Wideband Circularly Polarized Array Antennas With Sequential-Rotation Polarization Grid and Simplified Full-SIW Feeding Networks
Yixuan Zhang, Yong‐Chang Jiao, Li Zhang
Abstract
Two wideband circularly polarized (CP) antenna arrays are proposed, based on sequential rotation (SQR) arranged polarization grid and specially designed wideband full-substrate integrated waveguide (SIW) SQR feeding network. First, as the CP array element, an SIW-excited log-periodic dipole array (LPDA) loaded with an inhomogeneous polarization grid is designed. Then, the element with the grid is extended into a 2×2-element SQR array, and a wideband planar SIW-feeding cavity is used to provide the full-SIW array feeding. The SQR configuration is simplified by exploring the symmetric property of the LPDA dipole elements for 180° phase shift. Finally, in order to solve the high sidelobe problem existing in the first array design, another full-SIW array configuration with a new 3-D SIW-feeding cavity for the purpose of element spacing reduction is proposed. Another SQR network simplification method is studied here in favor of the 3-D SIW-feeding cavity, in which the out-of-phase power division property of the SIW E-plane junction is explored. With this configuration, a much lower sidelobe result is obtained by the second array. The measured results indicate that both arrays have advantages of wide CP working bandwidth (37%), high efficiencies (~80%), and also wide 3 dB gain bandwidth (39%).