MULTI-BAND BALANCED ANTENNAS WITH ENHANCED STABILITY AND PERFORMANCE FOR MOBILE HANDSETS

全球范围内的无线通信仍在以惊人的速度发展，而该技术的天线元件对其成功至关重要。各种移动的天线结构已引起越来越多的关注，其显著特征是小尺寸和低成本。然而，还需要在天线辐射方向图和比吸收率（SAR）水平方面优化特性，以符合国际安全准则。此外，天线应该与手机的主体具有弱耦合，以在存在人体（包括握持手机的手）的情况下提供最佳的性能稳定性和阻抗匹配。一个很好的选择是使用平衡天线来减少移动的天线对手机的影响，因为不平衡的天线将电流驱动到手机底盘中，这与身体的不可预测的特性强烈地相互作用。与传统的不平衡天线相比，如果这些天线设计良好，则最大比吸收率（SAR）值在靠近人头放置时会大幅降低。该研究的目的是设计一种天线，该天线将使用布拉德福德混合电磁建模技术开发，与遗传算法相结合，以优化带宽的增强。用于2G、3G、B3G和IEEE 802.x移动的频段的这些天线的多频段和宽带变体也将被视为该项目的关键目标。

The move toward worldwide wireless communication continues at remarkable pace, and the antenna element of the technology is crucial to its success. Various mobile antenna structures have found increasing attention, significant characteristics being small size and low cost. However, the characteristics also need to be optimised with respect to the antenna radiation patterns and the Specific Absorption Rate (SAR) levels for compliance with international safety guidelines. Moreover, the antenna should have weak coupling with the body of the handset to provide the best performance stability and impedance matching in the presence of a human body, including the hand holding the handset. A good candidate is to use balanced antennas to reduce the effect of the mobile antenna on the handset, since unbalanced antennas drive current into the handset chassis, which interacts strongly with the unpredictable characterisitics of the body. The maximum specific absorption rate (SAR) values have been shown to be substantially reduced when placed next to the human head, compared with conventional unbalanced antennas, if these antennas are well-designed. The purpose of the study will be to design an antenna that will be developed using the Bradford hybrid electromagnetic modelling technique, allied to genetic algorithms to optimise the enhancement of the bandwidth. Multiple-band and wideband variants of these antennas for 2G, 3G, B3G and IEEE 802.x mobile bands will also be considered as a key target of the project.