An improved stability broadband/mm-wave VNA structure

In the past, the stability and quality of broadband mm-wave network analysis measurements have sometimes been challenges because of required high frequency multiplexing schemes, physically large and inhomogeneous measurement structures and complex receiver chains. A newer structure for this class of VNA measurements will be presented where a broadband, miniature front-end receiver is used for more of the acquisition with a single receiver chain. Using this system structure, improved stabilities have been demonstrated including thru line S
₂₁
deviations below 0.02 dB and 0.5 degree over 24 hours from 70 kHz to 120 GHz and temperature sensitivities on the order of 0.01 dB/C and 0.1 deg/C over the same range. This could allow for longer intervals between calibration and improved measurement results.