What is the primary benefit of impedance matching among transmitter, feed line, and antenna?

• A. Maximizes power transfer and minimizes reflections
• B. Increases RF noise immunity
• C. Eliminates the need for a tuner
• D. Doubles the antenna gain

Answer: (A)

Impedance matching ensures the transmitter, feed line, and antenna present the same impedance to the system so RF power is transferred efficiently. When the load impedance equals the source impedance (and the line’s characteristic impedance), the transmitter delivers maximum power to the antenna and there are minimal reflections back toward the transmitter. Mismatches cause part of the power to reflect, creating standing waves on the line, which raises voltage and current at the transmitter, reduces radiated power, and can stress or damage the transmitter. A matching network helps the antenna (or line) present the correct impedance to the transmitter across the operating band, keeping the energy flowing into radiation rather than bouncing back. This focus on matching boosts power transfer and protects equipment; it does not inherently increase antenna gain or automatically improve RF noise immunity.