Alam Jahangir, Khaliel Maher, Zheng Feng, Solbach Klaus, Kaiser Thomas
Institute of Digital-Signal Processing, University of Duisburg-Essen, 47057 Duisburg, Germany.
Benha Faculty of Engineering, Benha University, Benha 13511, Egypt.
Sensors (Basel). 2023 Aug 31;23(17):7562. doi: 10.3390/s23177562.
Chipless radio frequency identification (RFID) technology is expected to replace barcode technology due to its ability to read in non-line-of-sight (NLOS) situations, long reading range, and low cost. Currently, there is extensive research being conducted on frequency-coded (FC) co-polarized radar cross-section (RCS)-based tags, which are widely used. However, detecting co-polarized chipless RFID tags in cluttered environments is still a challenge, as confirmed by measuring two co-polarized tags in front of a perfect metal reflector (30.5cm×22.5cm). To address this challenge, a realistic mathematical model for a chipless RFID system has been developed that takes into account the characteristics of the reader and the tag, as well as reflections from cluttered objects. This extensive mathematical model developed for linear chipless RFID systems in clutter scenarios holds the potential to greatly assist researchers in their exploration of RCS-based tags. By relying solely on simulations, this model provides a tool to effectively analyze and understand RCS-based tags, ultimately simplifying the process of generating more authentic tag designs. This model has been simulated and verified with measurement results by placing a single flat metal reflector behind two co-polarized one-bit designs: a dipole array tag and a square patch tag. The results showed that the interfering signal completely overlaps the ID of the co-polarized tag, severely limiting its detectability. To solve this issue, the proposed solution involves reading the tag in cross-polarization mode by etching a diagonal slot in the square patch tag. This proposed tag provides high immunity to the environment and can be detected in front of both dielectric and metallic objects.
无芯片射频识别（RFID）技术有望取代条形码技术，因为它能够在非视距（NLOS）情况下读取信息，具有较长的读取范围且成本较低。目前，针对广泛使用的基于频率编码（FC）同极化雷达散射截面（RCS）的标签，正在进行大量研究。然而，在杂乱环境中检测同极化无芯片RFID标签仍然是一项挑战，在一个完美金属反射器（30.5厘米×22.5厘米）前测量两个同极化标签就证实了这一点。为应对这一挑战，已开发出一种针对无芯片RFID系统的实际数学模型，该模型考虑了读取器和标签的特性以及来自杂乱物体的反射。为杂乱场景中的线性无芯片RFID系统开发的这种广泛数学模型，有潜力极大地帮助研究人员探索基于RCS的标签。仅依靠模拟，该模型提供了一个工具来有效分析和理解基于RCS的标签，最终简化生成更逼真标签设计的过程。通过在两个同极化一位设计（一个偶极子阵列标签和一个方形贴片标签）后面放置一个扁平金属反射器，对该模型进行了模拟并与测量结果进行了验证。结果表明，干扰信号与同极化标签的ID完全重叠，严重限制了其可检测性。为解决这个问题，提出的解决方案是通过在方形贴片标签上蚀刻一个对角槽，以交叉极化模式读取标签。这种提出的标签对环境具有高抗扰性，并且在电介质和金属物体前均可被检测到。
