RF Cafe Quiz #43

Plasma Antennas

RF Engineering Quizzes - RF CafeAll RF Cafe Quizzes make great fodder for employment interviews for technicians or engineers - particularly those who are fresh out of school or are relatively new to the work world. Come to think of it, they would make equally excellent study material for the same persons who are going to be interviewed for a job. Bonne chance, Viel Glück, がんばろう, buena suerte, удачи, in bocca al lupo, 행운을 빕니다, ádh mór, בהצלחה, lykke til, 祝你好運. Well, you know what I mean: Good luck!

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Note: Some material based on books have quoted passages.

Plasma Antennas - RF Cafe Featured BookThis quiz is based on the information presented in Plasma Antennas, by Theodore Anderson.

Note: Some of these books are available as prizes in the monthly RF Cafe Giveaway.

1.  When the frequency of operation of a plasma antenna decreases, what is the corresponding requirement for plasma density?

a)  Plasma density must increase

b)  Plasma density remains the same

c)  Plasma density must decrease

d)  Plasma density not a factor

2.  How does plasma density affect signal phase during reflection and/or refraction?

a)  Plasma density affected only during reflection

b)  Plasma density affected only during refraction

c)  Plasma density affected by both reflection and refraction

d)  Plasma density does not affect phase

3.  How is characteristic impedance controlled in a plasma antenna?

a)  By varying the plasma density

b)  By varying the plasma material

c)  By varying the plasma geometry

d)  All the above

4.  What commonly available component is useful as a plasma antenna demonstrator?

a)  Fluorescent bulb

b)  Neon bulb

c)  Microwave oven

d)  Lava lamp

5.  What is plasma, by the way?

a)  A biological gel

b)  An ionized gas

c)  An ionized liquid

d)  Energetic electrons

6.  In a multiple frequency nested plasma antenna, where is the highest frequency antenna element located relative to the lowest frequency antenna element?

a)  Lowest frequency element on the inside, highest frequency element on the outside

b)  Lowest frequency element on the outside, highest frequency element on the inside

c)  Element location independent of frequency

d)  Plasma antennas are only single frequency structures

7.  What is plasma "windowing?"

a)  Creating electronically switched portal regions around an antenna array

b)  Opening or closing the plasma antenna feedline

c)  Varying the Anderson ratio and/or Pella factor of the plasma material

d)  Using the Windows operating system to control a plasma antenna

8.  What is a "smart" plasma antenna?

a)  A plasma antenna that uses higher order control algorithms

b)  Lab slang for a plasma antenna that uses a dummy load

c)  2nd generation plasma antennas

d)  A plasma antenna that use adaptive techniques to control beam patterns

9.  How can plasma materials be used to provide filtering?

a)  Plasmas are frequency independent, and therefore not useful as filters

b)  Layering regions of plasmas allows specific frequencies to be selected and others rejected

c)  Plasmas cannot be controlled well enough for use as filtering elements

d)  Structures are too large for use as practical filtering elements

10.  Who is undoubtedly the master of using commercial fluorescent tubes for constructing plasma devices like antennas, filters, and switches?

a)  Theodore Anderson

b) General Electric

c)  Richard Sylvania

d)  Douglas Philips

Need some help? Click here for the answers and explanations.