Active phased array antennas (APAAs) can suffer from the effects of harsh thermal environments, which are caused by the large quantity of power generated by densely packed T/R modules and external thermal impacts. The situation may be worse in the case of limited room and severe thermal loads, due to heat radiation and a low temperature sink. The temperature field of the antenna can be changed. Since large numbers of temperature-sensitive electronic components exist in T/R modules, excitation current output can be significantly affected and the electromagnetic performance of APAAs can be seriously degraded. However, due to a lack of quantitative analysis, it is difficult to directly estimate the effect of temperature on the electromagnetic performance of APAAs. Therefore, this study investigated the electromagnetic performance of APAAs as affected by two key factors—the uniformly distributed temperature field and the temperature gradient field—based on different antenna shapes and sizes, to provide theoretical guidance for their thermal design.

To enhance the intelligence and digital management level of radio telescopes and ensure the safe and stable operation of antennas, this paper proposes a real-time state evaluation method for the antenna structure of radio telescopes based on digital twin (DT) technology. Firstly, based on the five-dimensional model of DT, a digital twin system (DTs) framework for radio telescopes is designed. Secondly, the quadric error metrics (QEM) mesh-simplification algorithm and mesh-reconstruction technology are employed to obtain a lightweight twin model of the antenna. Furthermore, a random forest (RF) regression surrogate model is established using finite element point cloud data samples. The K-nearest neighbor (KNN) algorithm and radial basis function (RBF) interpolation algorithm are utilized to construct the virtual–physical mapping model of the antenna, enabling rapid prediction and evaluation of the antenna structure state. Finally, a DT for real-time antenna structure state evaluation is developed using the Unity3D engine, with an experimental prototype of a reflector antenna as the object. Experimental results show that the average prediction accuracy of the physical field surrogate model of the system is 0.98, and the average computation time is 0.4 s. The system meets the precision and computational efficiency requirements for the real-time and accurate evaluation of the antenna structure state.