RF Cafe - Near-Field / Far-Field Transition Distance

Near-Field / Far-Field Transition Distance

An article in the October 2005 edition of Evaluation Engineering entitled, "The World of the Near Field" presented formulas for three regions of the near-field that relate the largest physical dimension of the radiator to the operational wavelength.

Electrically Small Antenna Reactive Near Field

Electrically Large Antenna Reactive Near Field

Electrically Large Antenna Radiating Near Field

Variables can only be entered into colored cells.
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Some familiar frequencies to check out:
AM = 530-1710 kHz	GPS = 1575.42 MHz	PCS = 1850-1990 MHz
FM = 88-108 MHz	802.11b/g = 2.40-2.48 MHz	DBS = 12.8-14.5 MHz
ISM = 902-928 MHz	802.11a = 5.15-5.82 MHz	RFID = 13.56 MHz