A Comprehensive Method for Quadrifilar Helix Antenna Miniaturization

ABSTRACT A compact, miniatueized, wideband quadrifilar helix antenna (QHA) is presented in this article. The proposed QHA offers the dual benefit of a substantially reduced axial length over existing miniaturized designs and a reasonable operating bandwidth. First, by loading the hollow dielectric rod, folding the arms, employing different‐width arms, and introducing a gap in the arms to realize antenna miniaturization. Second, adjusting the width and height of the gap to broad the impedance bandwidth. Moreover, a compact two‐stage Wilkinson power divider is designed, which achieves sequential phase excitation of , and for the helical arms by incorporating and phase delay lines in the transmission path. Finally, a compact and reasonable wideband QHA is simulated and fabricated. The measured results agree well with simulation. It is miniaturized ( axial height) and wide impendance bandwidth (FBW=16%). Additionally, it exhibits a peak realized gain of 5.38 dB and excellent circularly polarized performance.