Antennas for cellular radio systems

The performance and feasibility of switched multibeam array antennas in cellular systems is investigated. We assume that multicarrier power amplifiers (MCPAs) are used in the base-station, to co-amplify the transmitted signals. The MCPA generates intermodulation distortion and it is shown how the multibeam antenna makes the radiated intermodulation distortion dependent on the azimuthal look-direction. Given the carrier to intermodulation distortion ratio of the MCPA, semi-analytical expression for the outage probability for the mobiles is derived assuming a log-normal fading radio channel. Furthermore, the impact of the frequency reuse factor, trunkpool scheme and number of antennas is investigated. The analysis show that when the number of antennas are increased, it is possible to reduce the requirements on the MCPA linearity