A Bandwidth-enhanced millimeter-wave microstrip comb-line array antenna with parasitic elements on liquid crystal polymer substrate

In this paper, a microstrip comb-line array antenna with parasitic elements for bandwidth enhancement at 60 GHz band is proposed. The antenna is fabricated on liquid crystal polymer (LCP) substrate due to its low dielectric loss. The antenna consists of a waveguide-to-microstrip mode transition, 16 radiation elements which construct an one-dimensional array and a terminated element. Two side-coupled parasitic elements are set symmetrically on both sides of each radiation element and an end-coupled parasitic element is set at the edge of the element for the sake of bandwidth enhancement. The antenna can be made consistently for the emerging market in the near future. Good agreement between simulated and measured results is obtained. Around 5% impedance bandwidth for |S₁₁| less than -10 dB and 10% gain bandwidth for maximum gain over 10 dBi are finally obtained.