  Large volume helicon plasma sources are of particular interest for large
scale semiconductor processing, high power plasma propulsion and recently
plasma-material interaction under fusion conditions. This work is devoted to
studying the coupling of four typical RF antennas to helicon plasma with
infinite length and diameter of $0.5$~m, and exploring its frequency dependence
in the range of $13.56-70$~MHz for coupling optimization. It is found that loop
antenna is more efficient than half helix, Boswell and Nagoya III antennas for
power absorption; radially parabolic density profile overwhelms Gaussian
density profile in terms of antenna coupling for low-density plasma, but the
superiority reverses for high-density plasma. Increasing the driving frequency
results in power absorption more near plasma edge, but the overall power
absorption increases with frequency. Perpendicular stream plots of wave
magnetic field, wave electric field and perturbed current are also presented.
This work can serve as an important reference for the experimental design of
large volume helicon plasma source with high RF power.
