A Ka-Band On-Wafer S-Parameter and Noise Figure Measurement System

A Ka-band on-wafer S-parameter and noise figure measurement system is described. The system includes an automatic network analyzer for S-parameter measurements and a waveguide noise source and receiver for noise figure measurements. A key difficulty in the system calibration is obtaining the excess noise ratio (ENR) provided by the noise source at the MMIC wafer probe interface. This problem is overcome by performing error corrected vector S-parameter measurements of the input transition network, which consists of a waveguide terminal on one end and a probe tip on the other. These S-parameters are then used to obtain noise calibration reference planes at the probe tips. To demonstrate the system, noise figure and gain measurements for three MMIC amplifiers are presented.