Preliminary studies on the coupled antennas and feedlines using natural boundary conditions

In this paper, the coupling mechanism between antennas and feedlines are conceptually studied by analyzing the respective natural boundary condition of the antenna and the feedline. Different cases of the coupling between typical antennas and feedlines are discussed, analyzed and compared. When the natural boundary conditions of the antennas and the feedlines are less matched, the coupled antenna-feedline systems tend to exhibit more notable unbalanced effects. Preliminary simulated and experimental results are presented to validate the theoretic results. Finally, two remarks are drawn and expected to provide possible design guidelines in future novel antenna developments.