Low-frequency antenna

摘要

An antenna comprises a feed port connected to a conductive element 11 which is at least partially encapsulated. The encapsulation 12 includes: a core part 13, formed with a material with a constant permeability, permittivity and conductivity, which is adjacent to the antenna conductor 11 and an external encapsulation part 14, formed with a material where at least two of the: permeability, permittivity and conductivity, increase in value in a direction extending from the surface of the core part 13 to the outer periphery of the external part 14. The ratio of the permeability and permittivity of the external encapsulation part 14 is constant and is equal to that of the environment local to the antenna. Also disclosed is an antenna which comprises a feed port connected to a conductive element which is at least partially encapsulated and where the encapsulation includes alternating first and second areas, wherein each of the first areas has higher values of permeability, permittivity and conductivity to those of the second areas. The compact antenna may operate at low frequencies and/or in arrays and be used in many applications such as: remote power transmission systems and operations requiring good signal penetration characteristics.