Signal transmission analysis is performed for a serial advanced technology attachment (SATA) cable assembly using a three-dimensional (3D) electromagnetic field simulation. In this work, SATA cable assembly consists of the connector, PCB and cable in series. Three components and their assembly are investigated with their differential mode S-parameters. Also, the insertion loss, reflection loss and differential impedance of the components are calculated to analyze their signal transmission characteristics. Each component has approximately 100 of the differential impedance. However, their high-frequency responses such as insertion loss and reflection loss show different characteristics. While the connector and cable present the excellent signal transmission performance, the printed circuit board (PCB) has lower characteristics despite the shortest trace length. The insertion loss and reflection loss of SATA cable assembly are investigated and have a similar tendency with those of the PCB. These results verify that signal transmission properties of the SATA cable assembly are affected significantly by the PCB with the largest loss.