IMD phase analysis at mm-wave frequencies

IMD phase measurements have been shown to be useful in characterizing DUT memory effects and related non-linearities at lower microwave frequencies. In the past, the accuracy of some of these measurements at higher frequencies has been limited by dynamic range, calibration stability, combiner inadequacies, and other issues. A modified technique will be presented that relies on broadband, rationed VNA-based measurements to get stable phase data together with a calibration process reminiscent of other non-linear techniques. Residual IMD floors below −120 dBm for offsets of more than a few MHz, <3 degree phase stability and <0.2 dB amplitude stability were observed at W-band.