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A circularly polarized antenna based on the unidirectional resonant modes of a ferrite disk

Ghalibafan, J ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1109/TMAG.2013.2283655
  3. Abstract:
  4. We propose a circularly polarized antenna with a wide axial ratio (AR) beamwidth that consists of a normally magnetized ferrite disk mounted on a ground plane. The device uses the resonant modes of the disk, which rotate only in the clockwise or counter-clockwise sense in the frequency range where the effective permeability of ferrite is negative. A semianalytical model is derived for the antenna fed by a single, conventional current probe and is validated numerically by finite element method. For a yttrium iron garnet disk with the radius and height of 5 and 1 mm, respectively, the results show a 3 dB AR beamwidth of 90° with an operation frequency, which can be tuned in the 4-4.5 GHz range by varying the magnetic bias field from 50 to 35000 A/m. Simulations show that higher AR beamwidths are achievable using finite ground conductors. Compared with previous papers, the fabrication requirements on this structure are not critical, which enhances its potential applicability
  5. Keywords:
  6. Circular polarization (CP) ; Ferrite loaded antenna ; Tunable antenna ; Wide-angle axial ratio (AR) ; Antenna feeders ; Conductors (electric) ; Finite element analysis ; Garnets ; Microwave antennas ; Permeability ; Probes
  7. Source: IEEE Transactions on Magnetics ; Volume 50, Issue 3 , 26 September 2013 , Pages 88-95
  8. URL: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6612634