Microwave Devices and Circuits MCQs

Question 1

The transit time in the repeller space of a reflex klystron must be n + ?4 cycle to ensure that

Accepted Answer

returning electrons given energy to the gap oscillations

Answer

electrons are accelerated by the gap voltage on their return

Answer

it is equal to the period of the cavity oscillations

Answer

the repeller is not damaged by striking electrons

Question 2

Microwave ovens operate at a frequency of

Accepted Answer

2.45 GHz

Answer

1.37 GHz

Answer

3.37 GHz

Answer

22 LIHz

Question 3

The modes in a reflex klystron

Accepted Answer

all give much the same frequency but different transit times

Answer

result from excessive transit time across the resonator cap

Answer

correspond to different oscillating frequencies of the cavity

Answer

are caused by spurious frequency modulation

Question 4

If a narrow slot is cut in the wall of a waveguide so that it disturbs current flow, that slot is said to be

Accepted Answer

A radiating slot

Answer

A non-radiating slot

Answer

None of the above

Answer

Both (a) and (b)

Question 5

TWT is preferred to multicavity klystron amplifier because it is

Accepted Answer

greater B.W.

Answer

more efficient

Answer

has higher number of modes

Answer

produces a higher output power

Question 6

Indicate the false statement Klystron amplifiers may use intermediate cavities to

Accepted Answer

prevent the oscillations that occure in twocavity klystron

Answer

improve the power gain

Answer

increase the efficiency of the klystron

Answer

increase the bandwidth of the device

Question 7

The reflex klystron is often preferred to the two-cavity klystron oscillator because the former

Accepted Answer

is easier to tune

Answer

is more efficient

Answer

has higher number of modes

Answer

produces a higher output power

Question 8

A quarter-wave stub shorted at the end has high impedance

Accepted Answer

?4 back from the short X

Answer

at shorted end

Answer

? back from the short 2

Answer

at the centre

Question 9

A transmission line has a VSVVR of 2, the reflection coefficient is 1

Accepted Answer

?3

Answer

0

Answer

1?

Answer

2