Abstract

This paper examined the radiation behaviour of Yagi-Uda antenna designs consisting of 3, 4, 5, 6, 7, 8, 9 and 11 elements. A point matching method of moment procedure was utilized as an analytical tool to obtain the current distribution on the antennas, where an excitation voltage of 1V was applied at the driven element of the antennas. This facilitated the computation of radiated far fields. Computational results for the current distribution depicted non- linearity in the amplitude and it was seen that the driven element has the highest current amplitude. However, it was found that the radiated fields due to corresponding current were propagated in an end-fire mode where the direction of propagation of the fields was in the same direction as the orientation of the antennas. It was seen that larger percentage of electromagnetic energy was focused in the main lobe with minimal side and back lobe radiations.