一、引言许多微波计量标准和仪器以及无线电设备,譬如量热式微波功率标准、噪声标准、低噪声通讯中,往往需要引进一段有特殊要求的传输线而又要精确扣除它的衰减。本文结合精密同轴小功率计中隔热传输线小衰减的测试,介绍一种简便的方法,即利用我厂生产的GX2A铋锑薄膜热电偶功率探头(以下简称TfT探头)作检测元件,以电位差计(或数字式电压表)作指示器的单通功率比法。在被测衰减量小于0.5分贝时,由该方法本身引入的误差不大于0.001分贝。二、工作原理和测试系统衰减的基本含义是在一个传输系统中,由 I. INTRODUCTION Many microwave metrology standards and instruments, as well as radio equipment such as calorimetric microwave power standards, noise standards, and low-noise communications, often require the introduction of a section of transmission lines with special requirements but also to accurately deduct its attenuation. In this paper, a small coaxial line power meter with small attenuation attenuation test, the introduction of a simple method that I use the factory production of GX2A bismuth antimony thin film thermocouple power probe (hereinafter referred to as TfT probe) as the detection element, the potential Differential meter (or digital voltmeter) as a single-pass power indicator method. In the measured attenuation less than 0.5 dB, the error introduced by the method itself is not more than 0.001 dB. Second, the working principle and test The basic meaning of attenuation is in a transmission system, by