Millimeter-Wave Planar Wideband Circularly Polarized Antenna with End-Fire Radiation

Abstract

This paper presents a planar wideband circularly polarized (CP) antenna with end-fire radiation for millimeter-wave (mmWave) applications. The antenna is realized by the combination of an open-ended substrate integrated waveguide (SIW) line and a pair of open-ended SIW cavities. The SIW line consisting of trapezoidal notch and inductive window is used for feeding network, symmetrical notches etched on the open-ended SIW cavities are designed for generating CP end-fire radiation. Its operating mechanism is explained for easy understanding. To verify the design, a prototype is fabricated and measured, which demonstrates the reflection coefficient bandwidth of 35.3%, 3dB axial ratio (AR) bandwidth of 37.3%, front-to-back ratio (FTBR) of larger than 6.8 dB, and a peak left handed circularly polarized (LHCP) gain of 4.87 dBic. The proposed CP end-fire antenna would be an attractive candidate for mmWave wireless applications.