EMC/EMI Near-Field Distance & Wavelength Calculator mechanism

Model scope

The wavelength formula is standard under SI units. The distance formulas are conditional engineering rules of thumb, and the honest-label warning is appropriate, but the product needs explicit SI input units, D definition, domain constraints, and unambiguous output labels before release.

• The formula λ/2π is a rule-of-thumb scale associated with reactive near-field behavior for some source types; labeling it a general far-field boundary is ambiguous and is not universally valid.
• The Fraunhofer distance 2D²/λ is a standard rule of thumb for the far-field boundary when D is the maximum physical aperture or structure dimension, but its applicability and numerical factor depend on geometry and allowable phase error.
• The specification does not define whether the two distances are separate outputs, whether one should be selected, or whether the larger distance should be treated as the conservative boundary.
• The specification does not state whether D is the maximum overall dimension, aperture diameter, cable length, or another characteristic dimension.

Units and conventions

• Frequency must be supplied in hertz (Hz).
• Antenna or structure size D must be supplied in metres (m).
• Wavelength is computed in metres using c = 299792458 m/s.
• The λ/2π distance and 2D²/λ distance are approximate rule-of-thumb values, not geometry-independent EMC limits.
• D must be a nonnegative physical length; the Fraunhofer result is unavailable when D is omitted.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "frequency_hz": 100000000,
    "D_m": 0.3
  },
  "expected_outputs": {
    "wavelength_m": 2.99792458,
    "reactive_scale_m": 0.477134516,
    "fraunhofer_boundary_m": 0.060041537
  },
  "working": "λ = c/f = 299792458 / 100000000 = 2.99792458 m. Reactive scale = λ/(2π) = 2.99792458 / 6.283185307 = 0.477134516 m. Fraunhofer boundary = 2D²/λ = 2(0.3²)/2.99792458 = 2(0.09)/2.99792458 = 0.18/2.99792458 = 0.060041537 m."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The zero-frequency vector exposes an undefined division-by-zero case that must be rejected. The unit probe also exposes a severe convention hazard: ignoring the D unit changes the Fraunhofer result by four orders of magnitude.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json