Development of Low Sidelobe Level Array Antenna for Synthetic Aperture Radar Sensor

The radiation pattern of the array antenna is an important characteristic in the synthetic aperture radar (SAR) sensor to maintain the quality of the images. In this work, an array antenna consists of five elements square microstrip antenna (SMA) having a low sidelobe level for SAR sensor is presented. The proposed antenna is designed to propagate in circular polarization with a corner-truncated technique. The low sidelobe level is obtained by implementing the Chebyshev polynomial to distribute the power to each element of the patch. For five elements square array antenna, the simulated axial ratio bandwidth (<3 dB) of about 11.2 MHz (0.88 %), which is consistent with the measured fabricated model of 10.5 MHz (0.83 %). The maximum sidelobe levels of the proposed antenna for measurement and simulation are about 20.0 dB and 21.5 dB, respectively. The both measured and simulated results are in line with the theoretical design made by using Chebyshev polynomial of 20 dB. The low side lobe level and reasonable axial ratio bandwidth indicate the antenna is satisfying the specifications of SAR sensor. (paper)