Design and characterization for a high-temperature dual-band radome wall structure for airborne applications

Abstract

Modern aircraft have reached higher and higher flight speed, resulting in the urgent demand of design and characterization for high-temperature airborne radomes, especially for those with dual-band or multi-band properties. In this paper, an A-sandwich radome wall structure made of quartz is designed for both centimeter and millimeter wave applications at high temperatures. Its transmission performance in the 4–40GHz frequency range at ambient temperature to 800°C is characterized by a broadband free-space microwave measurement system, which is mainly composed of a vector network analyzer, spot-focusing lens horn antennas, and a furnace for heating sample. A calibration method is proposed to eliminate the temperature-dependent distortion of microwave signals by the microwave-transparent walls of the furnace, and the errors caused by the wall position variations as well. Transmission measurements show that the radome wall structure is feasible for dual-band applications in the 4–10GHz and 24–40GHz frequency spans with the transmission efficiency higher than 70% at temperatures up to 800°C, and demonstrate the effectiveness of the design method. It can be expected that the free-space microwave measurement system in conjunction with the proposed calibration method is capable of damage detection for aerospace structures under high-temperature conditions.