Extra exam question E9F04
Subelement E9, ANTENNAS AND TRANSMISSION LINES· Group E9F
What impedance does a 1/2-wavelength transmission line present to an RF generator when the line is shorted at the far end?
- A.Very high impedance
- B.Very low impedance (correct answer)
- C.The same as the characteristic impedance of the line
- D.The same as the output impedance of the RF generator
WhyA 1/2-wavelength transmission line shorted at the far end presents a very low impedance to an RF generator. A half-wavelength transmission line repeats whatever impedance is at its far end back at its input, so a line shorted at the far end (very low impedance) presents that same very low impedance back to the generator, answer B. It doesn't present very high impedance, doesn't present the line's characteristic impedance regardless of termination, and doesn't simply mirror the generator's own output impedance, a half-wave line specifically repeats the actual far-end termination.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2024-2028 NCVEC Element 4 pool (public domain); the explanation above is original writing, see our methodology.
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