Extra exam question E9B02
Subelement E9, ANTENNAS AND TRANSMISSION LINES· Group E9B
What is the front-to-back ratio of the antenna radiation pattern shown in Figure E9-1?
- A.36 dB
- B.14 dB
- C.24 dB
- D.18 dB (correct answer)
WhyThe antenna radiation pattern shown in Figure E9-1 has a front-to-back ratio of about 18 dB. Front-to-back ratio compares the main lobe's peak level (essentially 0 dB, reaching the outer ring at 0 degrees) to the peak level of the rear lobe near 180 degrees, which in this pattern falls to roughly the -18 dB ring, giving a front-to-back ratio of about 18 dB, answer D. The other figures don't match where the rear lobe's peak actually falls relative to the chart's labeled -3, -6, -12, and -24 dB rings.
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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