According to an embodiment of a method of manufacturing a power transistor module, the method includes mechanically fastening a first terminal, a second terminal and at least two different DC bias terminals to an electrically conductive flange; connecting the flange to a source of a power transistor device; electrically connecting the first terminal to a gate of the power transistor device; electrically connecting the second terminal to a drain of the power transistor device; mechanically fastening a bus bar to the flange which extends between and connects the DC bias terminals; and electrically connecting the bus bar to the drain via one or more RF grounded connections.