Circularly polarized slotted substrate integrated waveguide array with low axial ratio over wide angles

A circularly polarized slotted substrate integrated waveguide (SIW) array antenna is presented. This array is based on a new type of circularly polarized (CP) slot radiator presenting good circular polarization performances for left-hand and right-hand circular polarization (LHCP, RHCP). The capabilities of this new type of slot of maintaining good circular polarization radiation performances for beams scanned over a large angle range have been verified. A Rotman lens has been designed to feed a 15 slotted waveguides array generating a set of independent beams covering the ±60° angle range. Each slotted waveguide contains 16 annular slots.