A Wideband Low-Profile Millimeter-Wave Circularly Polarized Array Using Asymmetric Aperture Radiating Element

This letter presents a novel substrate-integrated asymmetric aperture radiating element with circularly polarized (CP) radiation. The proposed CP radiating element is constructed using only a single layer laminate via standard printed circuit board (PCB) technology; thus, it is simple in structure yet can achieve high gain and wide bandwidth. Circular polarization is realized by SIW septum constructed by metalized vias which introduce 90° phase difference and orthogonal electric fields simultaneously. A prototype of 1 × 4 array using the proposed CP radiating element is constructed, fabricated and measured, and the measurement results indicate that a −10 dB impedance bandwidth of 20.1% (29.6 GHz to 36.2 GHz) and a 3 dB axial ratio bandwidth of 29.3%(26.2 GHz to 35.2 GHz) have been achieved. Meanwhile, the left-hand CP (LHCP) realized gain is stable throughout the operating bandwidth with a peak value of 12.2 dBic. The proposed antenna can be a promising candidate for various consumer-level millimeter-wave (mm-Wave) band applications due to its merits of wideband, high gain, low cost, compact size, and easy integration with front-end circuits.