Adaptive Correction for Radiation Patterns of Deformed Phased Array Antenna

The radiation patterns of an active phased array antenna (APAA) will inevitably deteriorate in service, due to the physical deformation of the antenna surface. Therefore, it is crucial that the APAA has an adaptive correction capability for the deterioration of the radiation patterns. This paper investigated an adaptive correction method for the radiation patterns of a deformed APAA, according to a small amount of measured strains from fiber Bragg grating (FBG) sensors. In this method, two kinds of strain-electromagnetic coupling models, which can change the excitation currents of antenna elements, were established using the phase correction and fast Fourier transform, respectively. The strain-electromagnetic coupling models are applied to quickly calculate the adjustment values of excitation currents, and then the corrected excitation currents are sent to the beam control circuit for compensating the influences of the antenna surface deformations. An X-band APAA experimental platform was developed. Some experiments were carried out, and the advantages of two coupling models were also compared and analyzed. The experimental results demonstrated that the proposed method can effectively correct the deterioration of radiation patterns caused by various antenna surface deformations. This method is suitable for developing an adaptive correction system in some applications such as the wing-APAA of an aircraft or the space-based flexible APAA.