The Analysis Of 3G USB Dongle OTA Performance And Low SAR Terminal

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.