Dual-Loop Antennas With a Branched Feed-Line for Broadband Circular Polarisation

Abstract

Using the method of moments, we first analyse reference and present dual-loop antennas with a perturbation segment and branched feedline, respectively. The loop elements of each antenna are gradually rotated for an increased 3 dB axial ratio bandwidth. Analysis reveals that as the loop rotation angle increases, the bandwidths of the reference and present antennas reach 20% and 43%, respectively, twice and three times as broad as those of the corresponding antennas without the rotation. Next, we modify the present antenna using a sequential rotation technique and discuss the radiation characteristics. The simulated results are verified with experimental ones.