Dual‐Band Circularly Polarized Helix Antenna With Conical Radiation Pattern for Global Navigation Satellite Systems Application

ABSTRACT A circularly polarized (CP) helix antenna with conical radiation pattern operating in Global Positioning System L5 (1.176 GHz) and L1 (1.575 GHz) bands is proposed. Adopting helix arm nesting technique, the proposed antenna is equipped with two tapered helix radiation arms, namely, outer tapered helix arm and inner tapered helix arm, which are operated in L5 and L1 bands, respectively. Two ports are designed to excite the two tapered helix arms. The antenna can operate at L5 and L1 bands with right‐hand circular polarization (RHCP) conical radiation pattern. A prototype of the antenna is fabricated and tested. The results show that the measured VWSRs of L5 and L1 bands are superior to 1.2/1.1, respectively. The measured port isolation values at two bands are lower than −25 dB. The conical radiation patterns with peak gain direction (PGD) of about ±28° for both bands are achieved. What's more, more than 8.0 dBi peak gain and < 3 dB axial ratio (AR) in PGD for both bands are achieved. The proposed antenna is promisingly useful for application on satellite Global Navigation Satellite Systems (GNSS).