Split-beam mode four-arm slot sinuous antenna

A coplanar waveguide (CPW) center-fed four-arm slot sinuous antenna is introduced in this letter. The antenna demonstrates broadband characteristics in terms of its split-beam radiation pattern and angle of maximum gain as well as multiband characteristics in terms of axial ratio (AR), omnidirectionality, polarization, and return loss. It is observed experimentally and computationally that regions of low AR with alternating polarization handedness, good omnidirectionality, low return loss, and high antenna gain/efficiency appear in narrow frequency bands. Measured and simulated results are presented to discuss the principles behind the antenna operation and venues for future performance optimization.