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ECE :: Microwave Communication

  1. Out of modes TE20 and TE30 of propagation of electromagnetic engery

  2. A.
    both have the same cutoff frequency
    B.
    TE20 has lower cut off frequency as compared to TE30
    C.
    TE30 has lower cutoff frequency as compared to TE20
    D.
    either (a) or (c)

  3. A TE10 rectangular waveguide is to be designed for operation over 25-35 GHz and the band centre is 1.5 times the cutoff frequency. The dimension of broadside is

  4. A.
    15 mm
    B.
    10 mm
    C.
    9 mm
    D.
    7.5 mm

  5. In a klystron amplifier the force on all electrons

  6. A.
    causes acceleration of all electrons
    B.
    causes retardation of all electrons
    C.
    causes acceleration of some electrons and retardation of others
    D.
    none of the above

  7. If load impedance ZL >> Z0, then

  8. A.
    Z0 = ZL (VSWR)
    B.
    ZL = Z0 (VSWR)
    C.
    ZL = Z0 (VSWR - 1)
    D.
    ZL = Z0 VSWR

  9. The inductance of a twin feeder used to connect antenna to TV receiver is about

  10. A.
    0.2 μ H/m
    B.
    0.6 μ H/m
    C.
    1.6 μ H/m
    D.
    10 μ H/m

  11. When resonant cavities are coupled together the result is

  12. A.
    one resonant frequency
    B.
    n resonant frequencies
    C.
    resonant frequencies
    D.
    either (b) or (c)

  13. For a rectangular waveguide having width a and height b, the cutoff wavelength for TM11 mode is equal to


  14. The path length between ports 1 and 2 for the two waves in a hybrid ring is

  15. A.
    1
    B.
    C.
    D.

  16. The radiation resistance of a circular loop of one turn is 0.01 ohm. For 5 turn loop the radiation resistance is

  17. A.
    0.002 Ω
    B.
    0.01 Ω
    C.
    0.05 Ω
    D.
    0.25 Ω

  18. As wavelength decrease the size of high directivity antenna

  19. A.
    decreases
    B.
    increases
    C.
    is not affected
    D.
    either (b) or (c)