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Chameleon Knowledge Base · The Complete Online HF Antenna Handbook

Near Field vs. Far Field

The near field is the region close enough that stored electric and magnetic energy and geometry-dependent coupling remain important; the far field is where the radiated wave has a stable angular pattern and E/H relationship.

Advanced Antenna Theory Electromagnetic Theory Reviewed 2026-07-14
The useful model: The near field is the region close enough that stored electric and magnetic energy and geometry-dependent coupling remain important; the far field is where the radiated wave has a stable angular pattern and E/H relationship.

What controls the result

The boundary is not one universal distance. Antenna size, wavelength, reactive versus radiating near-field definitions, and measurement purpose determine the appropriate criterion.

The misleading shortcut

Applying the simple far-field formula to a tiny antenna—or treating everything inside one wavelength as equally hazardous or non-radiating—oversimplifies the physics.

Make the better decision

State the antenna’s largest dimension and frequency, select the correct boundary definition, keep people and conductors outside documented clearances, and make pattern/gain measurements only at a valid distance.

Evidence boundary

Propagation and antenna metrics are meaningful only with their frequency, path, geometry, reference plane, loss assumptions, and measurement method. Use current observations and the exact installed system.

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