Umudike Journal of Engineering and Technology

The broadband features of Yagi-Uda antenna are investigated in this paper. Upon applying method of moments, an integral equation that describes the electromagnetic behaviour of Yagi-Uda antenna in an impressed field, is transformed into matrix equation, and solution of which is the excitation current on the antenna. The far zone electric field is determined by introducing the known excitation current in the far field integral expression. It is found that the distribution of the current, far zone electric field patterns, half- power beam- width including front-to-back ratio are relatively stable over a considerable frequency range of interest. Furthermore, it is however found that the beam widths of the electric field patterns measured at 0.707 points of main axial lobe radiations reduce as the number of elements in the array increases while the front- to- back ratio exhibits lowest value when the number of elements is fourteen, after which front-to-back ratio increases with increase in the number of elements in the array. In the realization of all the computed results presented in this paper, feed point voltage of unit volt is applied at the antenna geometry.