Abstract: Microwave or millimeter wave module packaging having a module with a baseplate, transition board and cover. The baseplate includes microwave or millimeter wave components attached thereto. The transition board includes a first connector attached to a first side thereof and operatively connected to the components, and a second connector attached to a second side thereof and operatively connected to the components through the board. The cover and baseplate form a cavity containing the board and components, and the second connector may be operatively connected to a third connector such as a printed circuit board disposed outside of the cavity and on a higher level assembly. The transition board may further include a fourth connector operatively connected to the components for providing a signal to an external component or device or receiving a signal from an external component or device.