Microwaves & RADAR - Jun 2014

Electronics & Communication (Semester 5)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) Derive an expression for reflection coefficient and transmission coefficient in the transmission line(8 marks) 1 (b) Derive the relationship between SWR and reflection co-efficient.(6 marks) 1 (c) A telephone line has R-6 Ω/km, L=2.2 mh/km, C=0.005 μf/km and G=0.05 μ&mho/km. Determine Z₀, α, β and phase velocity at 1 KHz.(6 marks) 2 (a) Derive the field equation for TE modes in rectangular waveguide.(10 marks) 2 (b) A rectangular air filled copper waveguide with dimension 0.9×0.4 inch cross section and 12 inch length is operated at 9.2 GHz with a dominant mode. Find: i) Cut-off frequency; ii) Guide wavelength; iii) Phase velocity; iv) Characteristic impedance; v) The loss.(10 marks) 3 (a) With a neat sketch, explain the TRAPATT diode and draw its characteristics.(10 marks) 3 (b) Explain the parameteric amplifier with equivalent circuit. Give the advantages of parametric amplifier.(10 marks) 4 (a) Explain symmetrical z and y matrices for reciprocal network(6 marks) 4 (b) Which properties are common in s. z and y matrices?(6 marks) 4 (c) Derive an expression of the input reflection coefficient of a two port with mismatched load.(8 marks) 5 (a) Explain with a neat sketch a precision phase shift.(10 marks) 5 (b) With a neat sketch, explain the operation of magic tee. Also obtain the S matrix representation of the magic tee.(10 marks) 6 (a) Briefly explain dielectric losses, ohmic losses and radiation losses in microstrip lines.(10 marks) 6 (b) With a neat diagram, explain the operation of parallel strip line. Write the expression for distributed parameters, characteristic impedance and attenuation losses.(10 marks) 7 (a) Derive the simple radar range equation starting from the power density of isotropic antenna.(8 marks) 7 (b) Calculate the maximum range of a radar system which operates at 3 cm with a peak pulse power of 600kW if its minimum receivable power is 10³ W, the capture are of its antenna is 5m² and the radar cross sectional area of the target is 20m².(5 marks) 7 (c) What are the applications of radar?(7 marks) 8 (a) Explain single delay line canceller and frequency response of the single delay line canceller.(10 marks) 8 (b) With neat block diagram, explain the operation of MTI Doppler signal processor.(10 marks)