To address the decline in coupling coefficient and transmission efficiency of traditional flat solenoidal magnetic coupling structures in wireless power transfer (WPT) systems under lateral misalignment, this article proposes an engineering-oriented concave flat solenoidal coil design method with enhanced misalignment tolerance. First, based on the first harmonic approximation (FHA), the voltage gain characteristics of typical compensation topologies are analyzed, and an analytical relationship between voltage gain G and mutual inductance M is established. It shows that reducing the sensitivity of M to lateral displacement can improve system tolerance to misalignment. Secondly, from the perspective of coil arrangement, the effects of winding distribution, turn spacing, and concave end angle on magnetic field uniformity and coupling coefficient retention are investigated, and trade-off and optimization methods are proposed. Subsequently, magnetic coupling structures are modeled in Ansys/Maxwell, and their magnetic field distributions and coupling variations under lateral misalignment are compared. The results shows that a non-uniform winding distribution with a 30° concave end angle can maintain a high coupling coefficient and stable transfer performance under ±60% lateral displacement. For lightweight and integrated design, the secondary side is implemented with a flexible printed circuit board (FPC) coil, meeting the miniaturization and high-power density requirements of medium- and small-scale portable devices. Finally, a 100 W prototype shows that within a misalignment range of ±15 mm along the X-axis and ±30 mm along the Y-axis, output voltage fluctuation is within 4%, and maximum transmission efficiency reaches 87.3%. These findings validate the effectiveness and engineering applicability of the proposed magnetic coupling structure in enhancing lateral misalignment tolerance and system performance.