In the early 1980s a good deal of excitement was generated and several optimistic projections were made predicting the rapid adoption of gallium arsenide (GaAs) Monolithic Microwave Integrated Circuit (MMIC) technology by microwave system designers, with correspondingly large profits for MMIC manufacturers. The high cost of maintaining a facility can only be offset by high volume production of MMICs. In contrast, GaAs MMICs are analog circuits that usually contain less than 10 transistors on a typical chip. Yield is an important concept for MMICs and refers to the percentage of circuits on a given wafer with acceptable performance relative to the total number of circuits fabricated. MMIC inductors are realized with narrow strips of metal on the surface of the chip. Air bridge spiral inductors are distinguished from conventional spiral inductors by having the metal traces that make up the inductor suspended from the top of the substrate using MMIC air bridge technology.