Variable Termination Unit for Noise-Parameter Measurement

The National Institute of Standards and Technology (NIST) has upgraded its capability to measure noise parameters on low-noise amplifiers with a variable termination unit (VTU) in the frequency range of 1-12.4 GHz. Such a unit allows improved time efficiency and accuracy in the noise-temperature measurements used to de-embed the noise parameters of amplifiers. We present the design and characterization of the VTU. The measured results of one particular amplifier at integer frequencies ranging from 8 to 12 GHz show satisfactory accuracy. The VTU method is also validated by comparison with the results from the manual method.