Calibration of antenna efficiency in the mode switching chamber

Purpose and goal

The goal of the project was to develop a method for measuring antenna efficiency in a reverberation chamber (RC). A method, with associated measurement uncertainty, is developed. Also software for RC control and calculation of results are developed. The frequency range is decreased to 1-18 GHz, but with suggested improvements for increasing the range to that originally planned. Publication of the method is planned after a final check of a single entry in the measurement uncertainty calculation.

Expected results and effects

The results shows that measurements in a reverberation chamber (RC) obtains the antenna efficiency in an easy and accurate way. This makes that the current methods, in a fully anechoic chamber, can be simplified without affecting accuracy negatively. The simplified method not only decreases measurement cost, but also increases availability due to the fact that a RC is cheaper than a fully anechoic chamber.

Planned approach and implementation

The measurement is conducted by first measuring how power transfers between a transmitting and a reference antenna, obtaining the chamber transfer function. Thereafter the test antenna is connected and the measurement repeated. The following calculations gives the wanted efficiency since the ref. antenna efficiency is known. This method is readily applicable giving rather few restrictions on the equipment used, and yields a measurement uncertainty of about 1 dB.