Concrete structure needs to be inspected in order to prevent structural failures. In concrete inspection activity, ground-penetrating radar (GPR) is one of the tools used to detect the location of steel reinforcement in concrete without the need for invasive action. In this research, GPR was designed for concrete inspection applications. GPR for concrete inspection application is designed using frequency modulated continuous wave (FMCW) and it works on ISM bands with a frequency range of 2.4-2.5 GHz. FMCW GPR system is composed using LimeSDR Mini as transceiver module, rectangular patch antenna array integrated with unequal Wilkinson power divider as first type RX antenna, Vivaldi antenna array as second type RX antenna, and single element Vivaldi antenna as TX antenna. Tests for the designed GPR system are conducted using a concrete with steel reinforcement bar, an empty cardboard box, and a metal pipe inside cardboard box. The test results show that the GPR system can produce radar image and locate steel reinforcement bar inside concrete and cardboard box.