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Introduction to microwaves

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Cavity resonators

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Derivation of resonance frequency of rectangular wave guide

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Problems of Rectangular wave cavity resonator

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Principle and structure of Reflex Klystron

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Reflex Klystron

00:00 - Power output (P_ac)

03:04 - Efficiency of Klystron

06:09 - Admittance of Klystron

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Q1) A reflex klystron operates at the peak mode n=2 with V0 = 280 V, I0 = 22mA and signal voltage V1 = 30 V, Calculate

The input power 

The output power 

efficiency 

Q2) A reflex klystron is operated at 5 GHz with V0=1000 V and cavity gap 2 mm. Calculate the gap transit angle 

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Q3) A reflex klystron is operated under the following condition

V0 = 600 V, L=1 mm , Rsh = 15 KΩ , e/m = 1.759 x 1011 fr =9 GHz.

The tube is oscillating at fr at the peak of n = 2 mode or (3/4) mode. Assume that the transit time through the gap and beam loading can be neglected

Find the value of Repeller voltage ?

Find the direct current necessary to give a microwave gap voltage of 200 V ?

What is the electronic efficiency under this condition ?

Q4) A reflex klystron operates under the following conditions:

V0​  = 500 V, Rsh​  = 20 kΩ, f𝑟​  = 8 GHz, L = 1 mm is the spacing between Repeller and cavity. The tube is oscillating at f𝑟  at the peak on n = 2 mode or 1 3/4​  mode. Assume that the transit time through the gap and through beam loading effect can be neglected.

Find the value of Repeller voltage VR

Find the dc necessary to give microwave gap of voltage of 200 V

Calculate the electronic efficiency 

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00:00 - Magnetron introduction

01:38 - Principle & structure of magnetron oscillator

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Derivation of equation of electron motion

Hull cut off magnetic equation

Hull cut off voltage equation

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00:00 - Cyclotron angular frequency

04:34 - power output and efficiency

Q1) An X-band pulsed cylindrical magnetron has following parameters

 V0 = 30 kV, I0 = 30 A, B0 = 0.336 Wb/m2, a = 5 cm, b = 10 cm

Compute

a) The cyclotron angular frequency, b) The cut off voltage for a fixed B0

c) The cut off magnetic flux density for a fixed V0, Q2) An X0band pulsed conventional magnetron has following parameters

  V0 = 5.5 kV, I0 = 5 A, f = 10GHz, Gr = 2x10-4 ℧, Gl = 2.5x10-5 ℧, C = 2.5pF , DC = 0.002, Ploss = 18.5 kW 

Compute

a) The angular resonant frequency, b) The unloaded quality factor

c) The loaded quality factor, d) The external quality factor

e) The circuit efficiency, f) The electronic efficiency

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00:00 - Introduction to traveling wave tube (TWT)

03:14 -  Structure of TWT

07:39 - Working of TWT

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00:00 - Traveling wave - slow wave structure

06:17 - Traveling wave - Amplification process

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Traveling wave - convection current derivation

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00:00 - Travelling wave tube - Axial electric filed

05:47 -  Travelling wave tube - wave mode

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Travelling wave tube solved problem