Ultrahigh frequency radio frequency identification (UHF RFID) uses backscattered electromagnetic (EM) modulation techniques to communicate between readers and tags. The suppression of the carrier signal leaked from the transmission channel to the receiving channel is the key factor that determines the reader’s sensitivity. In this letter, a broadband, fast carrier cancellation technique is proposed. The reader system uses two transmission ports: one is for the transmission of the interrogating signal and carrier waves (CWs) and the other port can dynamically sample the leakage signal in the receiving channel and generate a cancellation signal with the same amplitude but opposite phase of the leakage. This technique is implemented using an AD9361 transceiver chip as RF front end and a field-programmable gate array (FPGA) board as the protocol and cancellation controller. Experiments demonstrate that a suppression of around 92 to 106 dB can be achieved within 0.5 ms in a UHF RFID system. The cancellation technique is also broadband; with a matched antenna, the experiment shows that cancellation can work effectively from 0.3 to 6 GHz.

中文翻译：

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反向散射 RFID 通信的宽带和快速载波消除

超高频射频识别 (UHF RFID) 使用反向散射电磁 (EM) 调制技术在阅读器和标签之间进行通信。抑制从传输通道泄漏到接收通道的载波信号是决定阅读器灵敏度的关键因素。在这封信中，提出了一种宽带、快速的载波消除技术。阅读器系统使用两个传输端口：一个用于传输询问信号和载波（CW），另一个端口可以动态采样接收通道中的泄漏信号，并产生一个幅度相同但相位相反的抵消信号。泄漏。该技术使用 AD9361 收发器芯片作为 RF 前端和现场可编程门阵列 (FPGA) 板作为协议和消除控制器来实现。实验表明，在 UHF RFID 系统中，可以在 0.5 ms 内实现大约 92 到 106 dB 的抑制。抵消技术也是宽带；使用匹配的天线，实验表明消除可以在 0.3 至 6 GHz 范围内有效工作。