This is the Multiple Choice Questions in Chapter 17: Microwave Devices from the book Electronic Communication Systems by Roy Blake
See also: MCQ in Electronic Communication Systems by George Kennedy
Start Practice Exam Test Questions
Choose the letter of the best answer in each questions.
MULTIPLE CHOICE
1. The microwave frequency range is considered to start at:
a. 100 MHz
b. 1 GHz
c. 10 GHz
d. 100 GHz
Answer: Option B
Solution:
2. The UHF range is:
a. below the microwave range
b. inside the microwave range
c. above the microwave range
d. same as the microwave range
Answer: Option A
Solution:
3. The dominant mode of a waveguide depends on:
a. the shape of the waveguide
b. the power level of the signal
c. the point of signal injection
d. none of the above
Answer: Option A
Solution:
4. The dominant mode of a rectangular waveguide is:
a. TE 01
b. TM 01
c. TE 10
d. TM 10
Answer: Option C
Solution:
5. The dominant mode of a circular waveguide is:
a. TE01
b. TM01
c. TE11
d. TM11
Answer: Option C
Solution:
6. Circular waveguides use TM01 mode because:
a. it is dominant
b. of its circular symmetry
c. it is the only mode possible
d. it is more efficient
Answer: Option B
Solution:
7. The characteristic impedance of a waveguide:
a. is fixed
b. depends on the frequency it carries
c. depends on the longer dimension of its cross section
d. both b and c
Answer: Option D
Solution:
8. Power can be coupled into or out of a waveguide:
a. with a magnetic field probe
b. with an electric field probe
c. through a hole in the waveguide
d. all of the above
Answer: Option D
Solution:
9. Directional couplers for waveguides are characterized by:
a. their insertion loss
b. their coupling specification
c. their directivity
d. all of the above
Answer: Option D
Solution:
10. Striplines and microstrips are used to:
a. couple sections of waveguide
b. couple waveguides to antennas
c. couple components on a circuit board
d. none of the above
Answer: Option C
Solution:
11. A resonant cavity is a type of:
a. tuned circuit
b. defect in a waveguide
c. antenna
d. none of the above
Answer: Option A
Solution:
12. A TEE connector used with waveguides is:
a. an H-plane TEE
b. an E-plane TEE
c. a “magic” TEE
d. all of the above
Answer: Option D
Solution:
13. TWT stands for:
a. Transverse Wave Transmission
b. Transverse-Wave Tube
c. Traveling-Wave Tube
d. Traveling-Wave Transmission
Answer: Option C
Solution:
14. An “isolator” is a device that:
a. isolates frequencies in a waveguide
b. allows a signal to pass in one direction only
c. separates signals among various ports
d. prevents microwaves from leaking out of a waveguide
Answer: Option B
Solution:
15. A “circulator” is a device that:
a. rotates signal polarity in a waveguide
b. allows a signal to pass in one direction only
c. separates signals among various ports
d. prevents microwaves from being “trapped” in a waveguide
Answer: Option C
Solution:
16. GaAs stands for:
a. gallium arsenide
b. gallium assembly
c. gallium astenite
d. none of the above
Answer: Option A
Solution:
17. IMPATT stands for:
a. impact avalanche and transit time
b. induced mobility at transmission time
c. implied power at transmission terminal
d. none of the above
Answer: Option A
Solution:
18. YIG stands for:
a. Yttrium-Iron-Gallium
b. Yttrium-Iron-Germanium
c. Yttrium-Iron-Garnet
d. none of the above
Answer: Option C
Solution:
19. A YIG can be tuned by applying:
a. an electric field
b. a magnetic field
c. mechanical pressure
d. an “exciter” signal
Answer: Option B
Solution:
20. The device commonly used in microwave ovens is the:
a. TWT
b. klystron
c. magnetron
d. YIG
Answer: Option C
Solution:
21. The device commonly used in satellite communications is the:
a. TWT
b. klystron
c. magnetron
d. YIG
Answer: Option A
Solution:
22. The device commonly used in UHF transmitters is the:
a. TWT
b. klystron
c. magnetron
d. YIG
Answer: Option B
Solution:
23. A microwave phased array is often made using:
a. slots
b. Yagis
c. Fresnel lenses
d. all of the above
Answer: Option A
Solution:
24. RADAR stands for:
a. radio ranging
b. radio depth and ranging
c. radio detection and ranging
d. remote detection and ranging
Answer: Option C
Solution:
25. RADAR uses:
a. pulsed transmission
b. continuous transmission
c. the Doppler effect
d. all of the above
Answer: Option D
Solution:
26. The maximum effective range for pulsed radar:
a. increases with increasing repetition rate
b. decreases with increasing repetition rate
c. decreases with increasing pulse period
d. none of the above
Answer: Option B
Solution:
27. The minimum effective range for pulsed radar:
a. increases with increasing pulse duration
b. decreases with increasing pulse duration
c. is always a tenth of the maximum range
d. none of the above
Answer: Option A
Solution:
COMPLETION
1. ____________________ is the effect of a pulse “spreading out” as it travels through a waveguide.
Answer: Dispersion
Solution:
2. The electric field is ____________________ along the walls of a rectangular waveguide.
Answer: zero
Solution:
3. The waveguide mode with the lowest cutoff frequency is the ____________________ mode.
Answer: dominant
Solution:
4. In TE10 mode, the ____________________ field peaks in the middle of the waveguide cross section.
Answer: electric
Solution:
5. In TE20 mode, the electric field has ____________________ peaks in the waveguide cross section.
Answer: two
Solution:
6. In a circular waveguide, ____________________ mode is used because of its circular symmetry.
Answer: TM01
Solution:
7. A waveguide acts as a ____________________-pass filter.
Answer: high
Solution:
8. In a waveguide, group velocity is always ____________________ than the speed of light.
Answer: slower
Solution:
9. In a waveguide, phase velocity is always ____________________ than the speed of light.
Answer: faster
Solution:
10. In a waveguide, impedance ____________________ as frequency increases.
Answer: decreases
Solution:
11. A ____________________ TEE is a combination of E-plane and H-plane TEES.
Answer: hybrid
Solution:
12. The Q of a resonant cavity is very ____________________ compared to lumped LC circuits.
Answer: high
Solution:
13. A wavemeter is a resonant ____________________ with an adjustable plunger.
Answer: cavity
Solution:
14. A Gunn device oscillates because of its negative ____________________.
Answer: resistance
Solution:
15. Both magnetrons and TWTs are slow ____________________ tubes.
Answer: wave
Solution:
16. Both klystrons and TWTs are ____________________-beam tubes.
Answer: linear
Solution:
17. A ____________________ antenna is just a waveguide with a hole in it.
Answer: slot
Solution:
18. A ____________________ antenna is a flat piece of copper on an insulating substrate with a ground plane on the other side.
Answer: patch
Solution:
19. The radar cross section of a target is typically ____________________ than its actual size.
Answer: smaller
Solution:
20. The frequency of the returned signal will be ____________________ than the transmitted signal if the target is moving toward the radar antenna.
Answer: higher
Solution:
SHORT ANSWER
1. Calculate the TE10 cutoff frequency for a rectangular waveguide if the longer dimension of its cross section is 5 cm.
Answer: 3 GHz
Solution:
2. Calculate the group velocity in a waveguide carrying a signal that is twice its cutoff frequency.
Answer: 260 x 106 meters per second
Solution:
3. Calculate the phase velocity in a waveguide carrying a signal that is twice its cutoff frequency.
Answer: 346 x 106 meters per second
Solution:
4. Calculate the wavelength of a 2-GHz signal in a waveguide with a 1-GHz cutoff frequency.
Answer: 173 millimeters
Solution:
5. Find the gain in dBi of a 10-GHz horn antenna with dE = dH= 60 mm.
Answer: 14.8
Solution:
6. Find the maximum unambiguous range for a pulsed radar sending 10k pulses per second.
Answer: 15 km
Solution:
7. Find the minimum unambiguous range for a pulsed radar sending 2-ยตsec duration pulses.
Answer: 300 meters
Solution:
Complete List of MCQ in Electronic Communication Systems by Blake
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