基于太赫兹参量源的高频段雷达散射截面测量OA

In response to the limitations of the radiation source power and the difficulty in controlling the measurement beam in high-frequency terahertz Radar Cross Section(RCS)measurements,a large-quiet-zone RCS measurement system based on the ultra-widely tunable high-power terahertz parametric source and quasi-optical reflective beam expansion is demonstrated.The system can achieve high-sampling-rate,high-sensitivity and high-frequency terahertz RCS measurements.A two-stage terahertz beam expansion and collimation optical path based on off-axis parabolic mirrors is designed by using Zemax software,which can uniformly expand terahertz beams at different frequencies to over 100 mm.Using the smooth aluminum spheres as the standard calibration targets,the reliability of the measurement system is verified at 3.2 THz and 5.7 THz.On this basis,RCS measurements of smooth aluminum plates,aluminum columns and missile models are completed,and the variation trends with terahertz frequencies are discussed.The measurement results show that the dynamic range of the measurement system can reach up to 68 dB,and the measurement accuracy is better than 3 dBsm.The RCS measurement system and measurement results can support the design of high-frequency terahertz radar systems and the scale-model measurements of large-sized targets.