Symmetric radio frequency coaxial splitters

Provided herein are various enhanced assemblies and techniques for forming high-power radio frequency coaxial splitters. In one example, an apparatus includes an input coaxial port having a center conductor coupled to a first longitudinal end of a generally cylindrical conductor member formed along a longitudinal axis within a housing forming a cavity about the conductor member. Output coaxial ports are included having center conductors coupled to generally square output branches arrayed at a second longitudinal end about the conductor member in a plane perpendicular to the longitudinal axis. A thermal shunt is included comprising a thermal connection between the housing and a recess formed into the conductor member along the longitudinal axis at the second longitudinal end.