An In-Situ Self-Test and Self-Calibration Technique Utilizing Antenna Mutual Coupling for 5G Multi-Beam TRX Phased Arrays

This paper presents an in-situ self-test and self-calibration technique and its application to 5G TRX phased arrays. The developed built-in self-test (BIST) procedure, labeled Quad-BIST, enables the relative channel calibration, channel gain/phase characterization and failure detection of 5G phased-arrays. Quad-BIST relies on antenna mutual coupling to neighboring arrays arranged in Quad-fashion to extract the calibration coefficients and perform channel characterization. Quad-BIST was successfully applied to a 4x(4x4) array at 29 GHz and predicted the Quad's channel states (gain, phase control) with rms errors of 0.1 dB/ 1° and the relative channel ratios with rms errors of 0.9 dB/ 11°. The technique is compact and all-electronic, requires no moving parts or a far-field range, and can be applied for initial calibration as well as for re-calibration in the field (as a result of aging, environmental changes, etc.), and is well suited for 5G MIMO base-station systems.