Metamaterial-line based feed-networks for wideband circularly polarized antennas

This paper presents a number of metamaterial-line based feed-networks for wideband circularly polarized (CP) antennas. These feed-networks were designed and fabricated using lumped-element integrated microstrip transmission-lines that were synthesized by using metamaterial transmission-line concept. Design examples for dual-fed, triple-fed and four-element CP antennas are demonstrated. Excellent performance and reduced substrate sizes were achieved.