Single-layer differentially-fed circularly polarized aperture antenna for 60 GHz applications

This paper presents a new differentially-fed 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. The antenna is fed using substrate integrated waveguide (SIW), which features low transmission loss and high efficiency. Circular polarization is realized using a dual loop-like strips formation with travelling wave distribution as the radiating element. A cavity that is formed by the SIW metalized vias is adopted to offer favorable unidirectional radiation and higher gain. Measurement results of the antenna show a 3-dB axial ratio (AR) bandwidth of 16.3% (56.5-66.5 GHz), which is within its -10-dB impedance bandwidth. Meanwhile, the right-handed CP (RHCP) gain is stable throughout the operating bandwidth with a peak gain of 12.4 dBi. The proposed antenna is a promising candidate for 60 GHz applications due to its merits of wideband, high efficiency, simple structure, low cost, and easy integration with differential circuits.