采用微扰法研究了左手介质矩形波导的吸收特性。由于色散方程的限制，左手介质波导不能传输基模，它的吸收特性也与右手介质矩形波导明显不同。结果发现， 模式的衰减系数随长宽比(a/b)的增加而减小，而在右手介质波导中结果恰恰相反。除此之外，当不同模式的光波在同一左手介质矩形波导中传输时，每一模式都对应着相邻很近的吸收峰和吸收谷。同时高阶模的衰减系数较低阶模的大。但是，当不同模式的光波在同一右手介质矩形波导中传输时，它们的衰减曲线随着波导宽度的增加而振荡的变化，并且趋近于芯层衰减系数。另外一方面，在右手波导中，高阶模式的衰减系数较低阶模式小。

In this paper, the absorption property of the left-handed material (LHM) rectangular waveguide was studied by use of the perturbation method, and other novel properties were revealed. Due to the restriction of the dispersion equations, the LHM waveguide can not support the fundamental modes, and its absorption property is quite different from that of RHM (right-handed material) rectangular waveguide. It was shown that Ey11 modes attenuation coefficient changes from large to small as the length to width ratio (a/b) grows, while the result is reverse in RHM rectangular waveguide. In addition, when different modes are propagating in the same LHM waveguide there is an absorption peak for every mode, and in a small neighborhood of this peak, an attenuation trough can be found. In this case, higher-order modes possess larger attenuation coefficient than lower-order modes. But, when different modes are propagating in the RHM waveguide the attenuation curves are changing vibrantly and approach the core attenuation coefficient with the increasing of the width b. Otherwise, higher-order modes possess smaller attenuation coefficients than lower-order modes in RHM waveguide.