Fabrication and simulation of the planar inductors

Abstract

In this study a planar inductor with excellent electrical characteristics was successfully prepared by screen printing of high solid content alloy magnetic pastes onto copper clad laminates (CCL) and then cold-isostatic pressing to increase the packing density In order to solve the problem of low electrical resistivity of alloy powder resulting in excessive eddy current loss for power inductor application an epoxy resin vehicle was added to form an insulating layer on the surface of the mixture of FeSiCr alloy and carbonyl iron powders A high solid content alloy magnetic paste was then prepared by adding a small amount of diluent to meet the flow characteristics required in screen printing As the magnetic flux density for an inductor is concentrated magnetic saturation is easily achieved The center column generated by mechanical drilling in the center of the planar inductor was filled with magnetic paste to make the distribution of magnetic flux density more uniform which prevented the magnetic saturation At the same time the inductance value can be increased The planar inductor of size 8 5mmx7 0mmx0 4mm with an inductance value of about 2 7μH at 1MHz a quality factor of 10 to 13 and the degradation rate of about 5% at a DC bias of 2 5A can be successfully prepared in this study In addition Maxwell software a low-frequency electromagnetic field simulator issued by Ansys was used to simulate the effects of the coil geometry and magnetic paste formulation on the static magnetic field environment magnetic flux density distribution and the electromagnetic properties of the planar inductors which is helpful to find the optimal parameters The differences between the simulation and the experimental results for the planar inductors were compared suggesting that the deviation between them was within 6%

Date of Award	2020
Original language	English
Supervisor	Hsing-I Hsiang (Supervisor)