Miniaturized Broadband Ferrite T-DMB Antenna for Mobile-Phone Applications

Abstract

Miniaturized 0.026 ¿ Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Z hexaferrite and Ni-Mn-Co spinel ferrite T-DMB antennas were fabricated and characterized for antenna performance. The Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Z hexaferrites were prepared with two different processes that are water quenching and air cooling. The water quenched Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Z hexaferrite antenna shows -6.5 dB of 3-D average gain at 190 MHz and 37 MHz of bandwidth at -10 dB. A magnetic tangent loss of water-quenched Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Z hexaferrite was lower than that of air-cooled Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Z hexaferrite. Compared to the hexaferrite antennas, the Ni-Mn-Co ferrite antenna shows higher frequency performance. Its gain and bandwidth were measured to be -5.83 dB at 215 MHz and 41 MHz, respectively. Omnidirectional gain pattern was observed from all fabricated ferrite antennas.