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  • Question

  • If D is diameter of circular waveguide the cutoff wave-length for TE11 mode is equal to


  • Options
  • A. 1.706 D
  • B. 2.11 D
  • C. 0.82 D
  • D. 0.41 D

  • Correct Answer
  • 1.706 D 

    Explanation
    Some applications require dual polarization capability. Circular waveguide has this capability.

    These analysis uses cylindrical coordinates.

    In circular waveguide TE11 mode has the lowest cut off frequency and is the dominant mode.

    If D is diameter of waveguide

    ?c = 1.706 D for TE11 mode

    ?c = 1.029 D for TE21 mode

    ?c = 0.82 D for TE01 mode

    ?c = 1.306 D for TM01 mode.

    Microwave Communication problems

    Search Results

    • 1. The transit time (in cycles) for electrons in repeller space of reflex klystron oscillator for sustaining oscillations is (n is any integer)

    • Options
    • A. 2(n - 1)
    • B. 2n - 1
    • C.
    • D.
      • Discuss
    • 2. Which one of the following can be used for amplification of microwave energy?

    • Options
    • A. TWT
    • B. Magnetron
    • C. Reflex klystron
    • D. Gunn diode
      • Discuss
    • 3. If 'a' is the width of rectangular wave guide and '?' is the wave length, then

    • Options
    • A.
    • B.
    • C.
    • D.
      • Discuss
    • 4. Which of the following modes of transmission will not be supported by a rectangular waveguide?

    • Options
    • A. TE15
    • B. TE12
    • C. TM11
    • D. TM10
      • Discuss
    • 5. In a TWT the amplitude of resultant wave travelling down the helix remains constant

    • Options
    • A. True
    • B. False
      • Discuss
    • 6. In the given figure forward current wave has a magnitude of

    • Options
    • A. 0.45 A
    • B. 0.3 A
    • C. 0.2 A
    • D. 0.1 A
      • Discuss
    • 7. The two terms used to describe performance of a directional coupler are

    • Options
    • A. coupling and directivity
    • B. gain and coupling
    • C. gain and directivity
    • D. gain and isolation
      • Discuss
    • 8. Consider the following statements

      1. Gunn diode can be used in combinational logic circuits.
      2. Gunn diode can be used in sequential logic circuits.
      3. Both Gunn diode and GaAs Mesfet can be used in logic circuits.
      Which of the above statements are correct?

    • Options
    • A. 1, 2, and 3
    • B. 1 and 2 only
    • C. 2 and 3 only
    • D. 1 and 3 only
      • Discuss
    • 9. The external magnetic field in a magnetron is such that lines are

    • Options
    • A. parallel to the axis of cathode
    • B. perpendicular to the axis of cathode
    • C. inclined to the axis of cathode
    • D. either (b) or (c)
      • Discuss
    • 10. To ensure that only dominant mode TE10 is allowed to propagate in an air filled rectangular waveguide, the lower frequency limit and upper frequency limit are

    • Options
    • A. about 25% above fc for TE10 and 5% below fc for TE20 mode respectively
    • B. about 50% above fc for TE10 and 25% below fc for TE20 mode respectively
    • C. about 25% above fc for TE10 and 25% below fc for TE20 mode respectively
    • D. none of the above
      • Discuss

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