Kihong Min

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.

Reducing effects of hand phantom on mobile antennas using magneto-dielectric material

In this paper, a practical application of the magneto-dielectric (MD) materials to the mobile handset antennas is presented. The polymer MD composites with the property of low magnetic loss (tan δm <; 0.1) up to 2 GHz are developed using hexagonal ferrites and polymer matrices. The MD composites are applied to manufacture an actual antenna substrate for a mobile handset. Experimental results show that the MD composite antenna is advantageous for an antenna miniaturization and deterioration of performance by a hand phantom.