On the cyclostationary properties of the 1/f noise of microwave semiconductor devices

This paper addresses, from an experimental perspective, the long-standing question on whether the 1/f noise of microwave semiconductor devices should be considered cyclostationary in compact models. By using a simple instrumentation setup and basic mixer concepts, it will be shown that the external equivalent current noise sources of such devices simply CANNOT be stationary. To demonstrate our ideas, a through experimental analysis was carried out on purely-resistive bridge circuits made up of microwave varactors and transistors under large-signal operation whose DC current component is kept constant. When computing the voltage noise power of specific circuit arrangements, errors in excess of 20dB may be induced if the stationary concept is adopted. The difference between the stationary or cyclostationary concepts will be simulated with the aid of the simulator ADS from Agilent.