This is not an question to which I can offer a definitive answer, because it depends on the cell phone system and RFID technology being used, which can vary from country to country and user to user. But generally speaking, the answer is that RFID will not significantly interfere with smartphones. Governments regulate the use of the radio spectrum to avoid having different devices interfere with one another. The main frequencies used by RFID are 125 kHz, 134 kHz, 13.56 MHz, 860 to 960 MHz and 2.45 GHz.
Some older cell phone systems operated at 869 to 894 MHz in the United States, but ultrahigh-frequency (UHF) RFID systems in this country operated from 902 to 926 MHz. Currently, PCS operates at 1,850 to 1,910 MHz and 1,930 to 1,990 MHz; 3G operates at 1,710 to 1,755 MHz and 2,110 to 2,155; and 4G operates at 2,496 to 2,690 MHz. These bands are much higher than those used by most RFID systems, so there should be very little interference.
—Mark Roberti, Founder and Editor, RFID Journal
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