Aerosol-Jet Printed High-<i>Q</i> Quasi-Optical FSSs on Flex Substrates Using a Novel Parylene Lift-Off Process

This article introduces a new method to fabricate low-loss terahertz (THz) frequency-selective surfaces (FSSs) on flexible substrates. The process involves the printing of periodic metallic patterns on glass substrate using aerosol-jet printing (AJP) technology and silver-based nanoparticle ink followed by a novel lift-off process using thin parylene-C. The printed structures on glass can be sintered at high temperatures to achieve high conductivity silver structures. These printed structures are lifted of using a thin (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10~\mu $ </tex-math></inline-formula>m) parylene-C. Use of thin parylene-C reduces the effective dielectric losses. Several designs are demonstrated including parallel wire-grid and a tilted I-shaped polarizer, and a few THz FSS bandpass and band-stop filters. All the prototypes are designed, fabricated, and experimentally validated. The proposed FSSs can find applications in the next generation of low-loss THz flexible electronics.