Micro Additively Manufactured Suspended Stripline for Sub-THz Applications

In order to meet the increasing demands of sub-THz applications, recent developments in micro-metal additive manufacturing (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \text{AM}$</tex>) allow the creation of miniature devices with intricate geometries without any post impression steps. In this work, a novel technique for creating a new type of suspended stripline transmission line with an operating frequency up to 600 GHz is presented. The printing method achieves micron-scale resolution and precision by using a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \text{AM}$</tex> localized electrodeposition procedure. The alignments are done by using the same tip of this <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \text{AM}$</tex> machine, that works in a similar way to an atomic force microscope (AFM) tip. The suspended stripline is aligned with a coplanar waveguide (CPW) on a photolithographically patterned fused silica substrate (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$15 \times 15$</tex> mm) and then 3D printed. By combining traditional production methods with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \text{AM}$</tex> precision, this approach opens the door to a new generation of high-performance devices for sub-THz and millimeter-wave frequencies.