Extra exam question E9B01
Subelement E9, ANTENNAS AND TRANSMISSION LINES· Group E9B
What is the 3 dB beamwidth of the antenna radiation pattern shown in Figure E9-1?
- A.75 degrees
- B.50 degrees (correct answer)
- C.25 degrees
- D.30 degrees
WhyThe antenna radiation pattern shown in Figure E9-1 has a 3 dB beamwidth of about 50 degrees. In Figure E9-1, the main lobe (pointing toward 0 degrees) crosses the pattern's -3 dB ring at roughly plus and minus 25 degrees off boresight, giving a total 3 dB beamwidth of about 50 degrees, answer B. The narrower 25 and 30 degree figures describe only the half-angle on one side rather than the full beamwidth, and 75 degrees is wider than where the pattern actually crosses the -3 dB ring.
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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