Abstract: A composite diode module is provided having an impedance matching member integrally formed within the module. The module includes a base member, a heat sink holder member having an aperture, a gold plated diamond heat sink which is disposed in the aforementioned aperture, and an encapsulant holder member having a second aperture. IMPATT diodes are disposed in dielectric spacers bonded to one end of the heat sink in alignment with the second aperture. A bias pin member is then bonded on the second end of the IMPATT and an encapsulant having selected electrical properties is provided in the second pair of apertures to secure the diode and to provide the diode module with a predetermined impedance characteristic. In a preferred embodiment, the module includes a pair of IMPATT diodes. With this arrangement, the module may be used in power combiners.