A Figure-of-Merit for Pattern Reconfigurable Antennas

The performance of pattern reconfigurable antennas is evaluated with the purpose of deriving a figure-of-merit for pattern reconfigurability. A general formulation is provided for the average gain achieved by a reconfigurable antenna (RA) in the presence of an incoming plane wave with statistically distributed direction-of-arrival and polarization. It has been observed that for usual scenarios, the polarization dependence can be isolated and the RA performance is directly related to the maximum realized gain achieved in each direction, averaged for all angular directions. This average gain is proposed as figure-of-merit for pattern reconfigurability and it is shown that it can be interpreted as the equivalent number of configurations with non-overlapped radiation patterns. Finally, this figure-of-merit is evaluated for several published RA's showing that it captures the intuitive notion of pattern reconfigurability, that is, the number of different patterns that the RA can produce.