同轴馈线 meaning in English

coaxial feeder
coaxial supply line

However , in hf band , the band of the antennas is narrow , and the input impedance of monopole antenna with limited height undergoes rapid variation with frequency
但是,在hf频段,有限高无加载单极子天线带宽相对较窄,输入阻抗随频率剧烈变化,难于和50的同轴馈线匹配。
But ridged waveguide antenna which is small in volume when working at a low frequency band can obtain a high resolution and is suitable in the rubber material measure . one of the features of the paper is that some improvements of fdtd are presented
脊波导天线与普通金属波导相比，在较低的频域可以有较小的工作尺寸，因而能达到较高的分辨率，且便于与同轴馈线连接，很适合用于橡胶吸收材料的测量中。