SRM University 2007 B.Tech Electronics and Communications Engineering BANK FOR Transmission Lines and Wave Guides - Question Paper

b) Draw the impedance variation of open and short circuited RF line.
3. Explain the method of Power and Impedance measurement on a zero dissipation Line.
4. Explain how Standing Wave Ratio and Wavelength can be measured in a transmission line.
5. An UHF Transmission line of Zo=75/_0 ohms is terminated in an unknown load. The VSWR measured in the line is three and the position of voltage minima closest to the load is 1 5th wavelength away from the load. compute the value of load Impedance, VSWR.
6. The terminating load of UHF transmission line (Zo=50/_0 ohms) working at 300 MHz is 50+j50 ohms. compute the VSWR and the position of the voltage minimum closest the load.
7. A lossless 100 Ohms transmission line is terminated in 200 +j200 Ohms . obtain a) Voltage reflection coefficient b) VSWR c) Impedance 0.375? from load
UNIT – III IMPEDANCE MATCHING AT HIGH FREQUENCIES
PART-A
1. Give the expression for input impedance of a quarter wave line ?
2. What will be the characteristic impedance of a quarter wave lines to match 2 transmission lines having characteristic impedance of 100,75 ?
3. What are the applications of quarter wave line?
4. What is a stub?
5. What are the advantages of stub matching?
6. What are the kinds of stub matching?
7. Mention the need for impedance matching.
8. What are the disadvantages of single stub matching?
9. What is normalization of impedance?
10. What is smith chart? What is the distance around smith chart?
11. What are the 2 set of circles in smith chart and mention its center and radius.
12. What is the significance of R=1 circle in the smith chart?
13. What is the centre and radius for constant resistance circle?
14. What is the centre and radius for constant reactance circle?
15. What are the applications of smith chart?`
16. What is the distance ranging from Imax & Imin and Vmax & Vmin?

PART-B
1. A transmission line of characteristic impedance Zo is terminated by ZR, derive the expression for the position of attachment and length of a short circuited stub.

2. Explain about the features and applications of Smith Chart.
3. (i) provide detail explanation about the quarter wave transformer
(ii) discuss about double stub matching in detail.

4. A low loss line with Zo = 70 ohms is terminated in an impedance ZR=115-j80 ohms. using smith chart obtain the following:
i. Standing wave ratio
ii. Maximum and Minimum line impedance

Earning:   Approval pending.