Abstract: A power divider/combiner assembly is provided which matches the impedance seen at the input/output port with the impedance seen at the peripheral end of each of plural radial transmission lines. Impedance matching is accomplished through the use of an inverted microstrip on a substrate suspended over an air dielectric. The thickness of the air dielectric is varied along each transmission line in discrete steps from the common dividing/combining end to the peripheral end of each transmission line. The air dielectric thickness can be chosen independently for each section of line so that a characteristic impedance of from 40 ohms to greater than 130 ohms is achieved.