Question 1

The number of modes of operation for n type GaAs is:
A)two
B)three
C)four
D)five

Accepted Answer

GaAs (Gallium Arsenide) can operate in four modes: bulk, surface, quantum well, and quantum dot modes. These modes are determined by the dimensionality and confinement of charge carriers within the material.

Question 2

The free electron concentration in N-type GaAs is controlled by:
A)effective doping
B)bias voltage
C)drive current
D)none of the mentioned

Accepted Answer

Effective doping controls the free electron concentration in N-type GaAs, as doping introduces additional electrons into the material.

Question 3

The modes of operation of a Gunn diode are illustrated in a plot of voltage applied to the Gunn diode v/s frequency of operation of Gunn diode.

Accepted Answer

The modes of operation of a Gunn diode are typically illustrated in a plot of current versus voltage (I-V characteristics), not voltage versus frequency. The frequency of operation is determined by the physical dimensions and doping characteristics of the diode, not directly by the applied voltage.

Question 4

The mode of operation in which the Gunn diode is not stable is:
A)gunn oscillation mode
B)limited space charge accumulation mode
C)stable amplification mode
D)bias circuit oscillation mode

Accepted Answer

The Gunn diode is not stable in the Gunn oscillation mode because in this mode, it generates microwave frequencies by exploiting the negative differential resistance in its material, leading to oscillations that are inherently unstable.

Quiz 4: Antenna Arrays, Power Amplifiers, and Gunn Diodes

The number of modes of operation for n type GaAs is:

The free electron concentration in N-type GaAs is controlled by:

The modes of operation of a Gunn diode are illustrated in a plot of voltage applied to the Gunn diode v/s frequency of operation of Gunn diode.

The mode of operation in which the Gunn diode is not stable is: