Circularly-polarized periodic leaky-wave antenna at millimeter-wave frequencies

A periodic leaky-wave antenna with circular polarization at millimeter-wave frequencies is presented. The antenna is designed on a planar Goubau line to have a low profile and a high efficiency. The radiating elements of the array perturb the fundamental mode of the planar Goubau line to excite a space harmonic that radiates in the desired direction. The circular polarization is obtained by inserting two dipoles on each radiating element. By suitably designing the position of the dipoles, a low axial ratio may be achieved. Results of an 8-element antenna at 40GHz are shown in this contribution.