In-Situ Self-Test and Self-Calibration of Dual-Polarized 5G TRX Phased Arrays Leveraging Orthogonal-Polarization Antenna Couplings

In this paper, an in-situ self-test and self-calibration technique for 5G dual-polarized dual-beam TRX phased-arrays is presented. The procedure, labeled dual-polarized built-in self-test (DP-BIST), exploits the mutual coupling between different antennas of orthogonally polarized beams sharing the same aperture to enable relative channel offset extraction, channel gain/phase characterization and failure detection for the channels of each beam. DP-BIST was applied to a 16-element dual-polarized dual-beam linear phased-array at 29 GHz and predicted the relative channel states (gain, phase) with rms errors < 0.2 dB /2.5 deg. and the relative channel offsets with rms errors of 0.8 dB /10 deg. DP-BIST is all-electronic, and can be done using a single aperture without any assistance from neighbouring arrays. It can be used for initial calibration as well as for re-calibration in the field, and is well suited for 5G polarization-based multiple-input multiple output (MIMO) systems.