The high-frequency/radio-frequency cards (tags) are widely used, such as financial payment, access management, product traceability, workshop positioning, inspection records, etc.
These HF type cards mainly work in the 13.56MHz frequency band and include multiple protocols, such as 15693, 14443A\B, etc.
The RF performance and protocol conformance testing are quite important parts in the design and production process of HF/UHF cards and readers.
We used Xilinx’s FPGA to implement a low-cost RFID characteristic tester, and completed the corresponding C# host computer software.
The parameters are as follows:
① Spartan 3E-1200K main controller, onboard RAM and ROM.
② The highest rate of the UART interface is up to 1.5Mbps, which is used for PC communication.
③ 0-30MHz arbitrary waveform generator, built-in 165Msps 12bit DA converter, which can provide the voltage range of 50mVp-p to 10Vp-p between the frequency of 0-15MHz.
④ The 100MH bandwidth 12bit AD converter can perform low-pass and band-pass sampling.
⑤ Used for 13.56MHz ISO15693, ISO14443 and other high-frequency RFID transceiver test, signal modulation and demodulation analysis, and carrier generation.
⑥ It can be used for the processing and analysis of 915MHz baseband signals or down-conversion signals.
The design of the tester is very complex, and even includes frequency analysis, modulation analysis, protocol analysis, etc. at higher frequencies.
Based on this equipment, we have developed another very high-end RFID test board, using the 14-layer microwave Rogers PCB and Xilinx SOC chip ZYNQ, which contains ARM A9 processors and a powerful FPGA. It supports the QAM modulation and demodulation with frequencies up to 2.4GHz carrier. Besides, we also designed a circular polarization cut-angle microstrip antenna for 915MHz.
FPGA module framework for VHDL design.
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