Folded Crossed-Dipole Antenna for Circular Polarization

We present a small compact crossed-dipole antenna comprising two printed folded crossed-dipole arms and a pair of vacant quarter printed rings to generate circular polarization (CP). The design of a compact, small-sized CP antenna is realized by rotating the arms of a conventional crossed dipole and then folding the rotated arms twice into a figure-eight-like structure. By undertaking these rotation and folding techniques, we achieve a miniaturized CP crosseddipole antenna that performs satisfactorily. The compact crossed-dipole folded antenna with overall dimensions of 22.3 mm×39.9 mm×0.508 mm $(0.22 \lambda_{0} \times 0.39 \lambda_{0} \times 0.0052 \lambda_{0}$ at 3.07. GHz) has a measured $|S_{11}| \lt - 10 \mathrm{dB}$ impedance bandwidth of 2.81-3.51 GHz (22.15%) and a simulated 3-dB axial bandwidth of 2.85-3.30 GHz (14.63%).