  This article presents measurement guidelines and verification procedures for
antenna cross-polarization discrimination (XPD) and penetration loss
measurements for millimeter wave (mmWave) channel sounder systems. These
techniques are needed to ensure accurate and consistent measurements by
different researchers at different frequencies and bandwidths. Measurements at
73 GHz are used to demonstrate and verify the guidelines, and show the
consistency of the antenna XPD factor and the penetration loss at different
transmitter-receiver (T-R) separation distances, thus providing a systematic
method that may be used at any frequency for reliable field measurements.
