生物医学工程用的横电磁波传输室及标准场的研制

The Study of TEM Transmission Cell and its Standard Field Used for Biomedical Engineering

横电磁波传输室(TEM cell)是用于模拟电磁波在自由空间传输状态的一种新的实验设备。当电磁波输入传输室后,一个小于矩形波导TE_(10)模截止频率的行波电磁场被建立起来。传输室和监测装置相结合组成了标准场测量系统。该系统为生物电磁学、电磁辐射的生物效应、防护及近场测量装置研制,提供了一个工作频率小于360MHz、特性阻抗51.85Ω、电压驻波比1.34、插入损耗小于0.5dB、场强可以准确计量、总不确定度小于±1dB的标准场。测量表明,该系统主要技术指标达到了美国8801、8802横电磁波传输室标准场的技术水平。它的研制对开展生物医学电磁学及电磁兼容研究有重要意义和实用价值。

TEM transmission cell is a new equipment for simulating transmission conditions of EM wave in free space. When electromagnetic wave has been fed into the cell, a uniform TEM field is established with a frequency lower than the cutoff frequency of TE_(10) mode of rectangular wave guide. The measurement system of standard fields was made by the combination of our newly built cell and specially designed monitoring instruments. A standard field with operating frequency <360 MHz, characteristic impedance 51.85Ω, VSWR 1.34, insertion loss<0.5 dB, accurately measurable field strength, and total uncertaint<±1dB was provided for studying bioelectromagnetics, biomedical effects of electromagnetic radiation, and instrumentation of protection and near field measurements. It was showed that the main technical specifications of this system attained technical levels of 8801 and 8802 TEM cell made in USA. The development pf this system is of important significances and practical values for biomedical electromagnetic and EMC researches.