A Millimeter-Wave Circularly Polarized Curl Antenna and Array

In this paper, a wideband circularly polarized curl antenna and its triangular array are proposed for millimeter-wave applications. Circularly polarized radiation is achieved by coaxial cable fed radiating curl. A parasitic stub is introduced to adjust the impedance matching and axial ratio bandwidth. Simulated impedance and axial ratio bandwidths of the element are 32.4% and 13.9%, respectively. A 2 × 2 sequential rotation triangular array shows good performances of wide impedance and AR bandwidth of 34.5% with total efficiency higher than 80%.