Radio Spectrum
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That portion of the electromagnetic spectrum for which electromagnetic waves can be propagated through Earth's atmosphere or oceans using alternating current and an antenna. This is defined as 3Hz to300 GHZ, which includes the electric, radio, and microwave areas of my graph.
- The three lowest bands, ELF, SLF and ULF, are used for undersea rather than atmospheric transmission, and are often excluded from the radio spectrum. I have italicized these bands in the chart below.
- The two highest bands, SHF and EHF, are often treated as a separate microwave band, which is sometimes extended to the far-infrared boundary at 3,000GHz.
- Between 300GHz and the infrared-visible range the Earth's atmosphere is effectively opaque to EM waves.
- The use of the radio spectrum is governed nationally, which has lead to problems and compromises in creating an international RFID standard. (Why couldn't the radio pioneers» at the turn of the last century foresee the need for global standards today?
) - RFID operates in unlicensed portions of the radio spectrum known as the Industrial, Scientific and Medical (ISM) bands.
| Abbr. | Band Description | Frequency (F) | Wavelength (λ) |  US Frequency Allocation» |
| ELF | Extremely Low Frequency | 3 – 30 Hz | 100,000 – 10,000 km | |
| SLF | Super Low Frequency | 30 – 300 Hz | 10,000 – 1000 km | Undersea» |
| ULF | Ultra Low Frequency | 300 Hz – 3 kHz | 1000 – 100 km | |
| VLF | Very Low Frequency | 3 – 30 kHz | 100 – 10 km | |
| LF | Low Frequency | 30 – 300 kHz | 10 – 1 km | RFID: 125 - 134 kHz |
| MF | Medium Frequency | 300 kHz –3 MHz | 1 km – 100 m | AM Radio: 535 kHz - 1.605 MHz |
| HF | High Frequency | 3 – 30 MHz | 100 – 10 m | RFID: 13.56 MHz |
| VHF | Very High Frequency | 30 – 300 MHz | 10 – 1 m | TV Channels 2-6: 54 - 88 MHz FM Radio: 88 - 108 MHz TV Channels 7-13: 174 - 216MHz |
| UHF | Ultra High Frequency | 300 MHz – 3 GHz | 1 m – 100 mm | TV Channels 14-69: 512 - 806 MHz Cell Phone: 850 MHz RFID: 860 - 960 MHz Cell Phone: 1.9 GHz WiFi (802.11): 2.4 - 2.4835 GHz RFID: 2.45 GHz |
| SHF | Super High Frequency (Microwave) | 3 – 30 GHz | 100 – 10 mm | RFID: 5.8 GHz |
| EHF | Extremely High Frequency (Microwave) | 30 – 300 GHz | 10 mm – 1 mm | |
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