An ultra-wideband time domain reflectometry chipless RFID system with higher order modulation schemes
An ultra-wideband time domain reflectometry chipless RFID system with higher order modulation schemes
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DOI：
10.1109/gemic.2016.7461640
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发表时间：
2016-03
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通讯作者：
Maximilian Popperl;C. Carlowitz;M. Vossiek;C. Mandel;R. Jakoby
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作者：
Maximilian Popperl;C. Carlowitz;M. Vossiek;C. Mandel;R. Jakoby
本文提出了一种低成本、低复杂度的基于 FMCW 的超宽带 (UWB) 无芯片时域反射计 (TDR) 射频识别 (RFID) 系统，适用于实现更高阶的调制方案。高阶调制显着增加了无芯片 RFID 中的信息内容。相移键控 (PSK) 和脉冲位置调制 (PPM) 在无芯片 TDR RFID 中的适用性促使我们推出 8-PSK 以及 8-PSK 和 2-PPM 组合。与低阶调制方案（例如仅实现 4 位的开关键控）相比，总体数据容量增加至 16 位。该标签基于蜿蜒的传输线，由于仅由微带结构组成，因此印刷成本低廉。我们构建了一个合适的询问单元，因为无芯片 RFID 标签可实现的存储密度在很大程度上取决于读取器架构和性能。该阅读器的带宽为 1.25 GHz，中心频率为 7.825 GHz，可提供最大功率以满足大多数国家/地区的 UWB 法规。阅读器的询问信号是由压控振荡器 (VCO) 生成的调频连续波 (FMCW) 信号，并通过锁相环 (PLL) 进行稳定。通过这种设置，审讯单元的构建成本低廉。由于阅读器和标签都会影响信息内容，因此需要研究完整的 RFID 系统。除了两个系统部件的详细描述之外，测试还展示了 TDR RFID 系统的性能。
This paper presents a low-cost, low-complexity FMCW-based ultra-wideband (UWB) chipless time domain reflectometry (TDR) radio frequency identification (RFID) system, which is suitable for implementing higher order modulation schemes. Higher order modulation significantly increases the information content in chipless RFID. The applicability of phase-shift keying (PSK) and pulse-position modulation (PPM) to chipless TDR RFID leads us to introduce an 8-PSK and an 8-PSK-and-2-PPM combination. The overall data capacity is increased to 16 bits compared to low-order modulation schemes, for example, on-off keying, which achieve only 4 bits. The tag, which is based on a meandered transmission line, can be printed cheaply as it consists solely of micro-strip structures. We built an appropriate interrogation unit since the achievable storage density of a chipless RFID tag greatly depends on the reader architecture and performance as well. The reader features a bandwidth of 1.25 GHz at a center frequency of 7.825 GHz, which allows for maximal power to meet most countries' UWB regulations. The reader's interrogation signal is a frequency-modulated continuous-wave (FMCW) signal generated by a voltage-controlled oscillator (VCO) that is stabilized by a phase-locked loop (PLL). With this setup the interrogation-unit build is inexpensive. As the reader as well as the tag impact the information content, the complete RFID system needs to be investigated. In addition to a detailed description of both system parts, tests demonstrate the performance of the TDR RFID systems.