Deck 15: Waveguides and Radar

Question 1

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

A) a twist
B) an H-bend
C) an E-bend
D) all of the above

Answer 1

D

Question 2

The process of having the frequency of a reflected signal shift due to relative motion between the source and reflecting object is known as:

A) the Doppler effect.
B) radar
C) cavity tuning.
D) directional coupling.

Answer 2

A

Question 3

Circular waveguide is advantageous to rectangular waveguide in:

A) its size.
B) its cost.
C) its cross-sectional area.
D) continuously rotating radar applications.

Answer 3

D

Question 4

The type of wave propagated by a waveguide is:

A) acoustic
B) quantum
C) mechanical
D) electromagnetic

Question 5

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

A) waveguides
B) antennas.
C) transmission lines

Question 6

A radar wave has a duty cycle of 0.7%. The pulse width is 4 s. Determine the pulse repetition time.

A) 286 us
B) 400 us
C) 3 ms
D) 150 us

Question 7

Define the term "backscatter."

A) refers to the reflection of the radio waves striking the source and reflecting back to the RFID tag
B) refers to the reflection of the radio waves striking the RFID tag and reflecting back to the transmitter source
C) refers to the reflection of the audio waves striking the RFID tag and reflecting back to the transmitter source
D) can be used to measure the weight of the object.

Question 8

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

A) a hybrid tee.
B) a flap attenuator.
C) a slider screw tuner.
D) a directional coupler.

Question 9

Explain how power is provided to a passive RFID tag.

A) power is provided by the reader.
B) power is provided by rectifying the AF energy transmitted by the reader that strikes the RF tag antenna.
C) power is provided by rectifying the RF energy transmitted by the reader that strikes the RF tag antenna.
D) none of the above

Question 10

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

A) the same length.
B) smaller
C) larger

Question 11

The amount of coupling (dB) is determined by:

A) guide wavelength, (lamda)*g.
B) type of transmission mode.
C) type of waveguide.
D) ratio of output power and incident power.

Question 12

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

A) environmental conditions
B) reliability
C) power level and efficiency
D) cost and maintenance

Question 13

The range (miles) to a target is 6 miles. What is the time interval between transmission and reception?

A) 120 us
B) 74 us
C) 40 ns
D) none of the above

Question 14

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

A) TM-11
B) TE-10
C) TE-20
D) TE-11
E) TM-21

Question 15

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

A) tees
B) E bend
C) H bend
D) twist

Question 16

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

A) TH
B) HM
C) TE
D) TM

Question 17

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

A) changing the direction of propagation of the signal in the waveguide.
B) minimizing VSWR in a waveguide system.
C) minimizing the resistive losses of the waveguide.

Question 18

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

A) tee
B) loop
C) probe
D) aperture

Question 19

What are the three parameters that define an RFID system? (select three)

A) frequency of operation
B) cost
C) communication protocol
D) means of powering the tag

Question 20

When the target is too close to the transmitter the following is usually detected:

A) maximum range echoes
B) ambiguous signal
C) double range echoes
D) peak power

Question 21

What are the three frequency bands typically used for RFID tags? (select three)

A) HF - 13.56 MHz
B) LF - 125/134 kHz
C) UHF - 860-960 MHZ and 2.4 GHz
D) HF - 17.25 MHz