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Electronics and Communication Engineering - Microwave Communication

Exercise : Microwave Communication - Section 1
21.
Which of the following parameters is negligible in transmission lines?
R
L
C
G
Answer: Option
Explanation:

Shunt conductance can be neglected in most of calculations.

22.
The width of a radio beam from a 1 m diameter parabolic antenna at 10 GHz is about
100°
50°
5°
1°
Answer: Option
Explanation:

.

23.
The diagram to show distance time history of electrons in klystron amplifier is called
apple gate diagram
asynchronous diagram
bunching diagram
velocity modulation diagram
Answer: Option
Explanation:

Applegate diagram is distance time plot.

24.
Impedance level of Impatt diodes is generally lower than that of Gunn diodes
True
False
Answer: Option
Explanation:

An Impatt diode has n+ - p - i - p + structure and is used with reverse bias.

It exhibits negative resistance and operates on the principle of avalanche breakdown.

Impatt diode circuits are classified as broadly tunable circuit, low Q circuit and high Q circuit.

The impedance of Impatt diode is a few ohms. The word Impatt stands for Impact Avalanche Transit Time diode.

The features of Impatt diode oscillator are : frequency 1 to 300 GHz, Power output (0.5 W to 5 W for single diode circuit and upto 40 W for combination of several diodes), efficiency about 20%.

Its applications include police radar systems, low power microwave transmitter etc.

25.
A quarter wave line open circuited at far end behaves as
inductance
L and C in parallel
capacitance
L and C in series
Answer: Option
Explanation:

A quarter wave line o.c. at far end behaves as a series tuned circuit.

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