Date Added: Jun 2009
Conventional antenna radiation efficiency measurement techniques, such as the Wheeler cap, are generally narrowband and, thus, well suited for resonant antennas. In this paper, the Johnston - Geissler (J - G) method based on the Wheeler cap principle is used in a wide frequency range. First, a good agreement between measurement and simulation in an ultra-wide frequency band is shown on a straight wire monopole antenna with different attenuators emulating antenna losses. Then, this technique is used to measure the radiation efficiency of several Ultra-WideBand (UWB) antennas.