A feed horn with a horn body and a waveguide body, each with a front end and a back end, respectively. The horn body and the waveguide body coupled together, the waveguide body front end to the horn body back end. The waveguide body provided with a waveguide bore between the front end and the back end. At least one slot formed in the waveguide bore parallel to a longitudinal axis of the body bore, the at least one slot extending to the front end. The horn body provided with a horn bore between the front end and the back end. The horn body and the waveguide body formable via injection molding methods such as die casting.