3D Micro-fabricated Millimeter-wave Devices: Waveguides and Waveguide Switches

• Author / Creator

  Vahabisani,Nahid

• Rectangular waveguides (RWG) are highly desirable in millimeter-wave applications due to their excellent RF performance and their low signal loss. As the result, waveguide devices such as waveguide switches have been widely used for the majority of high-frequency low-loss applications during the past few decades. As the electronic industry progresses towards integration and small form factors, there is a need to integrate waveguides on wafer level as well. By the advancement of MEMS and micro-fabrication, miniaturization and micro-fabrication techniques are being studied to provide an answer to high demands of compact, light weight and reliable waveguide structures which can be potentially realized in wafer-level. In this thesis, a new category of waveguides and MEMS waveguide devices are introduced and prototypes such as filled and hollow waveguides and MEMS waveguide switches have been realized. A novel monolithic micro-fabrication technology is developed which enables the successful realization of monolithic wafer-level waveguide structures and their integration with MEMS technology. The dielectric-filled waveguides can be used for lower frequency applications where they offer smaller size comparing to their air-filled counterparts. The RF performance of the presented waveguide in this work only depends on the RF properties of the filling dielectric not the carrier substrate (as in the case of Substrate Integrated Waveguides), which makes it ideal for silicon micro-fabrication technology. The simulated and measured performance of the proposed dielectric-filled waveguide shows improvement over the previously reported on-wafer dielectric-filled waveguides. Variety of on-wafer waveguide structures such as bends, junctions and turns are also realized by this technique. Air-filled monolithic wafer-level rectangular waveguides are also presented in this thesis. The proposed waveguides are monolithically integrated with planar transmission lines which inherit a superior advantage over their counterparts and provide integration options between planar and 3D structures on the same substrate. A metalized post is employed to couple the signal from the CPW line to the waveguide. Unlike the previous designs that are mostly based on capacitive coupling, the proposed CPW to waveguide transition is based on inductive coupling which simplifies the fabrication requirements and improves the performance. The simulated and measured results reveal that extremely low-loss waveguides for millimeter-wave applications are realizable by this technique. In addition, we have monolithically integrated MEMS with waveguide structures and for the first time developed monolithic millimeter-wave MEMS waveguide switch. This introduces an entirely new category of on-wafer RF MEMS switches and can pave the way for other configurations such as single-pole double-throw(SPDT), C-type, and R-type waveguide switches and switch matrices.

• Subjects / Keywords

  • MEMS waveguides
  • Waveguide Switches
  • Monolithic devices

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3NG4GZ7T

• License

  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.