Abstract
This chapter has presented the insight methodologies on how to design, implement, and evaluate a width-bandwidth mm-wave fully connected hybrid beamforming metrological testbed with a large antenna array. The focus has been given on discussions include testbed design, calibration procedures, experimental evaluations, as well as the critical factors to consider for their practical implementation. If RF harmonics and spurious signal issues are avoided, one envisages that the testbed could be setup to work between 25 and 30 GHz with 2-GHz instantaneous bandwidth. Each of the phase shifters and attenuators in the mm-wave fully connected hybrid beamformer has six separate DIO control bits. Apart from describing the calibration procedures for the phase and amplitudes of the established fully connected hybrid beamformer system, the linearity, phase, and attenuation performance of the beamformer system between 25.5 and 26.5 GHz have been evaluated as well as the beamforming and link performance of a 128-element planar phased array at 26 GHz where the measured radiation patterns with and without amplitude tapering are compared.