On MM-wave quasi-linear over-the-air modulated measurements and coupling effects

As integrated transceiver-antenna combinations become increasingly used at mm-wave frequencies, characterization of quasi-linear quantities while not having direct access to the transmitted mm-wave signal is more important, particularly to assess nonlinear effects of transmitter element coupling. Calibration processes to get magnitude and phase flatness within the signal bandwidth and over carrier frequency ranges are required as is a sufficiently linear receiver array. Using a 2×2 MIMO array at V/E-band (with ~50-150 MHz modulation bandwidth) as an evaluation vehicle, improvements enabled detection of AM-AM changes on the scale of tenths of a dB and AM-PM changes on the scale of degrees that were invisible otherwise. Multiple dB corrections in intermodulation values were also observed.