RF4 A1

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RF4 A1
2013-05-20 00:16:38
radio frequency engineering electronics

edinburgh uni rf4 exam prep
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  1. Define in words what is meant by the term “gain” in the context of an antenna.
    • Power radiated by an antenna may be concentrated in a particular direction - this proprety iss expressed in terms of a power gain G
  2. Define in words what is meant by the term “directivity” in the context of an antenna.
  3. Make a sketch showing the radiation pattern of a half-wave dipole. Indicate the directions of maximum and minimum radiation and state its maximum gain value.
  4. Sketch a graph showing how the resistive and reactive parts of the impedance of a dipole vary as its length varies from zero to one wavelength.
  5. What does the term “polarisation” describe in a radio or microwave radiation field?
  6. What are the three types of polarisation?
  7. A radar system is to have a maximum range of 100 km. What is the maximum pulse repetition frequency it can use?
  8. A Doppler radar operates at a frequency of 10 GHz. Calculate the Doppler frequency produced by a target moving at 1 m/s.
    • f=c/lambda
  9. At what distance do the “near” and “far” fields around a conductor carrying an alternating current have the same value? Justify your answer.
  10. Write down the physical meaning of the four S-parameters describing a two-port network.
  11. What three parameters determine the characteristic impedance of a microstrip transmission line?