Microwave Engineering — Summer 2019

Discuss advantages of microwave frequencies over lower frequencies; also explain some areas of microwave application.

Define the following terms

TEM wave, ii) TE wave, iii) TM wave, iv) HE wave, v) Characteristic Impedance, vi) Reflection coefficient, vii) Input impedance.

Explain the working principle of ‘Magic Tee’ in detail with S-matrix and neat diagram.

Determine the cut-off wavelength for the dominant mode in a rectangular waveguide of breadth 10 cm. For a 2.5 GHz signal propagated in this waveguide in the dominant mode; Calculate the guide wavelength, the group and the phase velocities.

Atwo cavity Klystron amplifier has the following parameters. Beam voltage: Vo = 900 V, Beam current: Io = 30mA, Frequency: f= 8 GHz, Gap spacing in either cavity: d= 1 mm, Spacing between centers of cavities: L= 4 cm, Effective shunt impedance: Rsh = 40kΩ. Determine,

The electron velocity, ii) The d.c. electron transit time, iii) The input voltage for maximum output voltage, iv) The voltage gain in decibels.

Explain functioning of four ports circulator with neat schematic diagram.

Describe working principle of Helix Travelling Wave Tube with neat diagram.

Explain operational principle, V-Icharacteristics, construction, advantages and disadvantages of IMPATT diode with neat diagram.

Describe all the characteristics of Smith chart.

Write a short note on Varactor diodes.

De r i v e three expressions for maximum radar range, Rmax.

Draw and explain block diagram of ‘Pulsed Radar System’.

Prove that reflection coefficient(ρ) is dependent on characteristic impedance (Z ) and load impedance ( Z ),also specify how their different values affects ρ. O L

Explain function of cylindrical magnetron with neat diagram.

Describe MTI Radar functions with neat block diagram.

Explain various radar display methods with neat diagram.

Derive an expression for characteristics impedance and quality factor of microwave strip lines.