Traceable mm-Wave Modulated-Signal Source for Over-The-Air Device Characterization

Within the 5G and 6G communications fields, a large breadth of wireless devices requires characterization and testing. The shrinking size of mobile devices and the use of multiple antennas leads to devices without test ports for separately characterizing the antennas, receivers, and transmitters. Also, test cables change the behavior of an antenna, and negate the meaningfulness of conducted-device testing. The use of over-the-air (OTA) testing has become ubiquitous for mobile wireless devices. Many of the relevant OTA metrics, such as receiver sensitivity, require a communication link with the device-under-test. A reference field for a communication link requires characterization of the phase and magnitude. At NIST, in the Metrology for Wireless Systems Project, we have focused on traceable measurements for vector fields, meaning the measurements of magnitude and phase, and therefore error-vector-magnitude, can be connected to primary standards. We have developed a connectorized, wide-band, precision, modulated-signal source, traceable through our uncertainty framework. We have several research areas for extending the traceability path into the free field to provide a reference waveform for OTA testing. I will present our current research areas in our project. These include the SAMURAI system that utilizes a synthetic aperture to add angular dependence to traceable vector measurement. As well as a hybrid reverberation/anechoic chamber for traceably emulating a factory environment in the mm-wave.