Research Scientist Binghamton University, NY, United States
Direct-Write (DW) printed electronics is a rapidly developing technology that is becoming relevant for real-world applications. Our goal is to leverage industry/academia developed tools, materials, equipment, and processes for direct-write printing and additive manufacturing (AM) that advance fabrication technology of radio frequency (RF) circuit elements. Direct-Write printing enables the selective deposition and patterning of both dielectric and conductive materials in a multi-layer fashion to create high-resolution 3D circuit elements on both flat and complex geometries. A hybrid circuit fabrication approach was chosen using conventional low-K substrates and copper foil circuitry with GaAs active die. Printed RF elements were placed in the circuit where there was a realizable size-weight-power-cost (SWAP-C) advantage in terms of better performance, size reduction, or faster build time. This technology is particularly relevant for millimeter-wave and micro-wave systems where printed feature size is tens of microns. Aerosol Jet (AJ) is considered immediately applicable for use with AM because of its fine printed feature size and its use of digitally driven data from CAD files for multi-axis control of the deposition tool and ability to print different materials. Interconnects formed by AJ printing use shaped patterns of dielectric and nano-silver ink to form controlled impedance connections and is a more manufacturable option compared to wire bonding. This paper demonstrates several printed circuit element applications where reduced size and increased performance are advantageous for near-term commercialization. Demonstration articles include coplanar-waveguide transmission line, bare die interconnection, 3D coupling transformer, conical bias inductor, embedded PIN diode connection, MIS capacitor ribbon bond and various conformal antenna configurations. We have conducted S-parameter testing over frequency to measure performance and compare to conventionally fabricated parts. Thermal cycle reliability testing was performed to evaluate service life and a low-loss conformal coating was evaluated for environmental protection with no degradation in RF performance.