中文摘要：

利用返波振荡器（BWO）系统对不同电阻率的GaAs在太赫兹波段的透射谱进行了测试，并对太赫兹波透射谱进行了计算和分析，得到不同电阻率的GaAs材料在太赫兹波0．23～0．375THz波段范围的折射率、吸收系数和介电常数实部和虚部等光学特性参数。实验结果表明，不同电阻率的GaAs在整个测试太赫兹波频段内的折射率，吸收系数，介电常数实部和虚部均随着电阻率的增加而增加。高电阻率的GaAs材料对太赫兹波的吸收很小，其最小吸收系数可达到3．87×10^-4cm^-1。同时也表明采用返波振荡器系统研究分析GaAs在太赫兹波段特性是可行的。研究不同电阻率的GaAs在太赫兹波段的光学特性，对设计高效率太赫兹波天线具有重要意义。

英文摘要：

By using backward-wave oscillator （BWO）, the transmission spectra of various resistivity GaAs were tested. Then the transmission spectra were examined and analyzed. The refractive index, absorption coefficient, and dielectric functions of various resistivity GaAs and terahertz dielectric properties of GaAs were measured and compared in the frequency range from 0. 23 THz to 0. 375 THz. The experimental results indicate that all the refractive index, absorption coefficient, and dielectric functions of the various resistivity GaAs increase with the increase in frequency. The absorption coefficient of high resistivity GaAs is very small, and its least absorption coefficient equals 3. 87× 10^-4 cm^-1. The authors results demonstrate the applicability of the backward-wave oscillator THz transmission spectroscopy for GaAs characteristic analysis by calculating the reflectance spectra. This work establishes the basic spectra data for the various resistivity GaAs and is very significative to the design of high efficiency terahertz wave antenna.