Coupling Structural-RCS Modeling And Integration Performance Analysis For Array Antennas With Mechanical Distortion

The stealth technology plays a very important role in modern electronic warfare. It gets attention and developing by more and more countries. With the development of the stealth technology and the application of new materials, radar cross section of the target has been very small, so the array antennas have become a major contributor to the RCS of its low visibility platform equipped. Structural deformation caused by the complex service environment will make the array antenna radiation performance deterioration, and it will also greatly affect the performance of the array antenna scattering, however array antenna RCS computational complexity, while the influence of the scattering properties of structural deformation is difficult to estimate and calculate, and there has few study in domestic and outside. Therefore, the study of the structure of the array antenna coupling between the displacements field and its RCS will become very important. Based on this, in this article we study the coupling relationship between structure filed and electromagnetic scattering field displacement field of the array antenna, and analysis of the impact of structural deformation on the array antenna scattering properties. Meanwhile, combine the radiation field performance of the array antenna; we study the approaches to integrate the radiation and scattering performance of array antennas. The main contents are as follows:(1)Without considering the mutual coupling effects and edge effects between array antenna unit cases, from the perspective of the phase error analysis point of view, we established structure displacement field and RCS coupled model(SD-RCS) of array antenna. By comparing the result of SD-RCS coupling model and electromagnetic analysis software FEKO simulation, it verifies the accuracy and effectiveness of coupling model. Combined with SD-RCS coupling model, we analysis the effect of deformation to scattering properties of the array antenna, by analysis the saddle surface deformation which is the most often appear kind of deformation in the projects. The simulation results show that with the front saddle surface deformation increases, the radiation performance degradation, but scattering performance improved. When the maximum deformationmaxz >λ/ 4, the gain decreased significantly, while the RCS reduced significantly.(2)For structural deformation will make the array antenna radiation performance degradation while improving its scattering properties, based on the SD-RCS coupling model, we proposed the performance of the array antenna radiation and scattering properties of integrated optimization method Combined with particle swarm optimization, by optimizing the installation height of the antenna array antenna elements to achieve an array antenna radiation and scattering properties. The simulation shows that for 7×7 plane array, in the loss of 1.29 d B of gain which satisfy the radiation performance, the RCS reduction could reach 20.06 d Bsm, greatly improved the scattering properties of the array antenna.(3)When the array antennas canted, the scattering main lobe direction will deviation maximum direction, the sidelobe of array antenna has become the biggest threat, meanwhile the low sidelobe is very important to the radiation performance of array antenna, Taking into account the little effect of the amplitude weighting and phase weighting in the achieving the low sidelobe of the scattered field of array antennas, as well as the insufficient of density weighted unequal spacing array, we based on the SD-RCS coupling model proposed methods while achieving density weighted by the sparse array radiation field and scattered field of low sidelobes. Combined with genetic algorithm, by optimizing the array antenna elements, we achieved the radiation field and the scattered field with low sidelobe. The simulation result shows that, as for the 0.5λ cell pitch, 10λ diameter of the circular opening spaced rectangular grid array, such that the radiation field E plane MSL of RCS is-24.98 d B MSL less than-25 d Bsm, while achieving the low sidelobe of radiation field and the scattering field.