Low-Profile Multiband Ferrite Antenna for Telematics Applications

Miniature low-profile multiband ferrite antennas were designed with various BaCo
_1.4
Zn
_0.6
Fe
₁₆
O
₂₇
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 (
$f_{1}$
), second (
$f_{2}$
), and third (
$f_{3}$
) 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
$f_{2}$
and
$f_{3}$
, while the gain at
$f_{1}$
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 BaCo
_1.4
Zn
_0.6
Fe
₁₆
O
₂₇
substrate loading allows antenna miniaturization with enhanced antenna performance.