# PesWiki.com

## Antenna Measurements

Lasted edited by Andrew Munsey, updated on June 15, 2016 at 2:04 am.

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Antenna measurement techniques refers to the art of testing Antennas to ensure that the antenna meets specifications.

#### Description

Parameters of antennas commonly of interest are There was an error working with the wiki: Code[3], There was an error working with the wiki: Code[4], There was an error working with the wiki: Code[5], There was an error working with the wiki: Code[6], and There was an error working with the wiki: Code[7]. The antenna pattern is the response of the antenna to a plane wave incident from a given direction or the relative power density of the wave transmitted by the antenna in a given direction. For a reciprocal antenna, these two patterns are identical. A multitude of antenna pattern measurement techniques have been developed. The first technique developed was the far-field range, where the antenna under test (AUT) is placed in the far-field of a range antenna. Due to the size required to create a far-field range for large antennas, near-field techniques were developed, which allow the measurement of the field on a surface close to the antenna (3-10 wavelengths typically). This measurement is then transformed to the far-field (infinity). A third common method is the compact range, which uses a reflector to create a field near the AUT that looks approximately like a plane-wave.

#### Far-Field Range

The far-field range was the original antenna measurement technique, and consists of a placing the AUT a long distance away from the range antenna. Generally, the far-field distance, d, is considered to be

:d = There was an error working with the wiki: Code[1],

where D is the antenna diameter and {\lambda} is the wavelength of the radio wave. Separating the AUT and range antenna by this distance reduces the phase variation across the AUT small enough to obtain a reasonable antenna pattern.

#### Planar Near-Field Range

Planar near-field measurements are conducted by scanning a small probe antenna over a planar surface. These measurements are then transformed to the far-field by use of a There was an error working with the wiki: Code[8].

#### Spherical Near-Field Range

Spherical near-field ranges measure the electric field on a spherical surface close to the AUT. Spherical harmonics are used transform these measurements to the far-field.

#### Cylindrical Near-Field Range

Cylindrical near-field ranges measure the electric field on a cylindrical surface close to the AUT. Cylindrical harmonics are used transform these measurements to the far-field.

#### Related articles

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AMTA

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