Polymer Magnetic Composite Core Based Microcoils and Microtransformers for Very High Frequency Power Applications

Area of Science:

• Materials Science
• Electrical Engineering
• Microfabrication

Background:

• Traditional inductive components face limitations in operating frequency and performance.
• Bridging the gap between non-magnetic and magnetic cores is crucial for advanced microelectronics.

Purpose of the Study:

• To present a rapid, cost-effective fabrication process for wafer-level micro inductive components.
• To introduce novel polymer magnetic composite (PMC) cores for enhanced performance.
• To evaluate the electrical characteristics of fabricated inductors and transformers.

Main Methods:

• Optimized molding, casting, and demolding process using Teflon.
• Fabrication of cylindrical PMC cores with NiFeZn powder and Araldite epoxy on FR4 substrates.
• Integration of solenoidal coils (Au wire) and transformer structures.
• Encapsulation of components with an epoxy-based magnetic composite.

Main Results:

• PMC cores with 65% NiFeZn powder achieved 2 µH inductance up to 50 MHz with a peak quality factor of 13.
• Fabricated 1:1 transformers demonstrated 84% maximum efficiency and 96% coupling factor.
• Encapsulation process improved mechanical robustness without significant performance degradation.

Conclusions:

• The developed PMC cores offer a viable solution for high-frequency micro inductive components.
• The rapid prototyping and cost-effective fabrication process are suitable for batch production.
• Encapsulation enhances the practical application of these microelectronic components.