Low-Profile Multiband Ferrite Antenna for Telematics Applications.

Miniature low-profile multiband ferrite antennas were designed with various BaCo1.4Zn0.6Fe16O27 hexaferrite loading configurations and fabricated for telematics applications. Experimental permeability ( \mu ^\prime ) of 2.0, permittivity ( \varepsilon ^\prime ) of 7.3, magnetic loss tangent (tan \delta \mu ) of 0.035, and dielectric loss tangent (tan \delta \varepsilon ) of 0.005 at 1 GHz were used for antenna performance simulations. It is observed that a hollow rectangular ferrite substrate loading shows simulated maximum ripple levels ( \Delta = E\theta \\max -E\theta \\min ) of 2.2, 3.0, and 1.9 dB at the first ( f1 ), second ( f2 ), and third ( f3 ) resonant frequencies, respectively, implying wider coverage than other loading configurations. Miniaturization factor is greater than that of air-core antenna, and the impedance matching and bandwidth are improved with the ferrite loading. Higher gain of the ferrite-loaded antenna than the air-core antenna was observed at f2 and f3 , while the gain at f1 remains almost the same. Moreover, the vertical component E\theta is greater than the horizontal component E\phi , showing the vertically polarized operation of the antenna. Based on the measured and simulated results, it is concluded that the BaCo1.4Zn0.6Fe16O27 substrate loading allows antenna miniaturization with enhanced antenna performance. [ABSTRACT FROM PUBLISHER]