Miniaturized Antennas With Reduced Hand Effects in Mobile Phones Using Magneto-Dielectric Material

In this letter, magneto-dielectric (MD) material is proposed to reduce the antenna volume without significant performance degradation and mitigate the efficiency decrease by the human hand. The MD ceramic, which has small magnetic loss tangent around 0.1 or less at 2 GHz, is developed using hexagonal ferrites. This ceramic material is mixed with polymers to form the MD composites, which can be easily applied to the complex-shaped substrates of mobile antennas. Inverted-F antennas (IFAs) on the composites are simulated for studying of the antenna miniaturization and hand effects. Mobile antennas using the composites are manufactured by injection molding and plating processes. Then, the radiation efficiencies are measured with and without the hand phantom. The test results show that the MD composites are useful for miniaturizing antennas and reducing hand effects in the mobile phones.