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Suspended finite ground coplanar waveguide (FG-CPW) interconnects, fabricated with laser-enhanced direct print additive manufacturing (AM), are modeled and characterized in this work. The study focuses on the variation of characteristic impedance and attenuation with design geometry. Acrylonitrile butadiene styrene (ABS) is printed with fused deposition modeling (FDM) to form 10-mm-long suspended ABS bridges and Dupont CB028 is microdispensed to realize conductive traces on the ABS bridges. Femtosecond pulsed laser machining in the ultraviolet range is combined with the AM to create gaps ranging from 8 to 92 μ m in width on either side of a signal line to define the FG-CPW. Three different suspended interconnects are designed, where the total linewidth (signal line plus gaps) is kept constant at 300 μ m for all designs, but the aspect ratio (AR) (signal linewidth divided by total linewidth) is varied. Two multiline thru–reflect–line calibrations are performed to measure each design: one uses printed calibration standards and the other employs a commercial calibration substrate. The attenuation of the interconnects at 30 GHz is 0.28, 0.13, and 0.06 dB/mm for ARs of 0.95, 0.87, and 0.38, respectively. The laser machining of the gaps results in partial substrate removal, which increases the characteristic impedance by approximately 11%. The impact of fabrication tolerances is examined. 

Project Connect (PC) is an immersive professional development program designed to increase the number of students from underrepresented groups in engineering who pursue careers in the microwave engineering and related fields. Most of the professionals in this area have been educated in the electrical engineering (EE) field with a focus on applied electromagnetics, antenna theory and communication systems. The electromagnetics class in a typical electrical engineering undergraduate program involves vector calculus and abstract concepts without, in many cases, the right facilities or equipment to aid experiential learning. This leaves most students perplexed and disinterested in the field, while they do not fully realize the wealth of opportunities that lie beyond this course. This problem is even more pronounced for students from underrepresented groups as they may have less exposure to the professional and academic opportunities in microwave engineering. Project Connect was birthed out of the need to keep these students engaged in the field by exposing them to a broader view of the field and the impact that they can have on technology. Each year, the PC program is housed within the Institute of Electrical and Electronics Engineers (IEEE) International Microwave Symposium (IMS). IMS is the flagship conference of the Microwave Theory and Techniques (MTT) Society and is based in North America. The typical attendance at the conference is over 9,000 and there is an associated industry exhibition with more than 700 companies. PC hosts approximately two dozen underrepresented students for four days of community building and professional development, most of whom are juniors or seniors in undergraduate programs, along with a smaller cohort of first-year students in graduate programs. The groups, consistently mixed in gender and ethnicity, get an opportunity for direct interaction with fellow PC participants, practitioners and academics, and leaders in the field and of the MTT society. This interaction is central to the success of the program, and the integration with IMS is representative of the important role that professional societies can play in diversifying STEM participation [1]. PC has been in operation since 2014 [2-5] and is sponsored jointly by the National Science Foundation and the IMS Organizing Committee. 

Additive manufacturing (AM) is increasingly being shown as a viable technology for the fabrication of complex 3D structures. For microwave components, the combination of laser processing and AM techniques has been reported to enhance the performance and frequency limits of the devices. In this paper, a process to fabricate a 200 μm × 200 μm × 200 μm vertical interconnect that combines fused deposition modeling (FDM), micro-dispensing, and picosecond laser machining is studied. A test structure that includes two vertical transitions is designed, fabricated, and tested, as a performance benchmark. The 4 mm long structure shows a low dissipative loss (2.5 dB at 45 GHz) and excellent frequency response up to mm-wave frequencies. The described structure will help to enable the fabrication of high-performance structural RF electronics.