Generalised absorption efficiency of Yagi-Uda antennas

The generalised absorption efficiency is the ratio of the all-spectrum absorbed to scattered energies. Although often estimated as 0.5, it should be rigorously calculated for the accurate estimation of fundamental limits. Many antennas, as tuned in the resonant frequency, absorb as much power as they scatter. One of the interesting properties of the Yagi-Uda antennas is more absorption rather scattering. Absorption, scattering, and extinction cross sections of a typical Yagi-Uda antenna are reported in this paper to study the generalised absorption efficiency for this antenna type.