Design Procedure for Compact Dual-Circularly Polarized Slotted Substrate Integrated Waveguide Antenna Arrays

In this paper, a complete design procedure of low-profile dual-circularly polarized slotted substrate integrated waveguide antennas is developed at the Ku-band frequencies. The design method includes a recipe for controlling the beam squint angle, determining the optimum slot aperture distribution, and tapering slots coupling and excitation to increase the gain/efficiency and reduce the array sidelobe levels. The structure is designed in such a way to provide dual circular polarization and improve the radiation characteristics including reduced sidelobe levels using optimized symmetric nonuniform coupling factors and tapering the lengths of the slots. The radiation performance of the fabricated 64x12 slot antenna array has been tested using a planar near-field range measurement. The beam tilt angles in elevation, peak gain, cross polarization component, and sidelobe levels have been measured and compared to previously designed 32 x 13 and 16 x 12 slot arrays.