Return Loss Degradation

Signal Reflection

Impedance matching is required to ensure that the maximum amount of signal power is transmitted from the source to the load. When a signal encounters a change in impedance, a portion of the wave is reflected, which reduces the return loss. This can be caused by routing errors, vias, or defects in the circuit board laminate.

Impedance Discontinuity

Severe reductions in return loss can cause multiple reflections to travel back and forth along the transmission line, creating noise that distorts the received signal. This distortion degrades the eye diagram, leading to increased jitter and higher bit error rates in digital systems. In RF systems, it reduces the overall efficiency of the transmitter and can damage sensitive components.

System Integrity

Designers use time-domain reflectometry to locate the sources of reflections and optimize the trace geometry to restore return loss to acceptable levels. This process is essential for maintaining signal path quality.