How close can I mount two high-frequency (HF) Mifare or ISO 14443 RFID interrogators to each other without causing them to interfere with one another?
To answer your question, I reached out to Victor Vega, the director of RFID and Near Field Communication (NFC) solutions at NXP Semiconductors, the company that manufactures Mifare chips, as well as many other chips conforming to the ISO 14443 standard. Here is Victor's response: "Generally speaking, we advise that you take the diameter of the largest antenna and have at least three times as much distance between that antenna and the closest edge of another antenna. For example, if you have two reader antennas that are 10 centimeters [3.9 inches] in diameter, then you need at least 30 centimeters [11.8 inches] between the closest edges of the antennas."
—Mark Roberti, Founder and Editor, RFID Journal
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