In　this　article,　a　Ku-band　high　directivity　antenna　is　designed,　which　consists　of　a　radiation　waveguide　section,　a　mode　conversion　section,　and　a　coaxial　waveguide　conversion　section.　In　this　article,　the　theoretical　calculation　process　of　antenna　components　is　summarized　and　supplemented.　The　calculation　method　between　key　technical　indexes　and　structural　parameters　is　established.　The　key　technical　parameters　of　the　antenna,　including　input　return　loss,　half-power　beamwidth,　gain,　and　cross-polarization　level,　are　studied　and　explored.　The　radiation　performance　of　the　antenna　can　be　further　improved　by　optimizing　the　structural　parameters.　Finite-element　analysis　and　COMSOL　simulation　software　are　used　to　study.　In　order　to　reduce　antenna　reflection,　a　method　of　equal-Q　impedance　transformation　is　proposed　for　rectangular　and　circular　waveguide　converters　and　coaxial　waveguide　converters.　Finally,　the　proposed　feed　antenna　is　processed　and　verified,　and　the　measured　results　are　in　good　agreement　with　the　simulation　results.　　©　2022　IEEE.