Helical antenna over different ground planes

Axial mode helical antennas have been used in satellite communication for a long time offering the advantage of a high gain in axial direction over a wide range of frequencies [1]. The concept of this antenna was established by Kraus [1], who also developed empirical rules for its design. It is well known that we can enhance the power gain in helical antenna by increasing the number of helical turns, properly choosing the helical circumference. This method, however, forces us to expand the antenna length and decreases the width of the beam unreasonably.