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

Miniaturized 0.026 ¿ Co2Z hexaferrite and Ni-Mn-Co spinel ferrite T-DMB antennas were fabricated and characterized for antenna performance. The Co2Z hexaferrites were prepared with two different processes that are water quenching and air cooling. The water quenched Co2Z 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 Co2Z hexaferrite was lower than that of air-cooled Co2Z 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.