Trapped wave antennas

The question is first raised as to how a 'trapped' wave radiates, and what beam shapes it can produce. The results are compared with the radiation fields produced by conventional antenna apertures. A flush-mounted type of antenna is discussed which utilizes waves trapped in single and multiple dielectric layers. The calculated mode characteristics are in very good agreement with experimental results. By means of phase and amplitude control, it should be possible to design such antennas with a great variety of beam shapes in azimuth and elevation.