Polarization Properties of the Helix Antenna

The mode structure and surface fields of a helix with a dielectric core have been found. Conditions for constructing an antenna with perfect circular polarization in all directions have been identified and by defining a circular polarization index (CPI) optimum antennas may be found. The CPI essentially measures the degree of satisfaction of the Rumsey-conditions, ¿ = ±jZoH¿, for the surface fields. With a price of a smaller bandwith the presenc~ of a suitable dielectric is able to improve the wide angle polarization properties of the helix antenna.