A power combiner/power divider has a disk shaped housing cavity and a housing of electrically conductive material, such as metal. A junction pin is positioned centrally in the power combiner/divider. Additional ports are positioned radially along the periphery of the disk shaped portion. Tapered waveguides may extend from the radially positioned ports to the centrally positioned junction pin. A hollow radial cavity provided in the cavity holds a dielectric insert that may have tapering extensions radiating from a central ring. The ring surrounds the centrally positioned port.