The purpose of the thesis is to review the characteristics of the antennas used in SAR (Synthetic Aperture Radar) systems and the theoretical elaboration of the antenna of a particular SAR device. In the first part of my dissertation I will present the most important characteristics of antennas and transmission lines, and the theoretical background of imaging radars. In this section, I summarize the properties of the antennas that are critical to a SAR system. In the middle of my dissertation I'm dealing with the topic of antenna arrays and microstrip antennas which are required for the design of the antenna. Then I present the process of the antenna design in detail using CST Microwave Studio. The final layout is an 8X2 microstrip antenna array with RO4003C used as dielectric. The antenna resonance frequency is 9.4 GHz, where the return loss is -20.1 dB. Feeding is done via coaxial cable and microstrip transmission lines. Finally, I discuss the measurement methods of antenna parameters. I describe the measurements of radiation pattern, gain, bandwidth, polarization, and input impedance.