What are Non-Magnetic RF Connectors?

When we talk about RF components, the connectors are usually assumed to be fairly simple and uncomplicated. There are multiple types of connectors such as SMA, N-Type, 2.92 mm, BNC, etc., and these regular connectors are sufficient for most of RF requirements. However, there are some special applications that require special connectors with unique properties. Non-Magnetic Connectors are one of them.

Non-Magnetic Connectors are ideal for applications that experience strong magnetic fields which can cause interference or introduce errors. One of the primary uses of Non-Magnetic Connectors is in medical applications, specially Magnetic Resonance Imaging (MRI) equipment. MRI machines/scanners are widely used in radiology to generate images of the anatomy and physiological processes of the body, and these scanners use strong magnetic fields (0.3 – 3+ Tesla) to generate the images. The problem with normal RF connectors is when they experience a strong magnetic field, signals gets distorted and lose their spatial resolution and the signal-to-noise ratio (SNR) also takes a hit.

Magnetic Resonance Imaging (MRI) Machine

Ideally, the connectors should be transparent or invisible relative the magnetic field, meaning their relative permittivity should be 1. To achieve this and provide electromagnetic immunity, non-magnetic RF connectors are made from diamagnetic materials and plating. Examples of diamagnetic materials are Gold, Bismuth, Mercury, Copper, etc. Diamagnetism lowers the material’s response to the magnetic field present, which helps in reducing interference significantly. These diamagnetic materials introduce field distortions but they are very small and can be easily neglected.

MRI Images Comparison – First Image (Left) shows a low spatial resolution, low SNR result using 1.5 Tesla magnetic field.
Second Image (Right) shows a high spatial resolution, high SNR result using 3 Tesla magnetic field.

Apart from medical applications, non-magnetic RF connectors are also used in space applications. It is no hidden fact that space is filled with EM waves and the extra electromagnetic immunity can help in increasing accuracy, mainly in scientific research missions.

With the increasing requirement for non-magnetic RF connectors in medical, space and other applications, various manufacturers have created dedicated segments exclusively for such connectors. Radiall, Samtec, SV Microwave are some of the leading companies that manufacture non-magnetic connectors.

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