Tool 04

Antenna Near-field Measurement

Plan near-field scan size, sampling interval, probe spacing, and measurement grid requirements for antenna measurement setups.

Parameters

Enter a reference frequency, AUT or scan size, measurement distance, and maximum measurement angle. Set the graph sweep range separately below.

Reference Frequency

AUT Width

AUT Height

Measurement Distance z

λref

Maximum Measurement Angle

deg

Advanced Settings

Sampling Factor

×λref

The default sample spacing is λref/2.

Sweep Graph

Measurement distance z uses each frequency point's wavelength basis: 5.000λ(f).

Data Step (blank = Auto)

GHz

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

Result cards and reference values use the current Reference Frequency = 10.000 GHz. The frequency sweep graph uses the independent range set in the sweep controls.

X AxisY Axis

Reference Values

λref: 29.979 mm
Measurement z: 149.896 mm
X Points: 103
Y Points: 103
Available AUT: (1.081 × 0.881) m

Formulas

Reference Wavelength

Calculate the wavelength from the reference frequency.

\lambda_{ref} = \frac{c}{f_{ref}}

Sample Spacing

Planar near-field sample spacing. The default is λref/2.

\Delta = k\lambda_{ref}

Measurement Distance

Reference calculations convert distance to a λref multiple; frequency sweeps convert each point to its wavelength multiple.

z = N_\lambda\lambda_{ref},\quad z(f)=N_\lambda\lambda(f)

Scan Area

Add the margin from measurement distance and target angle to the AUT size.

L_{scan} = D_{AUT} + 2z\tan(\theta_{max})

Point Count

Divide scan area by sample spacing to calculate the required point count.

N = \left\lceil \frac{L_{scan}}{\Delta} \right\rceil + 1

Max AUT Size Inversion

Maximum AUT size that can satisfy the target angle within the given scan area.

D_{AUT,max} = L_{scan} - 2z\tan(\theta_{max})

This model is a first-order estimate based on planar near-field scan truncation and λ/2 sampling at the selected reference or sweep frequency.