This paper gives a design method of power transmitter for electric vehicle wireless charging applications. Uniform magnetic field is targeted for better modular application and misalignment adaption. Rectangular coil and spiral windings are specially selected for evaluation. The compound winding is chosen for optimization. The magnetic flux density is studied by calculating the mutual inductance per area. By optimally choosing the turns and pitch distances of the spiral winding, a uniform magnetic field is achieved. Using finite element analysis, the performances of the transmitter are evaluated, including its tolerance to misalignment.