截止区 meaning in Chinese

blacked zone
blocked zone
cut off region
cut-off r egion
cutoff region

And the intensity of electric field decayed by - 41 . 5db . when the length of forbidden region was increased , the output signal distorted seriously and some obvious high frequency components were found
当波导截止区的长度增加时，输出波形严重失真，出现了较为明显的高频成分。
The author thought that the high frequency components were included in the input signal originally . after having crossed the forbidden region , they have not been decayed but the main frequencies in the input signal have been decayed enormously
分析表明，输出信号的高频成分系输入信号本身所具有的，在通过截止区后未被衰减同时主频却发生了非常大的衰减而显现出来。
The followings were discovered in the simulations of undersized waveguide : when the pulse width of input signal , a gaussian packet , is rather wide , the output signal distorted little . a superluminal group velocity 3 . 21c was revealed when the wave packet crossing 50mm forbidden region
对凹陷波导（ undersizedwaveguide ）的模拟发现：输入脉冲宽度较大的高斯波包，模拟结果显示输出波形失真较小，经过计算得到电磁波包穿过长50mm的截止区时，电场的幅度衰减了- 41 . 5db ，群速度为3 . 21c 。