Thin-Film Techniques for Microwave Integrated Circuits

With the application of thin-film integrated circuit techniques, microwave circuits can be designed to be small, highly reliable and relatively inexpensive. The basic structure out of which the circuits are formed is the planar transmission line, which may be designed in either the microstrip or the stripline configuration. Besides planar transmission lines, both lumped and distributed-parameter passive components, together with their interconnections, can be formed in the centre conductor by photolithographic techniques, and beam-leaded active components can be bonded to the circuit patterns thus formed. Three examples of modern microwave integrated circuits are described, and the standard processes used to manufacture such circuits are explained in terms of one of the examples.