Magnetic Materials in Transmission Line Transformers

This discussion is in regard to the required charactersitics of magnetic materials used in transmission line transformers. the K5 and Q1 ferrite cores operating at a 50:12.5 ohm using Ruthroff’s 1:4 design. These are in turn compared to an autotransformer using the Q1 core. As can be seen, the autotransformer is vastly inferior and the TLTs have similar efficiencies at this impedance level. Also the K5 transformer has a better low frequency response because of the higher permeability of this material.