【摘要】 为提高BJ100波导形脉冲微波能量计测量长脉冲串微波能量的精度，改进了该脉冲微波能量计的结构。首先，确定了影响该型脉冲微波能量计测量不确定度偏大的主要因素是微波吸收腔的热散失；其次，分析了不同重复频率、不同脉冲数量脉冲微波能量实测数据，以及理论上连续吸收N个微波脉冲时吸收腔热散失能量占比与吸收腔热时间常数的关系。结果表明，微波吸收腔的热散失中，热时间常数较小是影响脉冲微波能量测量不确定度较大的根本原因。根据实测与理论分析，提出了一种结合矩圆转换、模式转换以及采用尺寸更大的圆锥形吸收腔的方法，以增大微波吸收腔的热时间常数。实验测试结果表明：包含因子k为2时，在测量持续时间为2.4 s、能量为100 J的X波段脉冲串微波能量时，使用改进方法的脉冲微波能量计测量扩展不确定度由原先的17%降低至6.6%，验证了该优化方案对长脉冲串微波能量测量精度的提升效果。更多还原

【Abstract】 To improve the measurement accuracy of the microwave energy when measuring long pulse burst by a BJ100 waveguide-type pulsed microwave energy meter, whose the measurement uncertainty components are analyzed in this paper. It is found that heat dissipation within the microwave absorption cavity is the major factor leading to large measurement uncertainty. The analysis of measured microwave energy data with different repetition rates and pulse numbers, as well as the theoretical inverse relationship between the proportion of heat dissipation energy in the absorption cavity and the thermal time constant of the absorption cavity when absorbing N microwave pulses continuously, all indicate that a small thermal time constant is the fundamental factor affecting the large measurement uncertainty of pulsed microwave energy. Therefore, a method combining rectangle-circle conversion, mode conversion, and using a larger-sized conical absorption cavity is proposed to increase the thermal time constant of the microwave absorption cavity. The experimental results show that when measuring X-band pulse train microwave energy with a duration of 2.4 s and an energy of 100 J, the improved method reduces the measurement expanded uncertainty from 17% to 6.6%(k=2), verifying the effect of this optimization scheme on improving the measurement accuracy of long pulse train microwave energy.更多还原