Third Order Intermodulation Improvement in Distributed Amplifiers

The paper considers the third order intermodulation behaviour of a distributed amplifier (with loss in gate and drain lines) in which the principle non linearity is due to gm and shows theoretically that in a two tone intermodulation test at constant output power, C/IM3 increases as the number of sections in the distributed amplifier is increased. A similar result is obtained by the simulation of a n stage distributed amplifier. An improvement in C/IM3 of about 25dB is obtained by increasing the number of stages in a distributed amplifier, with loss, from one to five.