Support decoupled half-wave aerial for mobile equipment - uses quarter wavelength rod with ferromagnetic decoupling section serving as quarter wavelength aerial

摘要

The antenna consisting of two radiation parts esp. for half wave aerials has a decoupling section against the aerial support such as a vehicle or a portable communication equipment and is for a frequency range of 80-500 MHz, pref. 146-174 MHz. The feeding point of the aerial is transferred from the middle of the aerial towards the support and is connected to the upper end of a short decoupling section of ferromagnetic material with the dielectrical constant approximately corresponding to the permeability. The length of the decoupling section is approximately equal to a quarter wavelength divided by the square root of the product of dielectrical constant and permeability. The ferromagnetic material may be either ferrite or carbonyl iron or a combination of both and may be in the form of a drilled out cylinder. The decoupling section consists of a coaxial cable section with threaded-on single hole cores of one or different ferromagnetic materials.