Baluns and Coax Connectors

What is a Balun?

Balun is an acronym for BALanced to UNbalanced. It describes a specific circuit behaviour in transmission lines, load or source. A lot of communication applications work with 2 terminal sources and loads. These include coaxial cables, open wires, and any system working underground as a conductor. 

How do Baluns work?

By using a balun, we can send AC signals of any kind through a pair of wires and make the required transmission to either end to provide a proper transfer of AC signals. Baluns are used to distribute the flow of AC signals and provide the necessary transformation between coaxial cables which have low impedance, and also balanced loads which have higher impedances. With RF frequencies, the use of balun is necessary to correct the function of antennas and transmitters. If not, there would be incorrect current flows, mismatches that can interfere with adjacent electronic equipment. 

Balun Terminology

Balun Ratio

A balun’s ratio is known as the sate of balanced to unbalanced. It has the ratio of 4 to 1 or 4:1 where a balun as 4 times the balanced impedance to unbalanced impedance.

Current Baluns

Current baluns allow terminal voltage to each output in regards to the ground. Current baluns are universal tools that work on unbalanced or balanced load really well. They have a common-mode of isolation and works great as broadband inverters. 

Voltage Baluns

Voltage baluns have strong force that puts output terminals to equal voltage. They introduce a phase shift between the output terminal and ground. If the impedance are imbalance or not equal, the feedline would radiate. 

Recommendation

We advise using current baluns vs voltage baluns whenever possible. Current baluns offer better balance and lesser loss, especially to 1:1 ratio that can tolerate load impedance and balance much better than its voltage counterpart.