Finite Element Analysis of Planar Inductors With Soft Magnetic Encapsulation Materials

The rise of 5G, artificial intelligence, and other applications drives the demand for planar inductors based on PCB processes, due to the advantages of compatible processes, flat shapes, high power densities, reduced volumes, etc. In this paper, six kinds of soft magnetic encapsulation materials (SMEs) were selected to prepare planar dual-layer spiral inductors (PDSI). The actual PDSI device, as well as the six kinds of SMEs, were then processed. Based on the tested relative permeability of SMEs, FEM models were built and calibrated through the actual PDSI structures. Furthermore, FEM models of single-layer, double-layer, and multilayer inductors were established respectively, with analysis of the differences in magnetic properties. The results reveal that both Land Q of the PDSI exhibit a positive linear correlation with the relative permeability of the SMEs, and SMEs with high permeability limit the magnetic leakage. The multilayer inductor could achieve similar Land
$Q$
values with a smaller area compared with the planar inductor. However, the increase in thickness limits their application in thin devices. The models can be adjusted to match the SME properties and size parameters of the actual manufacturing process, contributing to simplified calculations for inductor design and performance analysis. Based on such analysis, the planar inductor designs based on in-house SME and PCB-compatible processes are adjusted for high-frequency applications.