A simple design for circularly polarized ring‐slot antennas

A simple method for generating circular polarization (CP) radiation from an annular‐ring slot antenna is described in this paper.The slot antenna is excited by an L‐shaped coupling strip loaded with a resistor. The lengths of the two arms of the coupling strip are the same, and when they are equal to the outer radius of the ring slot, good CP radiation can be directly obtained. Moreover, the resistance value of the loading resistor is insensitive to the axial ratio of the CP antenna. Several prototypes are fabricated, and the measured and simulated results confirm the validity of the propose design. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2262–2265, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26285