Radiation mechanism of dielectric-rod and Yagi aerials

In order to give a better insight into the radiation mechanism of dielectric-rod and Yagi aerials the problem of the radiation from the free end of a semi-infinite dielectric rod or Yagi transmission line is investigated both theoretically and experimentally. Simple approximate formulas are given for the radiation pattern, the gain, the effective aperture and the beamwidth. Using a digital computer, the field near the free end is calculated and compared with the measured field distribution.