Circularly polarized open loop antenna backed by square AMC with different feeding mechanisms

Two circularly polarized open loop antennas, backed by square patch AMC ground planes and operating at the GPS Li band are presented. The first one is fed by a co-planar waveguide (CPW) and the second one is fed by a vertical probe. The CPW antenna has provided measured S
₁₁
and AR bandwidths of ~11% and 6% respectively compared to ~21% and 5% for the vertical probe fed antenna. Both antennas have provided useful bore-sight gain at the desired frequency.