• Author / Creator
    Gharaati Jahromi, Alireza
  • The purpose of this dissertation is to generate better solutions for the existing problems in the wireless communications and navigation systems by designing antennas with special characteristics such as circular polarization (CP), tilted beam, transparency, high gain, front to back ratio (FBR) and so forth, suitable for inclined surfaces especially in automotive applications.
    The first chapter provides an overview of the existing problem and a literature review about the previous studies, containing global navigation satellite system (GNSS), and especially global positioning systems (GPS) antennas and their characteristics, circularly polarized antennas and their advantages over the linearly polarized (LP) ones, antennas with tilted beams and some examples of such antennas, and also transparent antennas and different methods for reaching transparency. As the final part of this chapter, the aims of the current research and the thesis organization will be presented.
    Chapter 2 outlines a wideband circularly polarized antenna with a simple geometry, which covers the GNSS/GPS frequency bands. The antenna can be used for GNSS/GPS applications, but it lacks some characteristics that are needed for such applications, which are discussed both in the research aims and the conclusion of the chapter in more details.
    In chapter 3, a dual-band circularly polarized antenna is proposed for GNSS/GPS applications. The impedance and axial ratio (AR) bandwidths cover the entire GNSS/GPS bands. Although the performance of this antenna, especially in terms of front to back ratio (FBR), for GNSS/GPS applications has been improved compared to the one discussed in Chapter 2, still some additional characteristics such as tilted beam and transparency are needed to be added to these types of GNSS antennas for the end goal.
    In chapters 4 and 5, two novel wideband transparent circularly polarized antennas with tilted beams are proposed. The antennas cover the entire GNSS frequency bands in terms of both impedance and axial ratio bandwidths. The beams of the antennas are tilted for about 30 degrees, suitable to be mounted on the windshield of vehicles. A transparent reflector has been introduced and designed in order to be placed under the antenna on the glove compartment or dashboard of the vehicle in order to increase the FBR.

    Finally, in chapter 6, a brief discussion about possible future works is presented.
    Additional information and simulation results such as the characteristic mode analysis (CMA), conformability results on curved surfaces, tolerance, and upper and lower hemisphere energy division for proposed antennas of chapter 4 and 5 have been presented in the appendix.

  • Subjects / Keywords
  • Graduation date
    Fall 2021
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • 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.