Return loss

Return loss, also known as return loss, plays a crucial role in characterising the signal quality in metallic cables, especially in high-frequency applications. This concept refers to the ratio between the injected signal energy and the backscattered energy in the cable.

Inhomogeneities within the cable or in the RF connectors can lead to reflections where some of the signal energy is scattered back into the cable instead of travelling towards the receiver. This backscatter can be caused by various factors, including impedance differences, interference or interruptions in the cable.

The return loss is expressed as the ratio of the reflected signal to the injected signal level. A higher value for return loss means a lower amount of backscattered energy compared to the injected energy and therefore indicates efficient signal transmission.

Return loss is usually measured in decibels (dB) and is closely related to the voltage standing wave ratio (VSWR). The VSWR is a measure of the match between the line and the load and indicates how well the line transmits the signal energy to the load without reflections occurring. A low VSWR is typically associated with a high return loss and therefore indicates good matching and minimal signal losses.

In high-frequency technology, return loss is an important parameter for evaluating the signal quality and performance of transmission systems. An in-depth understanding of this concept is crucial for the development and optimisation of communication systems, particularly in areas such as telecommunications, radio technology and data transmission.