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10000EC403122004

3. Efficiency of the amplifier, neglecting beam loading.
4. Beam loading conductance and show that it can be neglected.
Derive the output power and efficiency of a reflex klystron oscillator.
PART ‏تا‎

Answer any two full questions, each carries 15 marks.
Explain slow wave structures. Describe how the slow wave structure of a TWT
helps in bunching process.
Define the terms coupling coefficient (C), directivity (D) and isolation (1) of a
directional coupler. Determine these parameters in DB for a lossless directional
coupler with incident power 40mw, power at the coupling port is 10mw and
power at the decoupled port 0.1 mw.
Show that the magnitude of the velocity fluctuation of the electron beam is directly
proportional to the magnitude of the axial electric field in a helix TWT
Define S matrix. Explain the properties of S matrix.
Explain the constructional features of magic tees and derive its S Matrix
Explain different methods for measuring microwave power.
With a schematic describe the operation of a four-port circulator. Obtain the
simplified S matrix of a perfectly matched, lossless four port circulator.

PART C

Answer any two full questions, each carries 20 marks.
Explain Ridley—Watkins—Hilsum theory with the help of two valley model and
derive the conditions for negative resistance.
Show that the product of the maximum unambiguous range Ry, and the first
blind speed Vj is equal to 02/4.
A simple MTI delay line canceller is an example of time domain filter. Explain
Why?
Why the low noise front ends are necessary for a radar receiver? Describe the
utility of low noise front ends.
Explain the various limitations of microwave transistors. What are the main
assumptions made in power frequency limitations?
With neat diagram explain serial loading and parallel loading in tunnel diode.
How tunnel diode can be used as circulator?

Explain FM-CW Radar with the help of a block diagram

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