Ku Band Dual-Polarized Microstrip Array Antenna with Wide-Band and Low Side-Lobe

Abstract

A $4 \times8$ dual-polarized microstrip antenna array in the need of synthetic aperture radar (SAR)’s engineering requirement is proposed in this thesis. The design of antenna element structure is based on the common aperture-coupled antennas. To improve the impedance bandwidth, some metalized via holes are introduced surrounded the feeding lines. To improve the isolation and reduce the cross polarization, two-layered power divider networks are optimized and antiphase technique is introduced. Furthermore, array weighting is used to control the side-lobe level of the antenna. The simulated results indicate that an impedance bandwidth of 1.5 GHz with VSWR less than 1.5 can be realized. The isolation between the two ports is better than 42 dB, and the cross-polarization levels are over 50 dB in both E and H planes. By using the Chebyshev current distribution, the side-lobe level in azimuth direction is lower than -20 dB.