Radiation resistance is the load that accounts for the power radiated by the antenna. Which option best describes its role?

Radiation resistance is the load that accounts for the power radiated by the antenna. Which option best describes its role?

• A. The resistance due to conduction losses in the wire
• B. The impedance of the feedline
• C. The resistance representing power radiated by the antenna
• D. The impedance seen at the source due to losses

Answer: (D)

Radiation resistance represents the part of the antenna’s input impedance that accounts for the power being radiated as electromagnetic waves. In practical terms, when you drive the antenna from a transmitter, the source “sees” an impedance at the feed point that determines how much of the input power is turned into radiation versus stored in reactive fields or lost as heat. This radiative part behaves like a real load—the radiation resistance—that sets how much power the antenna radiates for a given forward voltage or current. The total impedance seen by the source includes this radiation resistance plus any loss resistances from conductors or dielectrics. So, the role described as the impedance seen at the source due to the radiated power—the load that represents radiated energy—best captures how radiation resistance functions in the system.

Radiation resistance represents the part of the antenna’s input impedance that accounts for the power being radiated as electromagnetic waves. In practical terms, when you drive the antenna from a transmitter, the source “sees” an impedance at the feed point that determines how much of the input power is turned into radiation versus stored in reactive fields or lost as heat. This radiative part behaves like a real load—the radiation resistance—that sets how much power the antenna radiates for a given forward voltage or current. The total impedance seen by the source includes this radiation resistance plus any loss resistances from conductors or dielectrics. So, the role described as the impedance seen at the source due to the radiated power—the load that represents radiated energy—best captures how radiation resistance functions in the system.