rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Beam-scanning reflectarray enabled by fluidic networks
  name:
    name part: Long, Stephen.
    role:
      role term: creator
  name:
    name part: Huff, Gregory H.
    role:
      role term: thesis advisor.
  type of resource: text
  genre: bibliography
  origin info:
    place:
      place term: txu
    date issued: 2012
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: remote
    extent: 1 online resource.
  abstract: This work presents the design, theory, and measurement of a phase-reconfigurable reflectarray (RA) element for beamforming applications enabled by fluidic networks and colloidal dispersions. The element is a linearly polarized microstrip patch antenna loaded with a Coaxial Stub Microfluidic Impedance Transformer (COSMIX). Specifically, adjusting the concentration of highly dielectric particulate in the dispersion provides localized permittivity manipulation within the COSMIX. This results in variable impedance load on the patch and ultimately continuous, low-loss phase control of a signal reflected from the patch. Different aspects of design, modeling, and measurement are discussed for a proof-of-concept prototype and three further iterations. Initial measurements with manual injections of materials into a fabricated proof-of-concept demonstrate up to 200 degrees of phase shift and a return loss of less than 1.2 dB at the operating frequency of 3 GHz. The next design iteration addresses fabrication challenges as well the general cumbersomeness of the proof-of-concept by replacing the static material delivery system with a dynamic closed-loop fluidic network. It also makes use of a design procedure to maximize the phase sensitivity. Measurements demonstrate progressive phase shifts through dilution of the system reservoir; however, the initial measurements with this system are not in line with simulated predictions. Investigations suggest the primary culprit to be inaccurate material data. The dielectric constant of the particulate (colloidal BSTO) was overrated and the loss tangent of the fluid medium (a silicone-based oil) was underrated. After accounting for these issues the measurement a second measurement with the system demonstrates 270 degrees of phase shift with return loss of 9 dB. The next design iteration examines a trade-off between phase sensitivity and reduced losses. The design also features modifications to the fluidic system to allow for layered fabr…
  note: by Stephen Long.
  note: "Major Subject: Electrical Engineering"
  note: Electronic resource.
  note: Doctor of Philosophy Texas A&M University 2011 http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10592
  note: Includes bibliographical references.
  note: Text (Dissertation)
  subject:
    topic: Major Electrical Engineering
  subject:
    topic: dispersion
  subject:
    topic: BSTO
  subject:
    topic: volume fraction
  subject:
    topic: reflectarray
  subject:
    topic: COSMIX
  identifier: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10592
  record info:
    record content source: TXA
    record creation date: 121012
    record change date: 20150922123832.0
    record identifier: in00002761250