Microwave Devices and Antennas

1. Which of the following factors is not used to determine a mode of energy transmission?

2. The type of wave propagated by a waveguide is:

3. The side arm of the shunt tee is used to shunt the E field in which mode?

4. Which of the following is used to change the plane of polarization of the wave?

5. The amount of coupling (dB) is determined by:

6. At a frequency of 1 GHz and a transmitter-receiver distance of 1500 ft., which is the most efficient device for energy transfer?

7. Which is the dominant and most widely used mode of waveguide operation?

8. One wavelength of waveguide, when compared to one wavelength of free space is:

9. Circular waveguide is advantageous to rectangular waveguide in:

10. In order to change the direction of propagation in waveguide, what is used?

11. The primary use of slide screw and double-slug tuners is in:

12. A waveguide that can distinguish between the waves traveling in opposite directions is called:

13. Which is not a method for coupling energy into or out of a waveguide?

14. As electromagnetic waves propagate in a waveguide:

15. Waveguides are used commonly for microwave signals because:

16. The wavelength of a wave in a waveguide

17. Main difference between the operation of transmission lines and waveguides is that:

18. Which is a false statement? Compared with equivalent transmission lines, 3 GHz waveguides:

19. There appears an extra electric component in the direction of propagation in a particular mode in a waveguide. This describes:

20. An electromagnetic wave that reflects at an angle from a wall would have their wavelength along the wall:

21. An electromagnetic wave acquires an apparent velocity greater than the velocity of light in space due to reflection from a plane conducting wall in a waveguide. This is?

22. If the free space wavelength of a signal equals the cut-off wavelength of the guide,________.( Indicate the false statement)

23. A waveguide has a full wave of electric intensity change between the two further walls and no component of the electric field in the direction of propagation.

24. Indicate the false statement. The dominant mode is preferred as the propagation mode with a rectangular waveguides because:

25. The disadvantage of microstrip over a stripline circuits is that the microstrip

26. A choke flange may be used to couple two waveguides:

27. Which one is not used to couple two generators to a waveguide system without coupling them to each other?

28. A waveguide tuning components that is not easily adjustable is:

29. A piston attenuator is a

30. Klystrons do not use cylindrical cavity resonators because they have______.

31. The advantage of using a directional coupler with three or more holes over a two-hole coupler is:

32. A ferrite is

33. Manganese ferrite may be used as _______ (false statement)?

34. A ferrite component’s maximum power handling capability is limited by the:

35. A PIN diode is

36. A duplexer is used

37. Circular waveguides may be preferred to rectangular ones because of

38. A word that can be followed by the word “waveguide”(false statement):

39. A waveguide used to reduce the cross-sectional dimensions

40. The best transmission medium is for handling high powers is:

41. A system that uses two ground planes.

42. An advantage of stripline using microstrip is its______(false statement).

43. An advantage of stripline over waveguides is its________(false statement)

44. A disadvantage of optical fibers over waveguides is:

45. For frequencies below 2 MHz, which antenna is used?

46. A λ/4 dipole at 500 MHz is used to receive a broadcast. Determine the length of the dipole.

47. Which of the following is used to determine antenna bandwidth?

48. Which of the following antennas matches well with the 300 Ω input impedance terminals?

49. Which of the following is a directional antenna?

50. An antenna created by taking a quarter-wavelength section of open wire line and bending each conductor outward 90 degrees is called:

51. It is desired to build a dipole to receive a 49 MHz broadcast. The optimum length for the dipole antenna is:

52. Any non-driven element of an antenna array such as a Yagi is called a:

53. Feeding the half-wave dipole (Hertz) antenna at the center results in an input impedance that is purely resistive and equal to

54. The half-wave dipole antenna has gain relative to an isotropic radiator of

55. Antenna gain provided with respect to an isotropic radiator is expressed as:

56. The antenna gain, given in decibel with respect to a dipole is expressed as:

57. An impedance matching device that spreads the transmission line as it approaches the antenna is called a:

58. A series inductance used to tune out the capacitive appearance of an antenna is called

59. A group of antennas or antenna elements arranged to provide the desired directional characteristics is called:

60. A small-loop antenna has a turn of wire whose dimensions are normally much smaller than:

61. A direction in space with minimal signal level is called a:

62. The characteristic impedance of twin lead is:

63. An antenna near the ground and ungrounded:

64. Which of the following is a non-resonant antenna?

65. A multiband HF receiving antenna.

66. An antenna best excited from a waveguide is a/an:

67. Which of the following reasons for using a counterpoise with antenna is not true

68. Which is not a reason for the use of an antenna coupler:

69. Which is not a wideband antenna?

70. Which of the following reasons is false for the use of a ground screen with an antenna

71. Yagi-Uda array has_______(false statement)?

72. Which antenna is circularly polarized?

73. Considered as a standard reference antenna for directive gain

74. The purpose of using top loading is to increase the antenna’s_______.

75. A statement describing a parabolic reflector with cassegrain feeding

76. Zoning is used with a dielectric antenna in order to

77. Because of its_______ helical antennas are used for satellite tracking

78. Discone antennas are

79. Which of the is not an omnidirectional antenna?

80. A rectangular waveguide has a width of 0.65 in and a height of 0.38 in. What is the cutoff frequency?

81. An air-dielectric waveguide has an inside cross section of 2 cm by 4 cm. Find the cutoff frequency for the TE10

82. Over what maximum frequency range is the waveguide usable for dominant mode?

83. Find the group velocity for the waveguide at a frequency of 5 GHz.

84. Find the phase velocity for the waveguide at a frequency of 5 GHz.

85. Find the guide wavelength.

86. A waveguide has a cutoff frequency for the dominant mode of 10 GHz. Two signals with frequencies of 12 and 17 GHz propagate down a 50 m length of the guide. Calculate the group velocity for 12GHz

87. Calculate the group velocity for 17GHz.

88. Calculate the arrival time for the 12GHz.

89. Calculate the difference of the arrival time between the two signals.

90. A dipole antenna has a radiation resistance of 67 Ω and a loss resistance of 5 Ω, measured at the feed point. Calculate the efficiency.

91. Two antennas have gains of 5.3 dBi and 4.5 dBd, respectively. Which has greater gain?

92. A dipole antenna has an efficiency of 85%. Calculate its gain in decibels.

93. An antenna with a gain of 13.95 dBi has a gain of _____ in dBd.

94. A transmitter power of 30W is fed to an antenna with a gain of 12.4 dBi. Find the EIRP in dBm.

95. A ground plane antenna connected to a 50Ω cable has an SWR of:

96. Calculate the length of the bow tie antenna at 310 MHz.

97. Calculate the radiation resistance of the bow tie antenna at 310 MHz and φ = 35°.

98. Find the beam width of an antenna with a gain of 15 dB.

99. An antenna has a gain of 14 dB. It is fed by an RG- 8/U transmission line 250 ft long whose attenuation is 3.6 dB/100 ft at 220 MHz. The transmitter output is 50 W. Calculate the transmission line loss

100. Calculate the ERP.