## 5 Application Areas  
The primary function of electromechanical systems is the effective and controlled transmission of energy. Although structural variations exist depending on the application field, torque density often emerges as a critical performance indicator in these systems. Magnetic gear systems, with their contactless torque transmission structures, are considered  
Figure 16: Frequency-dependent core losses for different materials. a significant solution, particularly in scenarios where reducing friction-related losses and minimizing maintenance requirements are essential. Recent reviews emphasize the expanding role of magnetic gears in mechanical power transmission, especially in sectors like transportation and robotics, where high reliability and low maintenance are critical [100]. Table 5 systematically summarizes different magnetic gear topologies, types of core materials used, gear ratios, volumetric torque densities, and manufacturability indices. These attributes directly influence the performance criteria of magnetic gear systems and stand out as critical parameters when selecting suitable systems for specific application areas. This comprehensive comparison provides a foundational understanding of how magnetic gear technologies are positioned across various sectors. Additionally, the impact of core materials used in different applications on overall system performance is frequently emphasized in the literature. Particularly in complex MG topologies such as transverse flux structures, material selection plays a decisive role in torque density, losses, and manufacturing ease. When comparing the torque densities of transverse flux MGs with different pole piece materials, it has been reported that a higher torque density can be achieved with SMC materials. This is attributed to more homogeneous field distribution within the ferromagnetic segments and improved flux conduction. However, to support a high torque capacity, it is generally recommended that transverse flux MGs be made from steels with high saturation flux density and high relative permeability. While SMC-based structures offer ease of block-form manufacturing, they may lead to increased iron losses in some scenarios [78]. Moreover, certain structural applications in the literature support these \begin{table}
\begin{tabular}{c c c c c c} \hline
**MG Topology** & **Material Type** & **GR** & **VTD** & **Application Area** & **Fig.Num.** & **Ref.** \\ \hline
**Linear MG** & Steel 1010-M400 & 3.25:1 & 1.7 MN/m3 & Electric Vehicles & Figure 3h & [101] \\
**Axial MG** & Silicon Iron & 5.75:1 & 70 kN/m3 & Aerospace & Figure 3e,f & [102] \\
**Spoke Ferrite MG** & Steel 1018 & 4.25:1 & 84.4 kN/m3 & Robotic Systems & Figure 3b & [46] \\
**Cycloidal MG** & Steel 1018 & 22:1 & 141.9 kN/m3 & Robotic Systems & Figure 2f & [25] \\
**Spoke-Type Coaxial MG** & Steel 1018 & 5.5:1 & 92 kN/m3 & Renewable & Figure 3b & [31] \\
**Surface-Mounted** & Steel 1018 & 5.5:1 & 98.1 kN/m3 & Robotic Systems & Figure 3c & [102] \\
**Coaxial MG** & NdFeB & Steel 416 & 3.75:1 & 80.6 kN/m3 & Electric Vehicles & Figure 2h & [103] \\
**Transverse Flux MG** & Ferrite–NdFeB & 10.5:1 & 100 kN/m3 & Electric Vehicles & Figure 3g & [104] \\
**Concentric-Type MG** & Steel M 19 & 5.75:1 & 162 kN/m3 & Electric Vehicles & Figure 3b & [105] \\
**Spoke Coaxial MG** & NdFeB & 33:1 & 300 kN/m3 & Robotic Systems & Figure 2f & [106] \\
**Cycloidal MG** & NdFeB 42 & Steel M 19-M27 & 7.67:1 & 221 kN/m3 & Aerospace & Figure 3e & [26] \\
**Dual-Stack Coaxial MG** & NdFeB 50 & 5:1 & 11.07 kN/m3 & Electric Vehicles & Figure 3e & [107] \\
**Axial Flux MG** & NdFeB 35 & Steel 20 & 2.11:1 & 14.7 kN/m3 & Electric Vehicles & Figure 3f & [108] \\
**Axial-Flux MG** & NdFeB 35 UH & 2.11:1 & 14.7 kN/m3 & Electric Vehicles & Figure 3g & [109] \\
**Dual-Flux-Modulator** & Steel B65A800 & 5.5:1 & 55.2 kN/m3 & Robotic Systems & Figure 3g & [109] \\
**MG** & NdFeB & & & & & \\ \hline \end{tabular}
\end{table} 
Table 5: Summary of magnetic gear topologies, core materials, and application areas. evaluations.