What is attenuation in RF Cables?

The design and structure of an rf cable better equip it to propagate signals with minimal interference from external sources. RF cables also do not affect other electrical components within their vicinity. Although made to minimize noise and egression, attenuation occurs in some instances.

Attenuation of signal loss occurs when there is a reduction in the power transmitted in an rf cable. It doesn’t occur in only rf cables. Signals lose power as they pass through connectors, attenuators, equalizers, and other passive components. Factors such as leakages, resistance, and dielectric loss can cause a reduction in signal strength or power. In this blog, we will look at some causes of attenuation and how to remedy them.

Factors that affect or cause signal loss.

Length: Generally, the longer the rf cable, the more the signal loss experienced. The signal loss also increases as the frequency increases ( technically speaking, the square root of the frequency). The quality of the cable also plays a role in signal loss per unit length.

Resistive losses.

No material has 100% conductivity-This means that even a highly conductive material such as copper still has some resistance. When signals flow through the conductive core, some energy will be lost due to heat. Electric signals tend to travel near the surface of the wire or solid conductor. As the frequency of the signal increases, so does the skin effect and the amount of ‘available’ metal to conduct electricity. The increased skin effect and resistance lead to greater attenuation.

Leakages from inadequate shielding.

Rf cable manufacturing and assembly involves using concentric layers of conductors and insulators to make a transmission line. The shield and the core conductor both generate electrical and magnetic fields. However, the signals flow in a different direction, and the fields cancel out. Sometimes, the signal can leak through the shield. This usually occurs when there are flaws or damages in the shield.

Damages can occur due to excessive bending or compromise to the surface by abrasion, rodent attack, or oxidation. Rf cable assembly manufacturers make braided shields to add flexibility, but they may be more susceptible to leakages than solid metal sheaths.

Dielectric losses.

Sometimes, loss occurs when the dielectric material absorbs some of the electromagnetic energy produced by both conductors. This form of loss increases directly with the frequency.

Mismatch loss.

Mismatch occurs when there is uneven impedance in the cable. Excessive bending, damaging or deformation can cause the impedance to vary. Mismatch loss refers to how much power is attenuated due to the reflection of the signal.