Circulators

A circulator is a box-shaped ferrite device that has three or four ports and allows energy from one port to transfer to the next port in line. Circulators are usually used with radio signals but can also be used with microwaves, light, and other electromagnetic waves. This means that a radio signal that is being emitted from a transmitter in port one travels to an antenna in port two and then to a receiver in port three. Any residual energy in the receiver is eventually transferred back to port one. This is what makes a circulator such an efficient device.

How a Circulator Works
A circulator is almost completely made of ferrite, a type of magnetic material. A permanent magnet is placed inside the circulator in order to drive the energy into a rotational motion. Transmitters, receivers, and antennas can all be placed in any port and circulators can drive the energy either clockwise or counterclockwise. In fact, a device known as a switchable circulator uses a high current electricity pulse to switch the circulator between clockwise and counterclockwise on demand.

Applications
Circulators are most commonly used to produce highly efficient transceivers that are used in wireless computer networks, radio broadcasting, RADAR, and astronomy. They are also used for heating, cooling, immersion, and viscosity bathing. Circulators are often used in systems that handle large amounts of electricity due to their ability to process up to several kilowatts.

Advantages
Circulators have low energy loss levels and are capable of handling large amounts of power. They also route energy from a transmitter to an antenna while it is transmitting, and from an antenna to a receiver while it is receiving. This is critical in certain situations, such as RADAR, as the same antenna handles incoming and outgoing signals.

Disadvantages
While they are advantageous, circulators also have several disadvantages. Circulators are more expensive than other types of microelectronic devices as they must be hand crafted and are almost entirely made from magnetic materials. Also, circulators generally produce low bandwidth signals and can only be used with electromagnetic waves.