CR95HF天线设计问题

你好，
1）RFID阅读器的读取范围取决于阅读器天线，还取决于标签天线尺寸，调谐和标签IC协议和功耗。因此，在不知道系统的情况下很难回答它
但是，我们提供了一些工具来帮助客户设计他们的系统
 来自e-Design套件的NFC天线模块，请访问https://my.st.com/analogsimulator/flex_app/bin/eds_antenna_design.html?msg=%7B%22action%22%3A%22new_design%22%7D
 允许根据其尺寸评估天线电感STSW-95HF03：CR95HF EMI滤波器计算excel表http://www.st.com/content/st_com/en/products/embedded-software/st25-nfc-rfid-software /stsw-95hf003.html
 允许优化CR95HF调谐电路并计算读取器天线产生的场强。即使这个工具没有考虑到标签和阅读器之间的相互耦合效应，估计功率范围可能会有所帮助。带有M24L-DISCOVERY套件的CR95HF演示板具有34x47mm / 2转/ 0.5ohm ~424nH天线和NUCLEO-NFC03A1板具有a
 34x47mm / 4转/0.8ohm~1120nH天线。第一个天线示例提供高场强，这对于最大化M24LR04E-R ISO15693I²C/ NFC芯片所展示的能量收集功能的性能非常重要。具有4匝的第二天线在转弯数和阻抗方面提供了良好的折衷，以在每种协议中在读取模式下最大化性能。
这两种参考设计允许最大9 cm的读取范围，信用卡大小为ISO 15693标签，6 cm为ISO14443标签。
 
 
2）读卡器和标签天线不需要具有相同的电感。读写器天线电感通常小于标签天线阻抗。
3）多标签检测是CR95HF支持的RF协议的一部分。但是它不是由CR95HF自动管理的，它必须使用CR95HF的命令集在微控制器固件级别进行管理。
此库存过程（逐步标记UID检测）取决于标签可见性（检测量，通信期间的冲突）和协议。
最好的祝福，
NFC / RFID支持



以下为原文




Hello,
1) RFID readers read range depends on reader antenna but also on Tag antenna dimensions, tuning , and tag IC protocol and power consumption. As a consequence it is difficult to answer to predict it without knowing the system
However we provide some tools to help customers to design their system

• NFC antenna module from e-Design suite at  https://my.st.com/analogsimulator/flex_app/bin/eds_antenna_design.html?msg=%7B%22action%22%3A%22new_design%22%7D
    allows to evaluate the antenna inductance based on its dimensions
  
• the STSW-95HF03: CR95HF EMI filter calculation excel sheet at http://www.st.com/content/st_com/en/products/embedded-software/st25-nfc-rfid-software/stsw-95hf003.html
    allows to optimize the CR95HF tuning circuit and calculated the field strenght generated by the reader antenna. even if this tool doeas not take into account the mutual coupling effect between a tag and the reader, it may be helpful to estimate the powering range.
  

The CR95HF demo board delivered with the M24L-DISCOVERY kit features a 34x47mm/2 turns/0.5ohm~424nH antenna and NUCLEO-NFC03A1 board features a
34x47mm/4 turns/0.8ohm~1120nH antenna. First antenna example provides a high field strength, important to maximize the performance of Energy harvesting fonctionality demonstrated with M24LR04E-R ISO15693 I²C/NFC chip. Second antenna with 4 turns provides a good compromise in turn number and impedance to maximise performance in read mode in every protocol.

these 2 reference design allows up to 9 cm read range with credit card size ISO 15693 tags and 6 cm with ISO14443 tags.





2)  There is no need to have same inductance for reader and tag antenna. Reader antenna inductance is usually less than tags antennas impedance.

3) Multi tag detection is part of RF protocols supported by the CR95HF. However it is not managed automatically by CR95HF and It has to be manged at micro controller firmware level using the command set of CR95HF.

This inventory procedure (step by step tag UID detection) depends on tag visibility (detection volume, collision during communication) and protocol.

best regards,

NFC/RFID Support