Question 1

The resonant frequency of an IMPATT diode is given by:

Accepted Answer

A)  vd/2L
B)  vd/l
C)  vd/2?l
D)  vdd/4?l A

Question 2

In Gunn diode oscillator, the Gunn diode is inserted into a waveguide cavity formed by a short circuit termination at one end

Accepted Answer

A) True 
 B)False  True

Question 3

Magnetrons are microwave devices that offer very high efficiencies of about 80%.

Accepted Answer

A) True 
 B)False  True

Question 4

The klystron tube used in a klystron amplifier is a __________type beam amplifier.

Accepted Answer

A)  linear beam
B)  crossed field
C)  parallel field
D)  none of the mentioned

Question 5

The production of power at higher frequencies is much simpler than production of power at low frequencies.

Accepted Answer

A) True 
 B)False

Question 6

The frequency of oscillation in Gunn diode is given by:

Accepted Answer

A)  vdom/ leff
B)  leff/ vdom
C)  leff/ wvdom
D)  none of the mentioned

Question 7

Klystron amplifiers have high noise output as compared to crossed field amplifiers.

Accepted Answer

A) True 
 B)False

Question 8

The number of semiconductor layers in IMPATT diode is:

Accepted Answer

A)  two
B)  three
C)  four
D)  none of the mentioned

Question 9

If the critical field in a Gunn diode oscillator is 3.2 KV/cm and effective length is 20 microns, then the critical voltage is:

Accepted Answer

A)  3.2 v
B)  6.4 v
C)  2.4 v
D)  6.5 v

Question 10

In crossed field tubes, the electron beam traverses the length of the tube and is parallel to the electric field.

Accepted Answer

A) True 
 B)False

Question 11

An essential requirement for the BARITT diode is that the intermediate drift region be completely filled to cause the punch through to occur.

Accepted Answer

A) True 
 B)False

Question 12

__________    is a single cavity klystron tube that operates as on oscillator by using a reflector electrode after the cavity.

Accepted Answer

A)  backward wave oscillator
B)  reflex klystron
C)  travelling wave tube
D)  magnetrons

Question 13

Microwave tubes are power sources themselves at higher frequencies and can be used independently without any other devices.

Accepted Answer

A) True 
 B)False

Question 14

The material used to fabricate IMPATT diodes is GaAs since they have the highest efficiency in all aspects.

Accepted Answer

A) True 
 B)False

Question 15

IMPATT diodes employ impact ionization technique which is a noisy mechanism of generating charge carriers.

Accepted Answer

A) True 
 B)False

Question 16

In a Gunn diode oscillator, the electron drift velocity was found to be 107 cm/second and the effective length is 20 microns, then the intrinsic frequency is:

Accepted Answer

A)  5 ghz
B)  6 ghz
C)  4 ghz
D)  2 ghz

Question 17

__________      is a microwave device in which the frequency of operation is determined by the biasing field strength.

Accepted Answer

A)  vtm
B)  gyratron
C)  helix bwo
D)  none of the mentioned

Question 18

If the length of the intrinsic region in IMPATT diode is 2 µm and the carrier drift velocity are 107 cm/s, then the nominal frequency of the diode is:

Accepted Answer

A)  12 ghz
B)  25 ghz
C)  30 ghz
D)  24 ghz

Question 19

A major disadvantage of klystron amplifier is:

Accepted Answer

A)  low power gain
B)  low bandwidth
C)  high source power
D)  design complexity

Question 20

If the RMS peak current in an IMPATT diode is 700 mA and if DC input power is 6 watt, with the load resistance being equal to

Accepted Answer

A)  10.1 %
B)  10.21 %
C)  12 %
D)  15.2 %

Exam 5: Microwave Devices and Their Operation: Gunn Diodes, Impatt Diodes, Klystron Tubes

The resonant frequency of an IMPATT diode is given by:

In Gunn diode oscillator, the Gunn diode is inserted into a waveguide cavity formed by a short circuit termination at one end

Magnetrons are microwave devices that offer very high efficiencies of about 80%.

The klystron tube used in a klystron amplifier is a __________type beam amplifier.

The production of power at higher frequencies is much simpler than production of power at low frequencies.

The frequency of oscillation in Gunn diode is given by:

Klystron amplifiers have high noise output as compared to crossed field amplifiers.

The number of semiconductor layers in IMPATT diode is:

If the critical field in a Gunn diode oscillator is 3.2 KV/cm and effective length is 20 microns, then the critical voltage is:

In crossed field tubes, the electron beam traverses the length of the tube and is parallel to the electric field.

An essential requirement for the BARITT diode is that the intermediate drift region be completely filled to cause the punch through to occur.

__________ is a single cavity klystron tube that operates as on oscillator by using a reflector electrode after the cavity.

Microwave tubes are power sources themselves at higher frequencies and can be used independently without any other devices.

The material used to fabricate IMPATT diodes is GaAs since they have the highest efficiency in all aspects.

IMPATT diodes employ impact ionization technique which is a noisy mechanism of generating charge carriers.

In a Gunn diode oscillator, the electron drift velocity was found to be 107 cm/second and the effective length is 20 microns, then the intrinsic frequency is:

__________ is a microwave device in which the frequency of operation is determined by the biasing field strength.

If the length of the intrinsic region in IMPATT diode is 2 µm and the carrier drift velocity are 107 cm/s, then the nominal frequency of the diode is:

A major disadvantage of klystron amplifier is:

If the RMS peak current in an IMPATT diode is 700 mA and if DC input power is 6 watt, with the load resistance being equal to