A new method to measure radiation efficiency of terminal antennas

Abstract

This paper considers characterization of small antennas, which operate in a multipath environment, such as antennas for mobile phones and Bluetooth modules. The characterization method is based on measurements in a reverberation chamber, which is possible due to the fact that the terminals are located in a complex multipath environment, so that normal characteristics such as radiation pattern shapes are often not important. The reverberation chamber, also called a mode-stirred chamber, is known in the EMC area, and is a kind of statistic multimode chamber. The present paper reports measurements of a simple test case in an existing reverberation chamber. The test case is a dipole located at different distances from a lossy dielectric cylinder, representing human tissue. The measurements were taken in the 900 MHz-band (870-970 MHz).