Hierarchical Code-Modulated Embedded Test and Calibration on a 64-Element Phased Array

Hierarchical code-modulated embedded test (CoMET) is introduced to characterize and calibrate scaled phased arrays in parallel using orthogonal code modulation with scalar detection. Hierarchical testing can reduce CoMET test time without sacrificing accuracy. A 64-element 28 GHz phased-array receiver is used to demonstrate the technique, where the array is divided into four- or eight-element sub-arrays and measured in a hierarchical manner. Hierarchical CoMET is validated against VNA measurement to achieve 1.5 degrees and 0.25 dB phase and gain RMS error across 64 elements and 64 phase settings. Electrically-swept beams are improved after calibration based on hierarchical CoMET.