An electrical connection between a balanced circuit, such as a radio receiver and an unbalanced circuit, such as an antenna requires a balun. In a small electronic device such as a radiotelephone, a traditional balun is impractical because of the physical constraints. The balun function is performed...http://www.google.fr/patents/US5565881?utm_source=gb-gplus-shareBrevet US5565881 - Balun apparatus including impedance transformer having transformation length
Balun apparatus including impedance transformer having transformation length
