Balun vs Antenna Tuner

This page on Balun vs Antenna Tuner describes basics of balun and antenna tuner as impedance matching devices.

There are various impedance matching techniques. These are aimed at connecting two lines of different impedances to avoid any loss. The popular among them are stub or Q-section of length equal to λ/4.
ZQ = (ZL * ZO)0.5
Where, ZO is the source line or input impedance
ZL is the load line or output impedance
ZQ is the characteristic impedance of stub or Q section.


The electronic device Balun is the short form of Balanced-Unbalanced transformer. It is type of transformer used to match two different impedances. Most baluns are made of a ferrite core (either a toroid or a rod ) and copper wire windings.

Baluns usually will have very wide bandwidth and hence they are independent of frequency of operation. Baluns can be designed to produce different impedance matching ratios such as 4:1 or 9:1 or 16:1 etc.

Fig.1 Balun

Baluns can be made using coaxial cable. It will have half wavelength and will be connected between feed line and the antenna. It is used to convert 300 Ohm antenna to 75 Ohm load and vice versa.

Antenna Tuner

The Antenna Tuner is also used when balun can not do the job. It is made of inductors and capacitors in various different combinations. The most common antenna tuner configurations are of L, T and Pi type.

The values of inductors and capacitors are tuned to adjust impedance matching as required based on SWR requirement.

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