Adaptive base station antennas with additional switching element for SDMA systems

This paper proposes a new adaptive base-station antenna configuration employing an additional switching element that reduces that influence of grating lobes caused by wide inter-element spacing. The influence of fading, the angle spread of incoming waves, and inter-element spacing of the array on the proposed antenna performance is investigated by computer simulation. The output signal-to-interference and noise ratio (SINR) of the proposed antenna compared to the conventional adaptive antenna employing an equilateral triangular array shows a maximum 5-dB improvement when applying the proposed antenna to two-user space division multiple access (SDMA) systems.