Gigahertz-Band Integrated Magnetic Inductors

The demand on mobile electronics to continue to shrink in size while increasing in efficiency drives the demand on the internal passive components to do the same. Power amplifiers require inductors with small form factors, high quality factors ( $Q\text{s}$ ), and high operating frequency in the single-digit gigahertz range. This paper explores the use of magnetic materials to satisfy the demands of power amplifier inductor applications. This paper then discusses the optimization choices regarding material selection, device design, and fabrication methodology. The inductors achieved here present the best performance to date for an integrated magnetic core inductor at high frequencies with a 1-nH inductance and peak $Q$ value of four at about 3 GHz. Such compact inductors show potential for efficiently meeting the need of mobile electronics in the future.