A noise parameter test setup allows accurately measuring the four noise parameters (Fmin, Rn, Γopt) of microwave transistors over a wide frequency range using two wide-band directional couplers, instead of SPDT switches, to merge the s-parameter (signal) measurement path and the noise measurement path, avoiding thus the uncertainty of the switching repeatability of the SPDT switches and improving the measurement accuracy. Calibration of the system is the same as when using switches. Additional power control precautions of the VNA sources are necessary to avoid injecting large signal power into the sensitive noise receiver during s-parameter measurements and jamming the weak noise power during noise measurement.
Filed: 28 August 2014
Allowed: 30 August 2016