Power Cable Antenna Problem in UHF RFID IoT Devices: Causes, Consequences, and Solutions for FM-50x and ESP32


What are the best practices to avoid unwanted UHF RFID tag readings caused by the power cable acting as an antenna in IoT devices using FM-50x modules and ESP32 microcontrollers?

This question is more concise and specific, and it uses appropriate technical terms for the domain of IoT and RFID. It also indicates the type of device, module, and microcontroller that are involved in the problem.


UHF RFID is a technology that enables the identification and tracking of objects using radio waves. UHF RFID tags are small, passive devices that can be attached to various items and store information such as ID, serial number, or other data. UHF RFID readers are devices that can communicate with the tags and read or write data to them.

One of the challenges of using UHF RFID in IoT devices is the interference caused by the power cable that supplies the device. The power cable can act as an antenna and pick up the UHF RFID signals from nearby tags, resulting in unwanted tag readings. This can affect the accuracy and reliability of the IoT device and its applications.

There are several ways to mitigate this problem and improve the performance of the UHF RFID system. Some of the best practices are:

  • Use a shielded power cable. A shielded power cable has a metal layer that covers the inner wires and blocks the electromagnetic interference from the outside. This can prevent the power cable from acting as an antenna and reduce the unwanted tag readings. Shielded power cables are widely available and compatible with most IoT devices and power sources.
  • Use a ferrite bead. A ferrite bead is a small, cylindrical component that can be attached to the power cable near the IoT device. A ferrite bead acts as a filter that blocks the high-frequency signals and allows the low-frequency signals to pass through. This can reduce the UHF RFID signals that reach the power cable and the IoT device, and improve the signal-to-noise ratio. Ferrite beads are inexpensive and easy to install.
  • Use a directional antenna. A directional antenna is an antenna that can focus the UHF RFID signals in a specific direction and reject the signals from other directions. This can increase the reading range and accuracy of the UHF RFID reader, and reduce the interference from the power cable and other sources. Directional antennas are more complex and costly than omnidirectional antennas, but they can offer better performance and flexibility for certain applications.
  • Use a tag filter. A tag filter is a software or hardware component that can filter out the unwanted tag readings based on certain criteria, such as tag ID, tag type, tag location, or tag frequency. This can eliminate the false positives and negatives caused by the power cable and other factors, and improve the data quality and integrity. Tag filters can be implemented in the IoT device, the UHF RFID reader, or the cloud server, depending on the system architecture and requirements.
  • These

are some of the best practices to avoid unwanted UHF RFID tag readings caused by the power cable acting as an antenna in IoT devices using FM-50x modules and ESP32 microcontrollers. By following these practices, one can enhance the performance and functionality of the UHF RFID system and the IoT device, and enable more efficient and effective applications.

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