(A) study on the performance evaluation of MIMO antenna system in a reverberation chamber and some applications of microwave measurements

Abstract

In recent mobile communications environments, multipath fading phenomena that are occurred by multiple reflections and the movement of a receiver degrades the quality of mobile communication services and limits the maximum data transfer rate. In a 4th Generation mobile communication system, a MIMO scheme and an OFDM methodology are being considered as the breakthrough technology for satisfying the demand of higher quality mobile communication services without the use of additional radio resources in multipath environments. Basically, the performance of a radiating element in a mobile handset, return loss, radiation patterns, and antenna gains have been measured in an anechoic chamber. For evaluating of the performance of a MIMO handset antenna array, parameters such as mutual coupling, envelope correlation, and mean effective gain (MEG), which can be obtained from scattering parameters and radiation patterns in an anechoic chamber, have been widely utilized. Also, the channel capacity and channel correlation have been analyzed under situations when MIMO handset antenna arrays are in real communication environments such as a picocell, urban microcell/macrocell, or rural/suburban macrocell. However, the evaluation method in real communications environments is a time-consuming job because the propagation channel is varied according to the observation time. In addition, it is hard to reproduce the same fading situation when the evaluations are performed. Though the evaluation method uses a statistical approach, the parameter may be inconsistent with the same Antenna Under Test (AUT). As a result, the evaluation method by using a reverberation chamber have been introduced. Conventionally, a reverberation chamber have been widely used in Electromagnetic Compatibility and Electromagnetic Interference testings as an alternative test site of Open Area Test Sites, anechoic chambers, or transverse electromagnetic cells. The field distribution of a reverberation chamb...