科研之友
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摘要
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 degrees with an operation frequency, which can be tuned in the 4-4.5 GHz range by varying the magnetic bias field from 50 to 35 000 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.
- 出版日期2014-3
