Measurements and Analysis of a Helical Antenna Printed on a Layered Dielectric Hemisphere

Radiation characteristics of a helical wire that is printed on the surface of a dielectric hemisphere have been studied theoretically and experimentally. Rigorous analyses have been performed using the method of moments (MoM). As expected, the dielectric hemisphere reduces the antenna´s operating frequency and bandwidth. Furthermore, it has improved the 3 dB circular polarization beamwidth considerably. Hemispherical structures that consist of one, or two, dielectric layers have been considered. The experimental and computed results are in close agreement with each other.