1. The phase velocity for the TE10 mode in an air filled rectangular waveguide is
Correct : C. equal to c
2. The phase velocity of an electrometric wave propagating in a hollow metallic
rectangular waveguide in the TE10 mode is
Correct : C. equal to velocity of light in free space
3. . Consider an air filled rectangular waveguide with a cross – section of5 cm × 3 cm.
For this waveguide, the cut off frequency (in MHz) of TE21mode is
Correct : A. 7.81 ghz
4. The cut off frequency of waveguide depends upon
Correct : A. the dimensions of the waveguide.
5. ency for
the dominant mode is
Correct : A. 2.5 ghz
6. ency of 30
GHz is (free space impedance 0 =377 Ω)
Correct : B. 400 Ω
7. When an electromagnetic waves are propagated in a waveguide
Correct : B. they are reflected from the walls but do not travel along them
8. Which of the following waveguides tuning components is not easily adjustable?
Correct : C. iris
9. A directional coupler with three or more holes is sometimes used in preference to
the two-hole couple
Correct : C. to reduce spurious mode generation
10. A ferrite is
Correct : A. a nonconductive with magnetic properties
11. A PIN diode is
Correct : C. suitable for use as a microwave switch
12. A microwave tube amplifier uses an axial magnetic field and a radial electric field.
This is the
Correct : B. coaxial magnetron
13. Indicate the false statement. Transit time in microwave tubes will be reduced if
Correct : C. multiple or coaxial leads are used
14. The multicavity klystron
Correct : A. is not a good low-level amplifier because of noise
15. The cavity magnetron uses strapping to
Correct : A. prevent mode jumping
16. The primary purpose of the helix in a traveling-wave tube is to
Correct : B. reduce the axial velocity of the rf field
17. The TWT is sometimes preferred to the magnetron as a radar transmitter output
tube because it is
Correct : A. capable of a longer duty cycle
18. A magnetron whose oscillating frequency is electronically adjustable over a wide
range is called a
Correct : D. vtm
19. A disadvantage of microstrip compared with strip line is that micro strip
Correct : A. does not readily lend itself to printed circuit techniques
20. For best low-level noise performance in the X-band, an amplifier should use
Correct : C. a step-recovery diode
21. Considering a coaxial transmission line, maximum voltage on the line divided by
the minimum voltage equals the
Correct : C. vswr
22. In a transmission line, if the SWR or maximum current to a minimum current
ratio of 2:1, the ratio of the maximum voltage to the minimum voltage is
Correct : D. 2:1
23. The load is properly matched with the transmission line if the standing wave ratio
is equal to
Correct : D. 1
24. Which of the following is used to measure SWR?
Correct : C. reflectometer
25. Reflections on a transmission line can occur when
Correct : B. impedance of the source and the load are mismatched
26. A measure of the mismatched between line and load impedance is called as
Correct : B. standing wave ratio
27. Power density is basically termed as power per unit are
Correct : B. radiated
28. Parabolic and lens antennas are extensively used for
Correct : B. micro waves
29. The television receiver antennas are usually
Correct : C. dipoles
30. Lens antennas used for microwaves are usually made of
Correct : B. polystyrene
31. One of the following antenna types is best excited from a waveguide
Correct : A. horn antenna
32. The parabolic and lens antennas are used extensively at
Correct : C. microwaves
33. Micro strip can be fabricated using:
Correct : A. photolithographic process
34. slotted antenna is used for
Correct : D. both uhf and vhf
35. The radar in which both transmission and reception is done using the same
antenna are called:
Correct : A. monostatic
36. __________ system obtains information about a target by transmitting a signal
and receiving the echo from the target.
Correct : A. radar
37. The solid area through which all the power radiated by the antenna is:
Correct : A. beam area
38. Which one of the following device behaviour is governed by bulk effect?
Correct : B. gunn diode
39. In a MTI radar, the quartz delay line is used to
Correct : D. subtract a complete scan from previous scan
40. Voltage reflection coefficient can be defined as:
Correct : B. ratio of amplitude of reflected voltage to the incident voltage wave
41. Flow of power in transmission line takes place through:
Correct : A. electric field and magnetic field
42. If a transmission line of a characteristics impedance 50 Ω is terminated with a load
impedance of 100 Ω, then the reflection co efficient is:
Correct : A. 0.3334
43. If a transmission line of characteristic impedance 50 Ω is to be matched to a load of
100Ω, then the characteristic impedance of the ƛ/4 transmission line to be used is:
Correct : D. 70.71 Ω
44. If there is no standing wave on a transmission line, then the value of SWR is:
Correct : B. 1
45. If a transmission line of characteristic impedance 50 Ω is terminated with a load
impedance of 150 Ω , then VSWR is:
Correct : A. 0.75
46. Smith chart is based on the polar plot of:
Correct : D. voltage reflection co-efficient
47. To get an admittance chart from an impedance chart:
Correct : B. smith chart has to be rotated by 180⁰
48. Propagation constant γ is given by:
Correct : A. α+jβ
49. The key difference between circuit theory and transmission line theory is:
Correct : D. electrical size
50. Transmission line is a _________ parameter network.
Correct : B. distributed
51. _________ and __________ contribute to the impedance of a transmission line in the
lumped element representation.
Correct : A. resistor, inductor
52. Characteristic impedance of a transmission line is:
Correct : B. impedance which is a constant at any point on the transmission line
53. The major advantage of single stub tuning over other impedance matching
techniques is:
Correct : D. all of the mentioned
54. Shunt stubs are preferred for:
Correct : A. strip and microstrip lines
55. In shunt stub matching, the key parameter used for matching is:
Correct : A. admittance of the line at a point
56. For co-axial lines and waveguides, ________ is more preferred.
Correct : B. short circuited stub
57. Maxwell’s equation for electromagnetic waves in a waveguide is:
Correct : A. ∇×e = -jωµ(vector h)
58. The modes of wave propagation that a rectangular waveguide can support are:
Correct : D. te,tm modes
59. In TM mode, if the direction of wave propagation is in ‘z’ direction, then:
Correct : A. hz=0
60. TEₒₒ mode for a rectangular waveguide:
Correct : C. does not exist
61. S parameters are expressed as a ratio of:
Correct : C. indecent and the reflected voltage waves
62. Ferrite isolators are ____ port microwave devices.
Correct : A. two
63. Directional coupler for waveguide are characterized by
Correct : D. all of the above
64. A “circulator” is a device that:
Correct : C. separates signals among various ports
65. The device commonly used in microwave ovens is the:
Correct : C. magnetron
66. Power dividers and couplers are ______ microwave components used for power
division or power combining.
Correct : A. passive
67. T- junction is an example for:
Correct : B. 3 port network
68. If a device is passive and contains no anisotropic elements, then the device
is_______ network.
Correct : A. reciprocal
69. If a microwave network is lossless, then S matrix of the microwave network is:
Correct : D. unitary
70. The junction resistance and capacitance of the intrinsic region in a PIN diode are
connected______ in the equivalent circuit of PIN diode.
Correct : B. parallel
71. The width of depletion region of a varactor diode ________with increase in reverse
bias voltage.
Correct : A. increases
72. When a reverse bias voltage exceeding the breakdown voltage is applied to an
IMPATT diode, it results in:
Correct : B. avalanche multiplication
73. Micro strip can be fabricated using:
Correct : A. photo lithographic process
74. ________ is a single cavity klystron tube that operates as on oscillator by using a
reflector electrode after the cavity.
Correct : B. reflex klystron
75. Klystrons operates on the principal of
Correct : D. velocity modulation
76. Which of the following can be used for amplification of microwave energy?
Correct : C. traveling wave tube
77. When the electric field applied to GaAs specimen is less than the threshold electric
field, the current in the material:
Correct : A. increases linearly
78. The primary purpose of the helix in a traveling-wave tube is to
Correct : B. reduce the axial velocity of the rf field
79. A cavity resonator can be represented by
Correct : A. an lc circuit
80. Ionospheric preparation is not possible for microwaves because
Correct : C. microwave will penetrate through the ionospheric layers
81. Which of the following is not possible in a circular wave guide ?
Correct : A. te10
82. The maximum theoretical output circuit efficiency of a double resonator klystron
amplifier is
Correct : C. 58%
83. The substrate of an MMIC must be a _____________ to accommodate the
fabrication of all the type of devices.
Correct : A. semiconductor
84. For the capacitors used in MMICs, the insulating dielectric films used are: