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Extra-Study/pages/E9B.md
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2025-05-01 15:49:18 -05:00

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E9B Antenna patterns and designs: azimuth and elevation patterns; gain as a function of pattern; antenna modeling

  • E9B01 (B) What is the 3 dB beamwidth of the antenna radiation pattern shown in Figure E9-1? #card
    • A. 75 degrees
    • B. 50 degrees
    • C. 25 degrees
    • D. 30 degrees
  • E9B02 (D) What is the front-to-back ratio of the antenna radiation pattern shown in Figure E9-1? #card
  • E9B03 (D) What is the front-to-side ratio of the antenna radiation pattern shown in Figure E9-1? #card
  • E9B04 (B) What is the front-to-back ratio of the radiation pattern shown in Figure E9‑2? #card
  • E9B05 (A) What type of antenna pattern is shown in Figure E9-2? #card
    • A. Elevation
    • B. Azimuth
    • C. Near field
    • D. Polarization
  • E9B06 (C) What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2? #card
    • A. 45 degrees
    • B. 75 degrees
    • C. 7.5 degrees
    • D. 25 degrees
  • E9B07 (C) What is the difference in radiated power between a lossless antenna with gain and an isotropic radiator driven by the same power? #card
    • A. The power radiated from the directional antenna is increased by the gain of the antenna
    • B. The power radiated from the directional antenna is stronger by its front-to-back ratio
    • C. They are the same
    • D. The power radiated from the isotropic radiator is 2.15 dB greater than that from the directional antenna
  • E9B08 (D) What is the far field of an antenna? #card
    • A. The region of the ionosphere where radiated power is not refracted
    • B. The region where radiated power dissipates over a specified time period
    • C. The region where radiated field strengths are constant
    • D. The region where the shape of the radiation pattern no longer varies with distance
  • E9B09 (B) What type of analysis is commonly used for modeling antennas? #card
    • A. Graphical analysis
    • B. Method of Moments
    • C. Mutual impedance analysis
    • D. Calculus differentiation with respect to physical properties
  • E9B10 (A) What is the principle of a Method of Moments analysis? #card
    • A. A wire is modeled as a series of segments, each having a uniform value of current
    • B. A wire is modeled as a single sine-wave current generator
    • C. A wire is modeled as a single sine-wave voltage source
    • D. A wire is modeled as a series of segments, each having a distinct value of voltage across it
  • E9B11 (C) What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength? #card
    • A. Ground conductivity will not be accurately modeled
    • B. The resulting design will favor radiation of harmonic energy
    • C. The computed feed point impedance may be incorrect
    • D. The antenna will become mechanically unstable