The wideband microstrip antenna is a development of the purpose of this study is to design a wideband antenna at a frequency of 1030 MHz-1090 MHz which will be applied to the Monopulse Secondary Surveillance Radar (MSSR) antenna. The study uses a single microstrip antenna using the DGS (Defected Ground Structure) method and the DMS (Defected Microstrip Structure) method, which can increase the antenna bandwidth. From the results of the element simulation, adding the DGS (Defected Ground Structure), and DMS (Defected Microstrip Structure) structures to the single antenna obtained a result of 2.83 dB.