2G051 Volume 2 URE Practice Exam

Impedance mismatch in RF systems means the load does not present the same impedance as the transmission line’s characteristic impedance. When this happens, part of the incident power is reflected back toward the source instead of being delivered to the load. That reflection creates standing waves along the line, raising the voltage and current at certain points and lowering the forward power that actually reaches the load. The practical consequences are reduced power transfer to the load and increased reflected power, which can stress the transmitter and other components and even cause damage if the reflections are large. This is why RF systems aim for good impedance matching and why return loss and SWR are important indicators. The other options don’t fit: impedance mismatch does affect RF performance (it doesn’t only affect DC circuits), it does not increase power transfer, and it does cause reflections instead of no effect.