Research on phase array antenna diagnosing method at spherical near-field measurement

Antenna hologram diagnosing is an important feature at near-field measurement system that can help antenna designer find out the problem in antenna design or antenna network configuration. Hologram diagnosing at planner near-field measurement is widely used in radar antenna measurement, in spherical near-field measurement there is also needed. Based on the electromagnetic mode expansion method under the spherical coordinate system, this paper calculates the hologram inversion algorithm under spherical near-field conditions. Then, the aperture distribution of the antenna is calculated in the simulation model, and the calculation results are consistent with the theoretical model. In the actual test, the X-band array antenna is tested, and the aperture inversion results of the array antenna under different configurations are obtained, and the amplitude inversion accuracy of the algorithm is better than 1 dB.