This paper proposes the design of a single radiator monopulse antenna with a substrate integrated waveguide (SIW) multi-mode feeding system to reduce the aperture size and simplify the feeding structure. The proposed antenna can effectively reduce the overall system size by using a single patch radiator. compared to conventional systems that require multiple radiators. In addition. https://www.chiggate.com/miller-multimatic-235-255-tig-kit-supply/