Balun

A broad band Balun (a device which converts balanced mode electromagnetic field structures such as twin lead, to an unbalanced field structure such as coaxial cable) can be produced by taking the approach of gradually perturbing the field structure from one form to the other over a given distance. The concept is shown in figure 1 in which the transition from one field structure to another is carried out by cutting a wedge shape out of the cable. Any shape however can be removed from the cable commensurate with forming a match condition, as long as the transition is gradual.