Date of Award

Fall 12-2022

Embargo Period

1-2024

Access Type

Dissertation - ERAU Login Required

Degree Name

Doctor of Philosophy in Electrical Engineering & Computer Science

Department

Electrical Engineering and Computer Science

Committee Chair

Eduardo Rojas

First Committee Member

M. Ilhan Akbas

Second Committee Member

Jonathan Snively

Third Committee Member

Brian Butka

Fourth Committee Member

Radu Babiceanu

College Dean

James Gregory

Abstract

Additive manufacturing (AM) has proved effective in rapidly prototyping passive RF and microwave devices. Technological advancement has promoted the development of diverse technologies to exploit additive manufacturing capabilities, such as reduced manufacturing time, geometry and material freedom, and ad-hoc fabrication. Therefore, as the AM technologies mature, they will become high-quality replicators that produce low-cost, complex-shaped, and reliable devices made of novel materials. Considering the benefits of AM technologies and the fact that wireless communication systems have expanded for many applications, requiring expanded operational conditions, have led to research opportunities to explore AM technologies and provide endurance RF and microwave components to extreme conditions.

Space agencies worldwide have shown interest in using AM technologies for aerospace applications. Feasibility studies have been applied to AM technologies, including fused deposition modeling (FDM) and microdispensing. Since FMD extrudes thermoplastic filaments, many of these materials have been tested in the space environment, such as acrylonitrile butadiene styrene (ABS), polyetherimide (PEI) ULTEM®,, polycarbonate (PC), high-density polyethylene (HDPE), polyetheretherketone (PEEK), and Onyx®, (Nylon). In this work, FDM is selected to fabricate substrates made of ABS and ULTEM®, 9085. An equivalent process called fused filament fabrication (FFF) is also utilized to produce a substrate comprising micro-carbon-fiber-filled nylon (Onyx®,). Material jetting is another AM technology explored in this dissertation to create ceramic substrates made of Yttria-stabilized zirconia (YSZ).

Besides, the patterned metal layers of the passive RF components are made by microdispensing conductive paste on the additively manufactured substrates. Two different conductive pastes have been explored in this work. Dupont CB028 is a silver paste designed for screen printing processes. However, it has been extensively used in the scientific community due to its good electrical properties and low-temperature curing process. Ferro 5542 is a platinum paste designed for screen printing, but its rheology properties allow microdispensing. Unlike Dupont CB028, Ferro 5542 requires drying and sintering the past to improve its mechanical and electrical properties. Due to the high-temperature sintering process, Ferro 5542 can be only used on high-temperature material, such as ceramics.

This dissertation explores the capabilities of AM technologies and different materials to fabricate passive wireless components, such as sensors and antennas, to improve their wearability and resilience under harsh conditions. Therefore, the additively manufactured components are exposed to high-temperature and ionizing radiation conditions to characterize their temperature endurance and shielding effectiveness. Besides, a passive wireless sensor that comprises an AM antenna, a printed nanocomposite transducer, and an RFID tag is characterized to detect micrometeoroids and orbital debris impacts. This work also includes the study of 3D geometries to provide small-size antennas or improve the antenna performance compared to their planar counterparts, which is helpful, especially when the antenna is in a restrictive space or with difficult access. In addition, a reconfigurable antenna that provides a tunable gain and frequency beam scan is presented as an alternative to reduce the complexity of the RF front end by avoiding the need to use phase shifters.

Additional Files
GS9_Acceptance_Mejias.pdf (405 kB)
Download

Share

COinS