A dipole aerial working in conjunction with a system of passive directors and a passive reflector is called a Yagi aerial or Yagi array or sometimes an 'end-fire parasitic aerial'. It is named after the Japanese engineer who wrote in English about the work originally published in Japanese between 1926 and 1928 by a colleague, Professor Uda. The Yagi and modified Yagi array are the most popular of all aerials used for the reception of television signals. Indeed, they form the basis of almost all domestic vhf and uhf aerials. Although one could add directors almost indefinitely to a
Yagi aerial, in practice the more directors that are added, the progressively smaller becomes their effect on gain and directivity. After about nine or so directors, not much benefit is derived by adding more. A better idea then to secure enhanced gain and directivity is to couple two, four or more complete Yagi aerials together. This technique produces so-called stacked or broadside arrays, the individual arrays being placed one above the other or side by side respectively. Research Yagi Aerial
Abbreviations
Research Yagi Aerial
