This thesis proposes a mechatronic suspension system design, and investigates the performance benefits of vehicle suspension systems employing it. The mechatronic suspension strut consists of a ball-screw type inerter and permanent magnet electric machinery, such that the system impedance is a combination of mechanical and electrical networks, using the analogy between the mechanical and electrical networks. Network synthesis methods are then introduced such that performance optimization can be carried out by simple networks with reasonable elements. In application, we consider a quarter-car model, and compare the performance benefits with the traditional suspension, the suspension employing inerters and the mechatronic suspension system. From the results, the mechatronic suspension is better than the other two. We further propose a nonlinear mechatronic suspension, by considering the elastic effect, backlash and friction, and conduct a series of experiments to verify the model.