Low frequency antenna

[0023]Rather than forming an antenna by wrapping a coil around a ceramic core, embodiments of the present invention reduce the size of such antennas by modifying certain material properties of the core. Specifically, in accordance with embodiments of the present invention, the permeability of the core is varied to achieve the desired result. By changing the permeability of the core, antenna parameters such as bandwidth and efficiency can be optimized or improved as the overall size is reduced.

[0024]The electromagnetic properties of materials, such as permeability and permittivity, can be understood by examination of propagation of waves. The wavelength of a wave propagating in through a material may change compared to free space propagation. In free space, the wavelength and frequency of a wave are related by:

c=fλ  (1)

[0025]where: c=speed of light (meters / second),

[0026]f=frequency in Hertz (1 / second), and

[0027]λ=wavelength (meters).

[0028]The following equation (derived directly fro