A modified QPSK modulation technique for direct antenna modulation (DAM) systems
A modified QPSK modulation technique for direct antenna modulation (DAM) systems
复制标题
用于直接天线调制 (DAM) 系统的改进 QPSK 调制技术
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Yuanxun Ethan Wang
中科院分区：
文献类型：
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作者：
Rui Zhu;Yuanxun Ethan Wang
直接天线调制(DAM)是为了克服高Q谐振天线的带宽限制，通过将存储能量与耦合或辐射能量解耦而提出的。然而，由于其开关特性，它在码元转换时对调制技术施加零电压或零电流开关条件，以实现高辐射效率。过去使用的是基于单周期RF脉冲的简单开关键控(OOK)。提出了一种适用于DAM系统的高阶相移键控调制技术。所谓的改进的QPSK调制技术可以在符号转换时保持零电流开关条件，同时创建四个象限相位来表示不同的符号。对采用这种调制技术的近场通信(NFC)系统的仿真已经显示了从眼图判断的更好的传输性能。
Direct antenna modulation (DAM) has been proposed to overcome the bandwidth limitation of high Q resonating antennas by decoupling the stored energy from the coupled or radiated energy. It, however, due to its switching nature, imposes a zero voltage or zero current switching condition to the modulation technique at the symbol transition in order to achieve high radiation efficiency. Simple on-off keying (OOK) based on monocycle RF pulses was used in the past. In this paper, higher order phase shift keying modulation techniques are proposed for DAM systems. The so-called modified QPSK modulation technique can maintain zero current switching conditions at the symbol transitions while creating the four quadrant phases to represent different symbols. Simulations for a near field communication (NFC) system employing such modulation techniques have demonstrated better transmission performance judged by the eye diagrams.