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Investigation of Magnetodielectric Resonator Antenna Including Gyroteropic Properties of Material

Naghdi, Behnam | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44421 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engieering
  6. Advisor(s): Rejaei, Behzad
  7. Abstract:
  8. So far, investigations have shown that open dielectric resonator antennas (DRAs) offer several advantages at microwave and millimeter wave frequencies. These advantages include small size, large impedance bandwidth, high radiation efficiency, ease of manufacturing and simple feed-coupling mechanisms (such as probe coupling, aperture coupling or proximity coupling to micro-strip lines). Most microwave ferrites have dielectric constants in the desirable range and they can be used in place of dielectric materials. Such ferrite resonator antennas (FRAs) offer a potential advantage in that their permeability tensor can be controlled by applying an external magnetic field. Up to now and by the application of a magnetic field, properties such as resonant frequency agility and polarization agility have been demonstrated experimentally. To our knowledge, analytical formulation of the FRA has been limited to introducing effective scalar permeability coefficients (instead of its original tensor) and then modeling it as a simple dielectric cavity. In this thesis we focus on the cylindrical shaped FRA which is magnetically saturated parallel to its axis and in addition to verifying the aforementioned approximation, we present other improved approximate models for the analyzing of the FRA and evaluate their outcomes. In our first approximation, we introduce an appropriate field distribution outside the resonator. An analytical formulation becomes possible and the accuracy of the results in predicting the resonant frequency has been compared with that of simple cavity model and it shows closer agreement with HFSS simulation results. A Comprehensive analysis of the FRA is performed by representing it as a terminated open wave guide. The mode coupling taking place at terminal plane is solved by variational methods to yield approximations to the antenna radiation pattern, efficiency, and radiation resistance.
  9. Keywords:
  10. Ferrite Resonator Antenna ; Dielectric Resonator Antenna ; Magnetic Dielectric Resonator Antenna ; Girotropic ; Giromagnetic

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