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)