Monolithic integrated circuit device having microwave power amplifier including a matching circuit using distributed lines

摘要

A microwave multi-stage power amplifier has matching circuits for input and output stages and one or more inter-stage matching circuits. The amplifier and a signal output pad and first and second voltage supply pads are formed at one and the same semi-insulating substrate. A first FET in the output stage has its drain connected to the first voltage supply pad through a first distributed line and further connected to the signal output pad through a second distributed line in which the first and second distributed lines contribute to formation of the matching circuit for the output stage. A second FET in a stage preceding to the output stage has its drain connected to the second voltage supply pad through a third distributed line serving as a connection conductor. The first distributed line has a width larger than that of the third distributed line and has a length which limits an impedance seen at the drain of the output stage FET towards the first voltage supply pad at an operation frequency of the amplifier to a value other than infinity.