A Fully 3D Printed Waveguide and its Application as Microfluidically Controlled Waveguide Switch

  • Author / Creator
    Khan, Sabreen
  • Hollow rectangular waveguides are employed extensively in microwave and millimeter wave devices owing to their relatively high power handling capabilities and low losses, particularly at higher frequencies, compared to transmission lines. However, the fabrication of such metal waveguides suffer from the challenge of needing expensive techniques and specialized labor, which is exacerbated as frequency increases into the millimeter- wave band, due to the increasingly demanding requirements in mechanical precision for smaller feature sizes, owing to the inverse relationship between wavelength and frequency. As a result, alternate techniques have been explored to make unit level manufacturing of waveguides, economical. By the advancements of 3D-printing, also known as additive manufacturing (AM) technology, localized manufacturing of customized 3D structures offer the potential of abating the fabrication cost of such hollow rectangular waveguides for small to medium market size such as that of Satellite communication. As an emerging manufacturing alternative, 3D-printing has found widespread applications in rapid prototyping and manufacturing of high geometrical complexity components, over the years. This thesis reports the design, fabrication and characterization of a waveguide fabricated with 3D-printing technology, and a microfluidically controlled waveguide switch, operating at K-band. The waveguide body is printed using a bench top 3D-printer using thermoplastic substrate Acrylonitrile butadiene styrene (ABS), which gives the waveguide it’s structure. In order to achieve functionality, the conductive part is realized by automated deposition of conductive silver ink to coat the waveguide walls. The fabricated waveguide is characterized exhibiting a total measured insertion loss of better than 0.11 dB/cm for the entire K-band. Its attenuation and propagation constants are computed for the K-Band using a multi-line technique. The results show reasonable agreement with simulations depicting 3D-printing followed by ink dispensing as an alternative waveguide manufacturing technology. Additionally, a microfluidically controlled Eutectic Gallium Indium (EGaIn) liquid metal is integrated with the 3D-printed waveguide and a novel reflective waveguide switch is implemented. The measured S-Parameters are in accord with simulations, exhibiting ON State insertion loss and OFF State isolation to be better than 0.5 dB and better than 15 dB for the entire K-Band, respectively. Furthermore, the switch’s performance with respect to changes in ambient temperature has been studied and was found fairly consistent. To our knowledge, this is the first time that fully 3D-printed waveguide has been investigated wholly using a desktop 3D printer, with thermoplastic and conductive silver ink. In addition, this thesis reports the development of a novel microfluidically controlled reflective waveguide switch, which is incorporated into the reported 3D printed waveguide as well as conventional rectangular waveguides, exhibiting the potential of such technology for rapid prototyping of functional RF devices. To enhance the performance of the ink coated 3D printed waveguides, the ink coated 3D printed waveguides was plated with copper and it is fully characterized. Additionally, this technique was also applied for the fabrication of a Single-Pole Double Throw switch to demonstrate the microfluidic concept further.

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  • Type of Item
  • Degree
    Master of Science
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    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.