This paper proposes a single coaxial feed rectangular microstrip antenna aiming at GPS application. The antenna has a simple design with conventional FR4 substrate which is easy to be fabricated. Computer Simulation Technology (CST) Microwave Studio software is used to numerically design the antenna. The proposed antenna has rectangular patch with rectangular slots in the middle and the edge of the patch. The antenna has a working frequency of L1 band GPS (1575 MHz), Coaxial feeding technique is applied to affect the current distribution and resulting in right-hand circular polarization. Simulated results indicate that the proposed antenna has achieved the desired specifications with S11 of -44.07 dB, axial ratio of 1.52 dB, bandwidth of 46.8 MHz and gain of 3.071 dB. The proposed design is fabricated and the measurement results agree with the simulated and achieve all of desired specification.