Abstract: An improved millimeter wave device package design in which the package includes a dielectric substrate disposed upon a supporting base such that the substrate extends substantially along the peripheral edge of the base, defining a central aperture. A solid conductive layer substantially covers the first surface of the dielectric substrate and a series of conductive transmission lines are formed on an opposing second surface of the substrate. A dielectric layer is disposed upon and substantially covers the transmission lines and the second surface of the substrate upon which they are formed. A seal ring is disposed upon and the dielectric layer and a conductor electrically connects the device to the transmission lines. A lid is sealed atop the seal ring completes the hermetical seal for the device.