I have a balanced balun with 1:1 impedance ratio, while I need 1:2. Is it possible to change the ratio by including some resistors/inductors to match 100 Ohm output?
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2 Answers
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Assuming you are driving a 100 ohm transmission line that will work but it is going to cost you half of your power.
You would be far better off getting a 1:2 balun.
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Using reactive components, it is possible to match any arbitrary impedances at a given frequency. However, at other frequencies, the impedances will not match.
Generally, there is no power benefit accrued to matching impedances by adding a resistor, as the resistor will dissipate power.
The impedance ratio of a transformer type balun is the turns ratio squared. Since transformer type baluns generally have a small number of turns, the available impedance ratios are limited. An impedance ratio of 9:4 is not exactly 2:1 but it may be adequate for your use case. If it is not close enough, and you can live with more turns, impedance ratios of 16:9, and 49:25 are feasible.
answered Mar 5 at 14:37