Everything to Know About the Winding Process of RF Coils

An RF or radiofrequency coil is an electromagnetic micro-coil that comprises a core and the winding of an electrically conductive ultra-fine wire around the core. Due to multiple essential applications, RF coils are substantially valuable in the medical and electronics field. A major example of the application of RF coils is observed in MRI machines. In this article, we will discuss the characteristics, applications, and manufacturing process of the RF coils.

RF Coils Characteristics:

The most crucial characteristics of RF coils are-

• The winding process of RF coils involves the twisting of an insulated wire around a pin or core. This wire has to be able to conduct electricity in order to produce a magnetic field. However, the manufacturing process of these coils is responsible for increasing the magnetic field’s intensity. 
• The magnetic field around the coil looks like a bar magnet and it also has a north and south pole. The shape of the RF coils can differ based on the demand and application area and different shapes are also responsible for different strengths of the magnetic field.
• The strength of the magnetic field raises with the inclusion of the additional layers around the core. 

Applications of Radiofrequency Coils:

In a variety of industries, you can observe the applications of RF coils. Nevertheless, the use of RF coils is majorly visible in electronics and medical sensors. Magnetic Resonance Imaging or MRI machine is the most crucial example of RF coil application. RF coils help to transmit and receive signals in MRI machines. 

How to Manufacture RF Coils?

RF coil manufacturing process or winding process includes multiple activities. Let’s understand the activities step by step.

• First of all, designers focus on preparing the initial designs of the RF coils using simulation and modeling tools. These tools are really essential particularly when it comes to manufacturing the coils to apply in the MRI machines. COMSOL Multiphysics is an outstanding tool from Sweden that effectively helps the designers to design the RF coils. If you are going for Orthocyclic winding, you should take an interactive approach to deal with the space crisis. Therefore, before you design a coil, you have to calculate and gather information about the desired number of windings, the insulated wire’s cross-sectional area, and the available space for the insulated core.
• After designing, the manufacturers need to determine the type of the core and its material on the basis of the device’s operating frequency and many other factors. Most manufacturers prefer to use powdered iron or ferrite cores.
• The third step is about the RF coil winding process where an insulated copper wire is wound or twisted around a core or pin. In order to decide the number of turns, manufacturers consider the inductance and properties of the core material. For instance, if a larger inductance is essential, the manufacturers increase the number of turns. However, in today’s world, the entire manufacturing process is carried out by automated machinery. The orthocyclic winding method is the most appropriate method to produce tight structure for the RF coils.
• Finally, manufacturers need to check and validate the finished coils.