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ECE :: Microwave Communication

  1. If f is the frequency of electromagnetic wave, fc is cutoff frequency, then in a rectangular waveguide

  2. A.
    attenuation is low when f > fc
    B.
    attenuation is low when f < fc
    C.
    attenuation is high when f < fc
    D.
    either (b) or (c)

  3. Assertion (A): The condition of minimum distortion in a transmission line is L = RC/G.

    Reason (R): Line loading means addition of inductance to satisfy the condition L = RC/G.

  4. A.
    Both A and R are correct and R is correct explanation of A
    B.
    Both A and R are correct but R is not correct explanation of A
    C.
    A is correct but R is wrong
    D.
    A is wrong but R is correct

  5. A magnetron has a cylindrical cathode surrounded by an anode structure having cavities opening into interaction space by means of slots

  6. A.
    True
    B.
    False

  7. The correct sequence of parts in klystron amplifier are

  8. A.
    anode, catcher cavity, cathode, buncher cavity
    B.
    cathode, buncher cavity, catcher cavity, cavity
    C.
    anode, buncher cavity, catcher cavity, cathode
    D.
    cathode, catcher cavity, anode, buncher cavity

  9. A transmission line has Z0 = 300 Ω and ZL = (300 - j300) ohm. The transmission coefficient is

  10. A.
    1.265 ∠ - 18.43°
    B.
    1.01 ∠ - 10°
    C.
    1.14 ∠ 66.68°
    D.
    1.09 ∠ 66.68°

  11. In a reflex klystron oscillator, repeller electrode is at

  12. A.
    low positive potential
    B.
    high positive potential
    C.
    negative potential
    D.
    zero potential

  13. A quarter wave line short circuited at load end behaves as

  14. A.
    an inductance
    B.
    an inductance and capacitance in series
    C.
    a capacitance
    D.
    an inductance and capacitance in parallel

  15. A (75 - J50) ohm load is connected to a coaxial of Z0 = 75 ohm at 10 GHz. The best method of matching is to connect

  16. A.
    an inductance at load
    B.
    a short circuited stub at load
    C.
    a short circuited stub at specific distance from load
    D.
    a capacitance at specific distance from load

  17. The width of a radio beam from a 1 m diameter parabolic antenna at 1 GHz is about

  18. A.
    100°
    B.
    50°
    C.
    D.

  19. Which one of the following is transferred locking electron device C antenna?

  20. A.
    BARITT diode
    B.
    IMPATT diode
    C.
    Gunn diode
    D.
    Step recovery diode