Finite Bandwidth Related Errors in Noise Parameter Determination of PHEMTs

摘要

We analyze errors in the determination of the four noise parameters due to finite measurement bandwidth and the delay time in the source circuit. The errors are especially large when characterizing low-noise microwave transistors at low microwave frequencies. They result from the spectral noise density variation across the measuring receiver band, due to resonant interaction of the highly mismatched transistor input with the source termination. We show also effects of virtual de-correlation of transistor's noise waves due to finite delay time at the input.