Computing Technologies, ICACCCT. pp. 303 - 307, 2017.