US Patent 9070978 Dipole antenna for safety helmets

Substantially-linear dipole antenna for safety helmets, of the type comprising two conductive branches arranged to be electrically connected, at one of their ends, to respective radio equipment, the two conductive branches being disposed substantially aligned. The two conductive branches have a length essentially equal to ¼ of the expected operative wavelength of the radio equipment. The dipole antenna further comprises at least two conductive arms, each having a length essentially equal to ½ of said operative wavelength, each of which is electrically connected respectively to the free end of both of the two conductive branches, both having a length essentially equal to ¼ of the operative wavelength.