Tool 05

Antenna Far-field Measurement

Check Fraunhofer distance, allowable AUT size, and measurement-distance margin for far-field antenna testing.

Parameters

Choose whether to calculate the required far-field distance from AUT size, or the maximum AUT size from available measurement distance.

Frequency
Maximum AUT Size D
Advanced Settings
Criterion Factor K
×D²/λ

The common Fraunhofer condition is R ≥ 2D²/λ, so the default value is 2.

Sweep Graph

Custom Data Step applies to Linear X scale; Log X uses automatic logarithmic points.

Required Distance [λ]

2,225.300 λ

Wavelength

29.979 mm

X Axis
Y Axis

Reference Values

Frequency [GHz]
10.000
AUT Size
1.000 m
Wavelength
29.979 mm
Criterion Factor K
2.000

Formulas

Wavelength

Calculate free-space wavelength from frequency.

λ=cf\lambda = \frac{c}{f}

Far-field Distance

Fraunhofer far-field condition distance for AUT maximum dimension D.

Rff=KD2λR_{ff} = K\frac{D^2}{\lambda}

Max AUT Size

Calculate the maximum AUT size that satisfies the far-field condition at a given measurement distance.

Dmax=RλKD_{max} = \sqrt{\frac{R\lambda}{K}}

The default K=2 corresponds to the common Fraunhofer condition R ≥ 2D²/λ.