Printed electronics for extreme high temperature environments

There is a rapidly growing interest in the development of electronic microsystems that can maintain functionality in high temperature environments, particularly in power generation and aircraft engines where the operating temperatures can exceed 500 degrees C. The current work presents a major advancement toward development of additively printed electronics made for high temperature applications. Here, the electronic system is represented by gold-based electrical structures that have been printed on 3D printed ceramic substrates. The substrate is alumina-based with a purity level of 99.8% and was fabricated through photopolymerization digital light processing (DLP). An aerosol jet printing technique that can deposit an ink stream down to 10 mu m was utilized to fabricate gold-based electronic structures. The gold ink printability and its adhesion to the ceramic substrate were assessed. Furthermore, the microwave dielectric constant and loss tangent of the alumina substrate were extracted through measurements of the scattering parameters of transmission lines up to 750 degrees C. A 3D printed conformal broadband antenna was successfully fabricated and tested at temperatures up to 850 degrees C. The printed gold structures showed excellent stability and adhesion after aging at temperatures up to 750 degrees C. The substrate dielectric constant slightly increased for temperatures up to 450 degrees C and significantly increased for temperatures between 450 degrees C and 750 degrees C. It was found that the dielectric loss increased as the temperature increased. This work presents an entirely additive manufacturing-based approach to fabricate electronic components including substrates, interconnects, and RF elements for high temperature applications.