Analysis of the oscillation conditions in distributed amplifiers

It has been shown that under certain conditions oscillation phenomena can occur in distributed amplifiers. It has also been demonstrated, using a simplified transistor model and a symmetrical amplifier with lumped circuit elements, that the oscillation depends directly on the transconductance g/sub m/ of the active devices. The origin of this oscillation was found to be the loop formed in the distributed amplifier structure. The analysis has been experimentally verified in a practical 1-20-GHz monolithic MESFET amplifier. Finally, design guidelines have been established to avoid stability problems and to improve the capabilities of high-gain distributed amplifiers.<
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