An Efficient Reactive Near-Field Measurement Method for Active Phased Array Antennas

Near-field measurements of active phased array antennas are typically carried out in the radiation region several wavelengths away from the antennas. The reactive near field distributed on the antenna surface carries high-resolution information, which is suitable for the array element measurement. However, limited by the aperture size of the conventional near-field probe (such as the open-ended waveguide), it is unable to obtain the high-resolution reactive near-field distribution of the active phased antennas. In this letter, we propose an efficient reactive near-field measurement method utilizing scanning optic-induced plasma scattering technology. A Ka-band active transmitting phased array antenna was measured. This method enables the direct observation of reactive near-field distributions with high resolution, allowing for high-efficiency measurement of the antenna operational states in tens of seconds. It is demonstrated that the proposed method can achieve the reactive near-field measurement efficiently and has significant potential for applications in antenna array diagnosis.