Two methods for estimating the diversity characteristics of built-in antennas for mobile communication equipment

In mobile communications, the diversity technique plays a very important role in improving the quality of digital transmissions, and the fading simulator is widely employed to achieve a quasi-fading environment. However, the fading simulator cannot be used to evaluate the effects of the antenna radiation patterns on the diversity characteristics. It is very difficult to predict analytically the radiation characteristics of built-in antennas in portable radio equipment, because they are affected by nearby electrical devices. Therefore, an experimental investigation is important. We proposed two measurement systems for evaluating the radiation characteristics of built-in antennas for hand-held radio equipment. Two methods for estimating the diversity characteristics of mobile communication equipment using these two measurement systems are presented.