Abstract: By applying the impedance matching technique and using metallic wire grid electrical tunable unit, the optimization design of electrical tunable was performed for plate joints (or reinforcing rib) in large partitioning dielectric radome. On the premise of guaranteeing mechanical performance of joint structure, the transmission efficiency of optimized mixed dielectric structure containing metallic wire grids improves by about 20% compared with plate joints. In addition, by loading different metallic wire grids, the frequency range of best transmission for mixed structure can be adjusted, thus can be used to develop radomes of various frequency. This provides a novel technological pathway to design high-performance large dielectric radomes.