Microwave Communication Multiple Choice Questions(MCQs)& Answers
CONCEPTS & THEORIES
microwave-communication
About Microwave Communication
Within the broader spectrum of radio frequency (RF) communications, point-to-point communications are usually carried out using microwave frequencies between 1 GHz and 100 GHz along line-of-sight (LOS) paths called links.
It is a line-of-sight wireless communication technology that uses high frequency beams of radio waves to provide high speed wireless connections that can send and receive voice, video, and data information.
Microwave radio transmission is commonly used in point-to-point communication systems on the surface of the Earth, in satellite communications, and in deep space radio communications. Other parts of the microwave radio band are used for radars, radio navigation systems, sensor systems, and radio astronomy.
Microwave Frequency Bands
Microwave signals are often divided into three categories:
1. ultra high frequency (UHF) (0.3-3 GHz);
2. super high frequency (SHF) (3-30 GHz); and
3. extremely high frequency (EHF) (30-300 GHz).
In addition, microwave frequency bands are designated by specific letters. The designations by the Radio Society of Great Britain are given below.
Microwave frequency bands vs Designation Frequency range
L band-1 to 2 GHz
S band-2 to 4 GHz
C band-4 to 8 GHz
X band-8 to 12 GHz
Ku band-12 to 18 GHz
K band-18 to 26.5 GHz
Ka band-26.5 to 40 GHz
Q band-30 to 50 GHz
U band-40 to 60 GHz
V band-50 to 75 GHz
E band-60 to 90 GHz
W band-75 to 110 GHz
F band-90 to 140 GHz
D band-110 to 170 GHz
QUESTIONS
Microwave Communication Multiple Choice Questions(MCQs)& Answers
1
Which of the following permits a microwave signal to travel in one direction with virtually no loss, but severely attenuates any signal attempting to travel in the reverse direction?
Answer: Isolator
2
A thin layer of dirt and grime coverts the reflecting surface of the parabolic dish of a radar set. The particular effect on the performance of the radar will be
Answer: No noticeable effect
4
If the duration of the radar transmitted pulse, on a particular range of operation, is increased, the required bandwidth of the receiver’s IF amplifiers
Answer: May be decreased
6
At what position is the input signal inserted into a traveling-wave tube?
Answer: At the cathode end of the helix
8
A shipboard equipment which measures the distance between the ship’s bottom and the ocean floor.
Answer: SONAR
9
In microwave transmission using digital radio, what causes most intersymbol interference?
Answer: Delayed spreading
12
What do you call an attenuation that occurs over many different wavelengths of the carrier?
Answer: Slow fading
16
The maximum usable range of the usual radar set (on any particular range setting) is determined by
Answer: The interval between transmitted pulses
17
A reflex klystron is oscillating at the frequency of its resonant cavity. If the reflector voltage is made slightly less negative, the
Answer: The frequency will decrease
18
The coarse frequency adjustment of a reflex klystron is accomplished by
Answer: Adjusting the flexible wall of the resonant cavity
19
In a pulsed radar set, the STC circuit is used to
Answer: Reduce interference from the effects of sea return
20
In a pulsed radar set, the function of the duplexer is to
Answer: Allow the transmitter and the receiver to operate from a common antenna
21
The highest frequency which a conventional vacuum-tube oscillator can generate is not limited by the
Answer: Degree of emission from the cathode
23
Which of the following operating frequencies is used for the modern loran navigational system?
Answer: Loran C: 100 kHz
26
What is the purpose of the electromagnetic field which surrounds a traveling-wave tube?
Answer: To keep the electrons from spreading out
27
A traveling-wave tube (TWT) amplifies by virtue of
Answer: The absorption of energy by the signal from an electron stream
28
When it is desired that short-range targets be clearly seen on a pulsed-radar set, it is important that the receiver and display system have
Answer: The shortest possible time
29
The aquadag coating on the inside of PPI tube is used
Answer: As a second anode and to prevent the build-up of secondary field
30
A magnetron is operated at a duty cycle of 0.001. It has a peak power output of 100 kilowatts. Its average power is
Answer: 100 watts
32
Theoretically electromagnetic radiation field strength varies in inverse proportion to the square of the distance, but when atmospheric attenuation effects and the absorption of the terrain are taken into account the attenuation can be as high as the inverse _______ power of the distance.
Answer: Sixth
34
the antenna separations (in meters) required for optimum operation of a space diversity system can be calculated from:
where R = effective earth radius (m) and L = path length (m)
Answer: S = 3λR/L