Microwave and Millimeter Wave Hybrid Integrated Circuits for Radio Systems

Advances in solid-state technology and related processing techniques in recent years make it possible to produce small size, minimum weight, low production cost circuits for communication systems. These advances became possible because of simultaneous improvements in the fields of planar diffusion, photolithographic pattern delineation, and vacuum and sputtering techniques. A typical end product of this process is the beam-leaded, sealed junction monolithic integrated circuit. Although the process is extremely complex, its main advantage is t h a t many identical circuits, untouched by human hands, can be produced in a short time at low cost. 1703 1712 T H E BELL SYSTEM TECHNICAL JOURNAL, JULi'-AUGUST 1969 In spite of these advances only limited progress has been achieved in applying similar concepts and techniques to circuits at microwave and millimeter wave frequencies. There are two reasons for this. One is that the planar silicon technology is not fully applicable in the microwave and millimeter wave frequency range because many types of solid-state devices are manufactured from group I I I - V intermetallic compounds. The other reason is that stray reactances at high frequencies are extremely important, that is, metallic overlays on semiconductors have the electrical properties of short sections of low impedance transmission lines which can create special circuit problems. We show that such problems can be solved and t h a t hybrid integrated circuits for solid-state radio systems can be built with solidstate devices mounted on or bonded to suitable metallized dielectric substrates.