Differentially-driven circularly-polarized planar aperture antenna for millimeter-wave application

This paper presents a novel differentially-driven planar aperture antenna for circularly-polarized (CP) radiation. The proposed antenna is simple in structure and is constructed on only a single layer laminate using standard printed-circuit-board (PCB) technology. Circular polarization is realized by rotationally-symmetric windmill-shaped aperture-strip formation with travelling wave distribution. An opening-cavity that is formed by metalized vias is adopted to offer favorable unidirectional radiation and higher gain. Simulation results of a prototype working at V-band show a 3-dB axial ratio (AR) bandwidth of 17.4% (56.8-67.5 GHz), which is within its -10-dB impedance bandwidth. Meanwhile, the left-handed CP (LHCP) gain is stable throughout the operating bandwidth with a peak gain of 14.2 dBi. The proposed antenna is a promising candidate for millimeter-wave (mmWave) bands due to its merits of wideband, high gain, simple structure, low cost, and easy integration with differential circuits.