Probe-corrected spherical near-field antenna measurements

Double -Step -Scanning Technique for Spherical Near-Field Antenna Measurements

Probe-corrected spherical near-field antenna measurements with an arbitrary probe set certain requirements on an applicable scanning technique. The computational complexity of the general high-order probe correction technique for an arbitrary probe, that is based on the scanning, is , where is proportional to the radius of the antenna under test (AUT) minimum sphere in wavelengths. With the pre...

Cylindrical/Spherical Near-Field Antenna Measurement System

A low-cost, fully operational cylindrical and spherical near-field antenna measurement system designed, built, and programmed by a University of Rhode Island Capstone team is presented. The goal of this project was to modify an existing planar near-field system and apply new processing techniques to extract the far-field patterns of an antenna under test (AUT) of any physical shape. The aim of ...

Advanced Spherical Antenna Measurements

General Analytic Correction for Probe-Position Errors in Spherical Near-Field Measurements

A general theoretical procedure is presented to remove known probe-position errors in spherical near-field data to obtain highly accurate far fields. We represent the measured data as a Taylor series in terms of the displacement errors and the ideal spectrum of the antenna. This representation is then assumed to be an actual near field on a regularly spaced error-free spherical grid. The ideal ...

Optical antenna: Towards a unity efficiency near-field optical probe

We demonstrate that an antenna can be used to realize a near-field optical probe that combines spatial resolution well below the diffraction limit with transmission efficiency approaching unity. The probe consists of a planar bow-tie antenna with an open-circuited gap at its apex. We present proof-of-principle measurements using microwave radiation and discuss scaling the antenna to the visible...