Element-level Phase Measurement of Array Antenna using Stabilized Planar Imaging System for Emerging Sub-6 GHz 5G Communications

In this paper, a precise phase measurement method at antenna element level in array antenna is proposed. A highly stabilized planar field imaging system with dual electro-optic sensors is developed to measure phase in the reactive near-field region of the array antenna. Two sensors are realized with segmented-electrode modulator structure. One sensor is used for field measurement while the other probe is employed for phase stabilization. The proposed MIMO dual-polarized antenna array comprised of 8 patch elements, 8 antenna ports, 16 feeding network circuits, and a PCB with ground plane. Electric field of array antenna with two different polarization states measured at S-band along the different distance between sensor and antenna array.