The development of anomalous responses on single tapered and untapered Yagi antennas as a function of antenna length

Recently a class of anomalous responses has been shown to occur on the untapered 7-element Yagi antenna. These anomalies are associated with resonances involving the leading director elements and the resonant frequencies are contained within a narrow frequency band immediately below the director array cutoff frequency. This work presents both theoretical and experimental results to show that this class of resonance may involve not only the leading directors but also the remaining elements on the antenna as the number of director elements is increased. It is shown that modifications to an element tapering scheme are effective in controlling these resonances and increasing the antenna bandwidth.