An end fire circularly polarized (CP) substrate integrated waveguide (SIW) horn antenna and a method of manufacturing thereof are described. The antenna includes an input section for receiving radio frequency (RF) waves from a source; and a body extending from the input section for receiving the RF waves from the input section, the body comprising a plurality of radiating units, the plurality of radiating units being configured to radiate circularly polarized waves (CP) in a far field, wherein apertures of the plurality of radiating unit being located along an edge of a planar dielectric substrate, and wherein the horn antenna is in a planar form.