subject: An Introduction to Circulators and Their Uses [print this page] An Introduction to Circulators and Their Uses
Circulators are the passive devices that contain three or more ports to transfer the power from one port to another in an organized order. It means the power that enters from port n will leave from port n+1. Thus, circulators are non-reciprocal.
The circulators are the most vital component used in radio frequencies (rf) and microwave equipments. They mainly fall into two classes, which are as follows:
3- port circulator based on Y shaped junction
4-port waveguide circulator based on Faraday rotation
In the 3-port junction, if waves coming from different path cross each other, the waves cancel each other near the magnetized material. Whereas, in case of the 4-port faraday rotation, waves propagate inside the magnetized material.
Example of a Three Port Circulator
The three-port circulator is a Y-junction shaped circulator in which the power entering from the port 1 will leave from port 2, and port 3 remains decoupled. Similarly, the power entering from port 2 will leave from port 3 and port 1 remains decoupled.
Now, you know that the power that enters port 3 in a three-port circulator will leave from port 1 and port 2 remains decoupled.
On major benefit of circulators is that they can be set to move in either direction, clockwise or anticlockwise. These circulators are called as Switchable Circulators.
What are the Uses of Circulators?
Circulators are used in various devices that require low frequency (LF), very high frequency (VHF), ultra high frequency (UHF) and in optical networks that require light. These components handle the flow of very high power in various devices.
Some of the examples are listed as below:
A water load circulator is used to absorb high power signals and maintain the reasonable power. The reasonable power attain is finally pass to the receiver or the measurement port.
Circulators, used in radar applications, help in routing the incoming and outgoing signals between the antenna, the transmitter and the receiver.
Radio frequency circulators, used in optical circuits, consist of ferrite material that when magnetized produce a continuous magnetic flux through waveguide.
In addition to the afore-mentioned uses, circulators are also used in broadcast and TV transmitters, air traffic control, military equipments, car telephone systems and microwave heating applications.
Why are Circulators so Expensive?
Circulators are expensive because they are manually assembled, finely tuned and efficiently tested before they are used.
