This paper focuses on the extreme environmental adaptability and high-performance requirements of aerospace antenna arrays.A domestically-produced low-temperature co-fired ceramic （LTCC） substrate material is selected to develop a low profile，lightweight，miniaturized，circularly-polarized，4×4 scale highly-reliable antenna array with a center frequency of 12 GHz.The structural design and testing results of the antenna array are analyzed，and the effects of material changes on the electrical performance of the antenna array under irradiation environments and the reliability of the antenna array structure under extreme temperature conditions are investigated by simulations.The results show that the parameter performance changes of domestically-produced LTCC materials have little influence on the electrical performance and structural reliability of the antenna array under irradiation and extreme temperature conditions.The relative impedance bandwidth （S11<-10 dB） of the antenna array is 41.6%，the 3 dB axial ratio relative bandwidth is 33.8%，and the maximum gain is 15 dBi.The antenna array has excellent performance and high structural reliability，and can be widely used in aerospace circularly-polarized communication systems.