Aerosol-Jet Printed Transmission Lines for Microwave Packaging Applications

This paper presents a low-loss microstrip line (MSL), entirely fabricated using aerosol-jet printing (AJP) technology directly to a monolithic microwave integrated circuit (MMIC) chip to achieve high-speed on-chip connectivity. AJP is a direct write fabrication method capable of printing materials with viscosity ranging from 1-1000 cP, with a printing resolution and alignment precision of 10 and 2 μm, respectively. The length of the printed transmission line is 2 mm, and the S-parameters are measured from 500 MHz to 18 GHz. In this paper, the MSL is first printed on printed circuit board (PCB), and the fabrication process is optimized to reach a transmission loss of 0.3 dB/mm at 18 GHz. Subsequently, the MSL is printed atop an MMIC architecture to achieve a transmission loss under 0.9 dB/mm at 18 GHz. These results clearly show the potential of using direct printing of MSL as an alternative to conventional wire bonding for wide-bandwidth MMIC electronics packaging applications.