Multi-probe Linear Matrix Inversion Method in Sub-array Internal Element Calibration

This paper presents a sub-array internal element calibration method using linear matrix inversion method. Multi-probe is employed to detect the E-field distribution of the sub-array under test in the near field. A transmission matrix between the sub-array and probes is built. The key point of this method is getting low condition number transmission matrix. Furthermore, optimization strategy based on genetic algorithm is introduced to obtain more stable matrices. Simulation results show only 4 probes are needed for a 4-element array testing. Finally, a 4-element sub-array composed of rectangular waveguide antennas operating at 3.5 GHz was measured to validate the effectiveness of the proposed method, and the results show a high accuracy - the error between the proposed method and the reference test is less than ±0.2dB, ±2°.