Low‐Profile Helical Antenna Array

This chapter explains a low‐profile high‐gain helical antenna array for satellite communications, using the method of moments (MoM) and rotational vector method. Each helical antenna acts as an array element, having a vertical probe, which protrudes into a thin circular cavity. The vertical probe is excited by an electromagnetic (EM) wave traveling in the circular cavity, that is, the helical element absorbs the EM wave power inside the cavity through the vertical probe and radiates a circularly polarized (CP) wave into free space. The chapter discusses controlling of the excitation amplitude and phase of each helical element. The helical antenna is specified by the parameters such as, diameter of the conducting circular ground plane D
_GP
, diameter of the helical arm 2r
_helix
, pitch angle α, number of helical turns N, wire diameter of the helical arm 2a, starting height of the helical arm above the ground plane h, and antenna height H.