Investigation into Imperfection of Phase Shifter for Smart Antenna Implementation

The success of a smart antenna system is indicated by the accuracy of pointing its main beam to the desired direction while directing its nulls´ locations to the interference signals. Beside the effective algorithm chosen to be the beamforming algorithm, the precision of phase shifters employed to adjust the phase of the received/transmitted signals is also important. The phase shifters available on the market indicate some phase shifting error as appeared in their data sheets. Therefore, this paper investigates into the effect of imperfect phase shifters on the beamforming performance and Signal-to- Interference Ratio of the system. This information is considered to be useful for the smart antenna designers so that they can set an addition margin to achieve the designated Signal-to- Interference Ratio when utilizing imperfect phase shifters.