Free-Form RF Sensing: Multifunctional, Multilayer Microwave Design on Doubly-Curved Fiberglass Laminates

Additive manufacturing has revolutionized traditional manufacturing processes, allowing for novel functionalities and unique form-factors within existing systems. Oftentimes, it is desirable to integrate electrical and/or communication technology into an existing part without disturbing its existing structural properties- such a process becomes especially challenging on surfaces with large curvatures or surfaces internal to an existing part. In this work, we utilize a novel multilayer insert-based approach to integrate an RF sensing circuit directly within an electrical glass (E-glass) ogive nose cone. These inserts enable detection of X-band frequency signals, utilizing a fully aerosol jet-printed ground plane, antenna, and transmission lines, alongside discrete amplifiers, envelope detectors, and capacitor networks. This work demonstrates and overcomes constraints imposed by the substrate's material properties such as impedance matching and loss.[MCJ1] Electromagnetic performance was verified both experimentally and utilizing Ansys HFSS simulations, and the impacts of curvature on circuit performance were analyzed. The resulting RF system demonstrates not only full functionality, but the potential for such techniques to be expanded towards the integration of microcontroller technology and various other sensors directly atop highly curved substrates.