UHF-Band Quadrifilar Helix Antenna with Near Hemispherical Coverage for High Power Telecommand Application

This manuscript reports the development of a right hand circularly polarized (RHCP) quadrifilar helix antenna (QFHA) with near hemispherical coverage for telecommand application. It can transmit higher than 1 kW CW power in the UHF-band continuously for more than 1.5 hr. The antenna yields an impedance bandwidth ≥ 35.3%. It reveals a gain of ≥3.5 dBic with half-power beamwidth ≥145°. The cross polar discrimination (XPD) is better than 20 dB. The antenna demonstrates improved features and measured results are enhanced compared to the earlier reported investigations.