SRM University 2007 B.Tech Electronics and Communications Engineering BANK : TRANSMSSION LINES AND WAVES GUIDES - Question Paper

measured in the line is three and the position of current maxima closest to the load is 1 5th
wavelength away from the load. compute the value of load Impedance.
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. The VSWR measured on UHF transmission line working at a frequency of 300 MHz is obtained to be
2.If the distance ranging from load and voltage minimum is 0.8 meter, compute the value of load
Impedance.
8. 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 d) shortest length of line for which impedance
is purely resistive and e) the value of this resistance.

TLW
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 is the disadvantage of quarter wave line?
4. What are the applications of quarter wave line?
5. What is a stub?
6. What are the advantages of stub matching?
7. What are the kinds of stub matching?
8. Mention the need for impedance matching.
9. What are the disadvantages of single stub matching?
10. Briefly discuss about single stub matching?
11. Briefly discuss about double stub matching?
12. What are the advantages of double stub matching over single stub matching?
13. What is normalization of impedance?
14. What is smith chart? What is the distance around smith chart?
15. What are the 2 set of circles in smith chart and mention its center and radius.
16. What is the significance of R=1 circle in the smith chart?
17. What is the centre and radius for constant resistance circle?
18. What is the centre and radius for constant reactance circle?
19. What are the properties of smith chart?
20. What are the applications of smith chart?
21. What is the distance ranging from Imax & Imin and Vmax & Vmin?
22. What is meant by normalized smith chart?
23. What are constant S- circles?
24. Using Smith chart obtain the sending impedance of a line with negligible losses when Zo=55ohms
and the load impedance is 115+j75 ohms. Length of the line is 1.183 wavelengths.

Earning:   Approval pending.