Measurement of Residual Phase Noise of Amplifiers at 80 GHz Using Interferometric Measurement Technique

The additive/residual phase noise of power amplifiers or multipliers adds noise in the signal path. For example for automotive RADAR sensors at 80 GHz designers of RADAR applications require the added phase noise in the TX path to be lower than <-130 dBc/Hz at 100 kHz offset or even lower to further increase the S/N for detection of small moving targets. The interferometric measurement approach in combination with a phase noise test system provides a way to characterize the additive/residual phase noise of amplifiers down to -150 dBc/Hz at 100 kHz offset even in the microwave range at 80 GHz.