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ECE :: Electromagnetic Field Thoery

  1. For a reflection co-efficient of 0.5, the value of SWR is

  2. A.
    -1
    B.
    1
    C.
    2
    D.
    3

  3. A rectangular waveguide having TE10 mode as dominant mode is having a cut off frequency of 18 GHz for the TE30 mode. The inner broad wall dimension of the rectangular waveguide is

  4. A.
    5/3 cm
    B.
    5 cm
    C.
    5/2 cm
    D.
    10 cm

  5. A 50 p characteristic impedance line is connected to a load which shows a reflection coefficients of 0.268. If Vin = 15 volt, then the net power delivered to the load will be

  6. A.
    0.139 W
    B.
    1.39 W
    C.
    0.278 W
    D.
    2.78 W

  7. Cassergain feed is used with a parabolic reflector to

  8. A.
    increase the gain of the system
    B.
    increase the beamwidth of the system
    C.
    reduce the size of the main reflector
    D.
    allow the feed to be placed at a convenient point

  9. Voltage standing wave pattern in a loss less transmission line with characteristic impedance 50 Ω and a resistive load is shown in the figure.

    The value of load resistance is

  10. A.
    50 Ω
    B.
    200 Ω
    C.
    12.5 Ω
    D.
    0 Ω

  11. For the same length of arrays, half power beam-width of binomial array

  12. A.
    is equal to that of uniform arrays
    B.
    is less than that of uniform array
    C.
    is more than that of uniform array
    D.
    is negligible as compared to that of uniform array

  13. The effective electrical length of an antenna is __________ its physical length

  14. A.
    greater than
    B.
    equal to
    C.
    less than
    D.
    none of the above

  15. The direction in a Yagi Uda antenna is longer than the radiating element.

  16. A.
    True
    B.
    False