John Papapolymerou | email@example.com | www.egr.msu.edu/people/profile/jpapapol
Research in the High-Frequency Laboratory covers RF/microwave/mm-wave/THz circuits, antennas and packaging for wireless communication systems, sensors and radars.
3D RF Circuits and Modules Using Additive Manufacturing Techniques
The goal of this research aims at developing high performance, cost-effective RF and mm-wave circuits and modules that can be utilized in future wireless communication, radar and sensing systems using additive manufacturing techniques. In particular, we have developed three dimensional RF and mm-wave transmission lines, interconnects, filters and antennas using aerosol jet and polyjet 3D printing techniques with competitive performance as compared to higher cost traditional fabrication methods. In addition, we have demonstrated a 3D printed RF package for a low noise RF amplifier up to 20 GHz. We have also combined 3D printed RF circuits with flexible PCB based fabricated circuits for application in current low and high RF power wireless systems. Utilization of 3D printing techniques on diamond substrates is also under investigation.
Development of Magnetic Thin Films for RF Circuits
Our group is also interested in developing novel RF circuits utilizing thin magnetic films that can be developed using traditional semiconductor fabrication technologies. In particular, we are collaborating with Prof. John Zhang’s group at Georgia Tech to develop RF circuits comprising of thick (>10 um) magnetic films composed of magnetic nanomaterials that can be deposited on any substrate with standard fabrication methods. These films can be utilized for the development of planar, monolithically integrated high frequency circuits such as isolators, circulators, phase shifters and frequency selective limiters (FSLs). The FSLs can be used for mitigation for RF interference problems in a crowded RF spectrum environment. Currently, there is a technological gap in the development of magnetic films compatible with standard IC fabrication technologies. We have recently shown for the first time –to the best of our knowledge- RF Coplanar Waveguide (CPW) transmission lines on 5um thick CoFe2O4 magnetic spinel material that was deposited on a glass substrate with a layer-by-layer low cost technique. The magnetic nanoparticles have a size of about 10nm. The relative magnetic permeability of the material is estimated to be around 50 from measurements. The CPW transmission lines showed increased group delay –as compared to lines with no magnetic film- consistent with the film thickness. Currently, we are investigating the transmission line performance effects from applying a DC magnetic bias, as well as CPW lines on thicker (~50 um) magnetic film.