Microwave Engineering Lab Viva Questions – Part 4

1) Even mode and odd mode analysis can be done if the network is..

a) Reciprocal

f) a & c

b) Lossless

c) symmetric

d) a & b

e) b & c

g)none.

Answer : [f] a & c

2) For a resistive four port and three port devices the amount of power lost at the junctions respectively.

a) 50 % , 65 %

b)67%, 50%

c) 33%, 67%

d) 67%, 33%

e) None

Answer : [b] 67%, 50%

3) The Isolation for port 2 and port 3 is present in.

a) Resistive T-Junction

d) H-plane T

b) Wilkinson power divider

e)Lossless T-junction

c) E-plane T

f)None

Answer : [b] Wilkinson power divider

4) The Percentage of power comes to port 2 in equal split Resistive power divider when input is given at port 1 is

a) 50%

b) 75%

c)25%

d) 15%

e)None

Answer : [c] 25%

5) In equal split lossless T-junction power divider, what would be the characteristic Impedance value of Quarter wave Transformer at port 2 match it to .

a) 0.707 Zo

b)Z0

c)1.712 Zo d) 2 Zo

e) None

Answer : [e] None

6) For a four port Directional coupler in which all ports are matched and input is given at port 1. Voltage at coupled port is 1V, Voltage at isolated port is 1mV, voltage at through port is 3V now what is coupling.

a) 8.5 dB

b) 13.8 dB

c) 10.6 dB

d) 20 dB

e) None

Answer : [d] 20 dB

7) We use ................property of ferrite material to make Isolator and circulator

a) Anisotropic

e) a, b &c

b) Non-linear

c)Non-homogenous

d)a & c

f)None

Answer : [a] Anisotropic

8) If we observe the graphical representation of the S-parameters (in the range of 0 to -50 dB) of equal split power divider with respect to frequency which parameter will dominant in graph.

a) S12

b)S11

c)S23

d)S22

e)None

Answer : [a] S12

9)If a network is reciprocal and lossless and s21 = 12∠90 0 is then find the return loss seen in port 1 if port two is terminated with matched load

a)1.5 dB

b) 3 dB

c)-3 dB

d)-1.5 dB

Answer : [b] 3 dB

10. Find reflection co-efficient at input port of a X-band air-filled Waveguide(Dimensions 1 * 0.5 inch) of length λ0 4 which is terminated by a load of 500 ohm ,frequency of operation is 10GHz

a) 0.243

b)0.033

c)0.818

d)Zero

Answer : [c] 0.818