If anyone is interested in a somewhat esoteric but fascinating topic, you need to get a copy of the now classic "Transmission Line Transformers" by Jerry Sevick, W2FMI.
For those unfamiliar with the topic, transmission line transformers function rather differently from "normal" transformers, in that the coupling between windings is as much capacitive as it is inductive. For many radio frequency applications, this can result in much greater efficiency than conventional transformers.
With a few exceptions, Tramsmission Line transformers only have "perfect square" impedance ratios...e.g., 1:1, 4:1, 9:1, 16:1, 25:1, etc. Generally, this is a small tradeoff when it comes to the increased efficiency and bandwidth available. Most modern R.F. power circuits employ transmission line transformers somewhere.
Although air-core transmission line transformers are possible, most modern applications uses high permeability ferrite cores for physical compactness and wide bandwidth.
Be glad to discuss these gems with anyone. Just happen to be in the midst of a private R/D project with lots of them.
eric
For those unfamiliar with the topic, transmission line transformers function rather differently from "normal" transformers, in that the coupling between windings is as much capacitive as it is inductive. For many radio frequency applications, this can result in much greater efficiency than conventional transformers.
With a few exceptions, Tramsmission Line transformers only have "perfect square" impedance ratios...e.g., 1:1, 4:1, 9:1, 16:1, 25:1, etc. Generally, this is a small tradeoff when it comes to the increased efficiency and bandwidth available. Most modern R.F. power circuits employ transmission line transformers somewhere.
Although air-core transmission line transformers are possible, most modern applications uses high permeability ferrite cores for physical compactness and wide bandwidth.
Be glad to discuss these gems with anyone. Just happen to be in the midst of a private R/D project with lots of them.
eric
