W-band Finite Ground Coplanar Waveguide (FG-CPW) using Laser Enhanced Direct-Print Additive Manufacturing (LE-DPAM)

Design, fabrication, and measurement of finite ground coplanar waveguides (FG-CPWs) operating up to 110 GHz is demonstrated using additive manufacturing (AM) technology. FG-CPWs were fabricated using laser enhanced direct-print additive manufacturing, where laser-machining at 355 nm or 1064 nm wavelength was employed along with fused deposition modeling and micro-dispensing in a single digital manufacturing platform. This approach provides high dimensional accuracy that is required by mm-wave packaging systems. The characterization of laser machining at wavelengths of both 355 nm and 1064 nm was examined with specific focus on the feature size and dimensional accuracy. Several FG-CPW designs for 50 and 60 ohms are characterized and compared against a FG-CPW line on a commercially available calibration substrate. Attenuation as low as ~0.3 dB/mm at 110 GHz is achieved. To the best of the authors' knowledge, this is the first reported experimental result for transmission lines at W-band using laser enhanced direct-print additive manufacturing (LE-DPAM).