Loizou, Loizos (2010-12). A Non-Pyramidal Rectangular-to-Trough Waveguide Transition and Pattern Reconfigurable Trough Waveguide Antenna. Master's Thesis. Thesis uri icon

abstract

  • Trough waveguides (TWG) have been utilized in a variety of radio frequency (RF) and other related applications including radar, the treatment of hypothermia and in the generation of plasmas. Perturbing the guided wave in these structures with blocks, rods, dielectrics, and other structures can create reconfigurable periodic line sources. These trough waveguide antennas (TWA) are then capable of providing both fixedfrequency and frequency-dependent beam steering. This was originally performed using electro-mechanical "cam-and-gear" mechanisms. Previous work related to the excitation of TWG and the performance of TWA topologies are limited when compared to more common antenna designs, yet they possess many desirable features that can be exploited in a modern system. This thesis will examines an S-band rectangular-to-trough waveguide transition and trough guide antenna that has been designed for broadband reconfigurable antenna applications considering as well the airflow characteristics for sensing applications. The design, fabrication, and electromagnetic performance (mode conversion, impedance matching, and antenna performance) are discussed, including the use of metallic cantilever perturbations placed along the troughguide sidewalls that are designed to provide improved impedance matching when steering the beam from the backward quadrant through broadside, towards the forward quadrant. Impedance matching techniques such as use of circular holes at the edge of each actuated cantilever are used to reduce power reflections and provide a low voltage standing wave ratio (VSWR) along the S-band. Finite element simulations will provide a demonstration of the airflow and turbulence characteristics throughout the entire structure, where the metallic cantilevers are used to manipulate the flow of air, to distribute it across the surfaces of the structure better and improve its potential for sensing operations.
  • Trough waveguides (TWG) have been utilized in a variety of radio frequency
    (RF) and other related applications including radar, the treatment of hypothermia and in
    the generation of plasmas. Perturbing the guided wave in these structures with blocks,
    rods, dielectrics, and other structures can create reconfigurable periodic line sources.
    These trough waveguide antennas (TWA) are then capable of providing both fixedfrequency
    and frequency-dependent beam steering. This was originally performed using
    electro-mechanical "cam-and-gear" mechanisms. Previous work related to the excitation
    of TWG and the performance of TWA topologies are limited when compared to more
    common antenna designs, yet they possess many desirable features that can be exploited
    in a modern system.
    This thesis will examines an S-band rectangular-to-trough waveguide transition
    and trough guide antenna that has been designed for broadband reconfigurable antenna
    applications considering as well the airflow characteristics for sensing applications. The
    design, fabrication, and electromagnetic performance (mode conversion, impedance matching, and antenna performance) are discussed, including the use of metallic
    cantilever perturbations placed along the troughguide sidewalls that are designed to
    provide improved impedance matching when steering the beam from the backward
    quadrant through broadside, towards the forward quadrant. Impedance matching
    techniques such as use of circular holes at the edge of each actuated cantilever are used
    to reduce power reflections and provide a low voltage standing wave ratio (VSWR)
    along the S-band. Finite element simulations will provide a demonstration of the airflow
    and turbulence characteristics throughout the entire structure, where the metallic
    cantilevers are used to manipulate the flow of air, to distribute it across the surfaces of
    the structure better and improve its potential for sensing operations.

publication date

  • December 2010