Rapid Small-Antenna Measurements

Abstract

We give an overview of research performed during previous years on the development ofmethodsfor measuring and determining the radiation patterns ofsmall antennas. The work has focused on developing a spherical multi-probe system for measuring the 3-D complex radiation patterns ofsmall antennas, as e.g. used in mobile terminals, without the need to move the device under test during the measurement. A demonstrator system with 32 dual-polarisedfield probes has been manufactured and evaluated. The frequency range of the measurement system covers most of the current mobile communications systems, i.e. from 800 MHz to 3 GHz. The radius of the measurement sphere is 1 m. The far field is determined with the spherical-wave expansionbased near-field to far-field transformation from the signals measured at each probe port. Since the system allows measuring a 3-D pattern within seconds, it facilitates specific research that would not be feasible with traditional measurement techniques. Some of these new results are presented. Finally, foreseen future developments ofthese measurement methods are presented.