We demonstrate that electrically small ferrite antenna gain is significantly increased with a small dc magnetic field of compact Nd-Fe-B permanent magnet (9.5 × 4.6 × 1.5 mm3). The experimental magnetic tangent loss of the Ni-Mn-Co ferrite decreased by about 62%, which was from 0.509 with 0 Gauss to 0.192 with 750 Gauss. The antenna gain increased by 54% (from -10.58 to -4.81 dBi) when the magnetic field of 1600 Gauss was applied to the antenna. The ferrite antenna has the volume of 0.346 cm3 and shows omnidirectional patterns, which are suitable for hand-held mobile device applications.
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