Frequency-Domain Digital Calibration and Beamforming with Wideband Antenna Array

This paper presents a joint channel and mutual coupling estimation technique for wideband antenna array to achieve high speed wireless communications in the millimetre-wave frequency bands. The estimated channel frequency responses and mutual coupling matrix can be used to digitally calibrate a wideband antenna array in the frequency-domain, followed by digital beamforming. Experiments are carried out using a four-element receive array prototype in the E-band (71-76 GHz) to demonstrate the frequency-domain digital calibration and beamforming performance. The results show that both the mutual coupling and wideband effects are effectively mitigated by the proposed technique and a 11.5 dBi array gain is achieved which is very close to that of an ideal four-element antenna array.