## Anna University Chennai B.E ECE 05th Semester EC2305 EC6503 Transmission Lines and Waveguides May June 2012 Past Exam Paper Free Download

Anna University ChennaiQuestion Paper Code:

B.E./B.Tech DEGREE EXAMINATION, MAY JUNE 2012

Fifth Semester

Electronics and Communication Engineering

EC2305 Transmission Lines and Waveguides

(Regulations 2008)

Time: Three Hours

Maximum: 100 Marks

Question Paper Type: Past Exam Papers

Answer ALL questions.

PART-A

1. Write the relationship between neper and decibel.

2. Write the disadvantages of constant k filter?

3. Draw the equivalent circuit of a unit length of a transmission line?

4. What is meant by infinite line?

5. Write the disadvantages of single stub matching?

6. Write the relationship between SWR and reflection coefficient?

7. Write maxwell’s equations?

8. What is meant by dominant mode? What is the dominant mode for parallel plate wave guide?

9. Write the expression for the wave impedance and guide wavelength for TEM mode?

10.What is the dominant mode of a rectangular waveguide? Why?

PART-B (5 x 16 = 80 marks)

11.a) calculate the values of the inductor and capacitor of a prototype constant k low pass filter composed of ∏ section to operate with a terming load of 600 ohms and to have a cut off frequency of 3KHz. Construct a band stop constant k filter?

(or)

b). discuss the characteristics of symmetrical network? Design an m derived T section low pass filter having cut off frequency fc= 1000 Hz design impedance Rk=600ohms and frequency of infinite attenuation f∞=1050 Hz.

12.A) derive the general solution of a transmission line terminated with any load impedance ZR. A transmission line has the following constants R=10.4ohm,L=3.66Mh,C=0.00835 µF and G=0.08 ohms. Calculate its characteristics impedance, attenuation and phase constant and phase velocity.

Or

b) i)A low loss transmission line of 100 ohms characteristic impedance is connected to a load of 200 ohm. Calculate the voltage reflection coefficient and the standing wave ratio.

ii) discuss the theory of open and short circuited lines with voltage and

current distribution diagram and also get the input impedance expression.

13. A)(i) An ideal loss less quarter wave transmission line of characteristics impedance 60 ohms is terminated in a load impedance ZL. Give the value of the input impedance of the line when ZL=0, ∞ and 60 ohm.

ii) write the concept of single stub double stub matching?

Or

b) i) A 100ohm, 200 m long loss less line transmission line operators at 10 MHz and its terminated into an impedance of 50-j200 ohm the transit time is 1µs. determine the length and location of short circuited stub line.

14.A) i) discuss the transmission of TM waves between parallel planes.

ii) write the instantaneous field expression for TM1 mode in parallel plane waveguides.

Or

b) i) discuss the transmission of TE waves between parallel planes.

ii) sketch the field lines of TE1 mode in parallel plane waveguides.

15.A) i) discuss the characteristics of TM waves in circular waveguides.

ii) A 10 GHZ signal is to be transmitted inside a hollow circular conducting pipe. Determine the inside diameter of the pipe line such that its lowest cut off frequency is 20% below this signal frequency.

Or

b) i) discuss the principle of rectangular cavity resonator.

ii) determine the dominant mode and their frequencies is an air filed rectangular cavity resonator for

a>b>d

a>d>b and

a=b=d

where a, b, d are dimension is the x, y, z directions respectively.

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