【作者】 杜晓琳；

【导师】 高攸纲；

【作者基本信息】 北京邮电大学 ， 生物医学工程， 2012， 硕士

【摘要】 现今,随着移动通信技术的发展,移动通信终端已经不再局限于手机,而是包括了上网卡、MIFI>上网本、摄像机等嵌入了SIM卡或USIM卡模块的设备,呈现出了多样化趋势。3G上网卡作为一种在3G时代新兴的上网终端设备,得到了广泛的应用。上网卡内置了通信模块及天线,能够协助笔记本在3G信号覆盖的地方,通过3G网络,利用SIM卡连接到互联网。而为了保证通信质量,需要准确评估3G上网卡的天线性能。OTA(Over The Air)测试技术是一种评估天线辐射性能和接收性能的有效测试方法。虽然目前国内还没有强制性的OTA测试标准,但各个厂商和相关国际组织(如CTIA、PTCRB. 3GPP、COST273)对此问题进行了大量测试和研究。同SAR (Specific Absoration Rate)值测试标准一样,OTA测试最终将成为强制标准来执行。与手机终端不同的是,上网卡的通常使用状态为与笔记本USB端口连接,笔记本会对上网卡的OTA性能产生一定影响；人头离天线距离较远,而人手位于天线近场区,人手会对上网卡的OTA性能也会有影响。因此本论文的一个研究重点便是通过理论分析、数值仿真及具体试验分析不同笔记本、人手模型对上网卡OTA性能的影响大小差异,得出量化的分析结果,最终向3GPP标准组织提交合理的上网卡OTA测试方法提案。除了能够通过OTA测试确定天线的远场性能,还需要用SAR参数确定天线的近场性能。但是SAR值与OTA参数中的TRP值(Total Ration Power)是矛盾的。一般降低发射功率,会使SAR值降低,但是天线的辐射性能会变差,也就使TRP值变低。为解决这个问题,需要对降低SAR值的方案进行进一步研究,本论文运用电磁场仿真软件进行终端天线的SAR值仿真,并与OTA仿真结果进行比对,综合评价终端天线性能,做出理论分析和说明,具体提出降低SAR值的方法。更多还原

【Abstract】 Now, with the development of mobile communication technology, the mobile communication terminal is no longer limited to mobile phone. Many devices embedded SIM card or USIM card modules like the 3G USB dongles, MIFI, video cameras can get access to the Internet through advanced mobile communication network. These terminals revealed a trend of diversification. The 3G USB dongle as a new kind of Internet device in 3G era is widely used. The 3G USB dongle integrated in communication module and antenna can help the notebook get access to the internet in 3G signal coverage areas. In order to ensure the quality of communication, evaluating the performance of antenna effectively is of great importance. OTA test technology as an active test method is becoming an effective method to evaluate the transmitting and receiving performance. Though at present there is no any mandatory OTA test standards, each manufacturer and relevant international organizations (such as the CTIA, PTCRB,3 GPP, COST273) have done much test and research work about this problem. Like the SAR test standard, OTA will eventually become a compulsive standard to execute. But unlike a normal mobile phone, the 3G USB dongle is usually in connection of a notebook to work, and at this time, the laptop will have an effect on the OTA performance of that USB dongle. Meanwhile, human hand may affect the dongle but not human brain in mobile phones. So a main part of this paper is to research how much difference the different laptops and a human hand may introduce through theoretical analysis, numerical simulation and the experimental analysis. From various points of view, the impact of the OTA performance cause by different laptops will be studied in detail, and finally the relevant results can be proposed for 3GPP and other groups.In addition to an OTA test to show the far field performance of an antenna, a SAR parameter is needed to reveal the near field performance. But the SAR value and the TRP value OTA parameters (total radiation power) are the contradiction. Generally, if the transmission power is reduced, the SAR value will decrease. But meanwhile, the radiation performance of the antenna will be worse, and also will make the TRP value become low. To solve this problem, the method of reducing the SAR value effectively is needed. From this point, this paper use electromagnetic field simulation software to study a method of reducing SAR value.更多还原