This work studies the electromagnetic field of a radiofrequency (RF) antenna on 7-inch liquid crystal display (LCD) and presents a new approach where the RF antenna is designed on LCD. This approach takes the magnetic field effect of LCD as an input parameter when building and simulating antenna models using the software Ansoft HFSS. After obtaining the PCB of the antenna, place the antenna on LCD, so that the antenna and LCD overlap up and down and measure the equivalent physical parameters as a whole. Last, use the vector network analyzer and Smith circle graph to tune the antenna system for completing the impedance matching of the whole system. This method breaks through the limitation that the card swiping area and the display area cannot be in the same area due to electromagnetic interference. It has changed the appearance design concept of the mobile point of sale (POS), and the antenna size can be 20%–100% of the POS display area. A contactless card read-write experiment for the proposed method has been carried out. Results showed the return loss is less than −30 dB, and the effective read-write distance of the antenna can reach about 5 cm. This design method provides a broader application prospect for mobile POS.

中文翻译：

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LCD射频天线的研究与设计

这项工作研究了 7 英寸液晶显示器 (LCD) 上射频 (RF) 天线的电磁场，并提出了一种在 LCD 上设计射频天线的新方法。这种方法在使用 Ansoft HFSS 软件构建和模拟天线模型时，将 LCD 的磁场效应作为输入参数。得到天线的PCB后，将天线放在LCD上，使天线与LCD上下重叠，整体测量等效物理参数。最后，利用矢量网络分析仪和史密斯圆图对天线系统进行调谐，完成整个系统的阻抗匹配。该方法突破了由于电磁干扰导致刷卡区域和显示区域不能在同一区域的限制。改变了移动销售点（POS）的外观设计理念，天线尺寸可以达到POS显示面积的20%~100%。对所提出的方法进行了非接触卡读写实验。结果表明回波损耗小于-30dB，天线有效读写距离可达5cm左右。这种设计方法为移动POS提供了更广阔的应用前景。