Planar Reconfigurable Antennas Using Circularly Polarized Metalines

First, four N-type straight metalines, each radiating a circularly polarized wave, are arrayed in the shape of a cross, where one metaline is activated and the remaining metalines are nonactivated. This antenna system is designated as the initial cross metaline antenna system (xMeTLNA system). By changing the activated metaline, the radiation beam can be steered in the azimuth direction. It is found that the radiation beam is almost omnidirectional around the antenna system axis, with a deviation of approximately 1.2 dB and a gain of 3.9 dBi. Second, a reduction in the antenna area for the xMeTLNA system is performed by bending the four N-type straight metalines. Effects of the bent metalines are small, as desired: The gain for this bent metaline antenna system is close to that for the initial xMeTLNA system, while the voltage standing-wave ratio (VSWR) remains almost unchanged.