This set of RF & Microwave Circuit Design Multiple Choice Questions & Answers (MCQs) focuses on “Smith Chart”.

1. Any passively realizable reflection coefficient can be plotted as a unique point on the smith chart. This statement implies that:

a) Reflection co-efficient less than or equal to 1 can be plotted

b) Reflection co-efficient greater than or equal to 1 can be plotted

c) Transmission co-efficient has to be less than or equal to one for the point to be located

d) T=Г+1

2. Reflection coefficient of a transmission line in its polar form can be represented as:

a) ┌=|┌|e^{jθ}

b) ┌=|┌|e^{jθ-1}

c) ┌=|┌|e^{jθ+1}

d) ┌=|┌|e^{jθ+α}

3. Smith chart is based on the polar plot of:

a) Reactance

b) Voltage

c) Current

d) Voltage reflection co-efficient

4. If the characteristic impedance of a ƛ/2 transmission line is 50 Ω and reflection coefficient 0.3, then its input impedance

a) 26.92 Ω

b) 30 Ω

c) 40 Ω

d) 34.87 Ω

5. If the input impedance of a ƛ/2 transmission line is 100 Ω with a voltage reflection coefficient of 0.344, then the characteristic impedance of the transmission line is:

a) 200 Ω

b) 100 Ω

c) 50 Ω

6. Normalized impedance of 1-j is:

a) In the upper half of the impedance smith chart

b) In the Lower half of the impedance smith chart

c) On the outer most circle of the smith chart.

d) On the horizontal line of the smith chart

7. If the normalized input impedance of a transmission line is 0.5 Ω, then he reflection coefficient of a ƛ/2 transmission line is

a) 0.3334

b) 0.5

c) 0.6667

d) 1

8. Normalized impedance of 0.3+j0.4 lies in the:

a) Upper half of the impedance smith chart

b) Lower half of the impedance smith chart

c) Horizontal line of the chart

d) None of the mentioned

9. If a transmission line of a characteristic impedance 100 Ω is terminated with a load impedance of 300+j200 Ω, then the normalized load impedance is:

a) 1+j

b) 1-j

c) 3+2j

d) 2-3j

10. To get an admittance chart from an impedance chart:

a) Smith chart has to be rotated by 90⁰

b) Smith chart has to be rotated by 180⁰

c) Admittance chart cannot be obtained from the impedance chart anyway.

d) None of the mentioned

11. If the normalized load impedance of a transmission line is 0.3-j0.4 with a characteristic impedance of 50 Ω, then the load impedance is:

a) 15-j20

b) 15+j20

c) 1-j

d) 0.3-0.4j