This presentation covers the design and realization of microwave and millimeter-wave circuits using three dimensional metal micro-machining processes. Circuits fabricated using these process have several advantages over competing technologies. One particularly important advantage is the ability to realize TEM transmission lines that operate from DC to over 300 GHz and can be arbitrarily routed on a substrate. These lines are fully enclosed providing high isolation even at millimeter wave frequencies. A second advantage is the ability to accurately reproduce a wide variety of circuits including couplers and filters. Topics covered in this presentation will include the fabrication processes, circuit design and implementation, and the advantages and disadvantages of this new technology.