Optimal design of smart antenna systems for handheld devices

摘要

The design of smart antenna system for handheld devices has been a challenge for years. In this study, an attempt is made to try to solve this challenge by applying an optimal design method for the antenna arrays introduced previously. The method is based on the optimisation of the power transmission efficiency between two antennas. During the optimisation, the smart antenna array to be designed is used as transmitting antenna, and a testing antenna is introduced as receiving antenna, positioned in the far-field region. The maximum (minimum) possible radiation may then be achieved in the direction of the testing antenna if the power transmission efficiency is maximised (minimised). A compact low-profile smart antenna system has been designed using the method, which works at GSM-900 and PCS-1900 band and employs four identical inverted-F antennas as radiating elements. The dimension of the whole system is 140 mm × 80 mm × 7 mm, suitable for the application in handheld devices or other customer-premises equipment.