Microwave Engineering

AIMS

To provide the students with an opportunity to develop knowledge, skill and attitude in the area of microwave & antenna with special emphasis on:
• microwave components
• wave guides
• microwave tubes
• microwave measurements
• microwave antenna
• semiconductor microwave devices
• propagation models

SHORT DESCRIPTION

Concept of microwave, Microwave components; Wave guide; Microwave tubes; Microwave measurements; Microwave antenna; Semiconductor microwave devices; Propagation models.

DETAIL DESCRIPTION

Theory:

1 Understand the concept of microwave.
1.1 Define the term microwave.
1.2 Mention the application of microwave with frequency range.
1.3 List the characteristics of microwave.
1.4 Mention the problems associated with conventional tubes at UHF.
1.5 Describe the characteristics of tubes for ultra high frequency.
1.6 Describe the basic principle of acron and disk seal tube.
2 Understand the concept of microwave components.
2.1 Describe the construction and function of basic microwave components, wave guide tees, magic tee, isolating device, adjustable phase shifter, hubrid ring (rat-race), coupling probes, couping loops, wave guide flanges, rotating joints, travelling detector, mode suppressors, irises, turing posts and screws.
2.2 Describe the working principle of wave meters.
2.3 Describe the working principle of directional couplers (DC).

2.4 Describe the constructions of isolators and circulators.
2.5 Describe the principle of isolators and circulators.
2.6 Describe the principle of operation of cavity resonator.
3 Understand the features of waveguide guide.
3.1 Define the term waveguide.
3.2 List the advantages of wave guide over coaxial line.
3.3 Mention different modes of a wave guide.
3.4 Describe phase velocity and group velocity in a wave guide.
3.5 Describe the field pattern of TE10, TE20, TM11 and TEM modes.
3.6 Explain the methods of mode excitation in rectangular wave guide.
3.7 Describe behavior, field pattern and disadvantages of circular waveguide.
4 Understand the features of klystron tube.
4.1 Describe the construction and operation of two cavity klystron tube.
4.2 Describe applegate diagram for klystron amplifier.
4.3 Describe the construction and operation of multi cavity klystron.
4.4 Mention the performance and application of multi cavity klystron.
4.5 Describe the construction and operation of reflex klystron tube.
4.6 Mention the performance and applications of reflex klystron.
5 Understand the features of magnetron and travelling wave tube.
5.1 Describe constructional features of cavity magnetron.
5.2 Describe the mechanism of oscillations in a magnetron.
5.3 Describe the construction and operation of travelling wave tube.
5.4 Mention performance, properties and applications of travelling wave tube.
6 Understand the basic concept of microwave measurements.
6.1 Describe the method of measurement of low microwave power by bolometer and microwave thermocouple.
6.2 Describe the method of measurement of medium and high microwave power by calorimeter wattmeter measuring system.
6.3 Describe the method of measurement of microwave frequency and wavelength.
6.4 Describe the method of measurement of standing wave ratio (SWR).
6.5 Describe the method of measurement of impedance.
6.6 Describe the method of measurement of attenuation.
7 Understand the features of microwave antennas.
7.1 Mention the characteristics of microwave antennas.
7.2 Describe the constructions of horn antennas.
7.3 Describe the operation of antennas with parabolic reflectors.
7.4 Describe the function of feed antennas.
7.5 Describe the operation of dielectric lens antenna.
7.6 Describe the construction and application of loop, modified loop and adcock antennas.
7.7 Describe the operation of horizontal and vertical log periodic aerials.
7.8 Describe the modern trends in aerial design and practice.
8 Understand the concept of semi conductor microwave devices.
8.1 Describe the construction, performance and application of microwave transistor.
8.2 Describe the construction and operation of varactor diode.
8.3 Describe the characteristic of varactor diode.
8.4 Describe the basic principle of parametric amplifiers.
8.5 Describe the constructional features and applications of gunn diode.
8.6 Describe the theory of microwave amplification by stimulated emission of radiation (Maser).
8.7 Describe the construction and performance of IMPATT (impact avalanche and transit time) diode.
9 Understand the propagation path loss and propagation models.
9.1 Mention the multipath characteristics of radio wave.
9.2 Describe the free space path loss with simple model.
9.3 Describe the path loss over a reflecting surface with simple model.
9.4 Define the term fade margin.
9.5 Describe the propagation models for the outside environment.
9.6 Describe the propagation models for indoor environment.

Practical:

1 Perform the measurement of the tuning range of a reflex klystron.
Select reflex klystron, power supply, klystron mounts detector & necessary meters, equipment and materials.
Connect the klystron tube and associated components properly.
Set up the signal detector.
Connect the power supply.
Set the tuning control at minimum.
Measure the frequency.
Measure the frequency for the maximum control.
Determine the tuning range.
2 Perform the measurement of the VSWR of a microwave signal for a given load.
Select a micro wave tube (klystron) and require apparatus & materials.
Connect the klystron, wave guide/slotted line, load and necessary equipment.
Switch on the power supply.
Adjust the controls properly.
Measure the VSWR.
3 Study the operation of two cavity klystron amplifier.
3.1 Select a klystron tube and required apparatus & materials.
3.2 Set up the apparatus and connect the circuit properly.
3.3 Switch on the power supply.
3.4 Apply known signal to the input.
3.5 Make necessary adjustment.
3.6 Measure the signal from output.
3.7 Determine amplification.
4 Study the operation of travelling wave tube amplifier.
4.1 Select the tube and required tools & materials.
4.2 Connect the circuit and equipment properly.
4.3 Switch on the power supply.
4.4 Apply known signal to the input.
4.5 Make proper adjustment.
4.6 Observe the output.
4.7 Determine the amplification.

5 Study the operation of magnetron tube oscillator.
5.1 Select the tube, required apparatus and materials.
5.2 Set up the equipment and connect the circuit.
5.3 Switch on the power supply.
5.4 Make proper adjustment.
5.5 Observe the output frequencies.
5.6 Determine the modes of the tube.
6 Perform the measurement of the klystron frequency by slotted selection method.
6.1 Select klystron supply, mount isolator, slotted section and required apparatus & materials.
6.2 Connect the circuit and set up equipment properly.
6.3 Switch on the power supply.
6.4 Make necessary adjustment.
6.5 Measure the frequency.
7 Perform the measurement of the directivity and coupling of a directional coupler (DC).
7.1 Select klystron supply, mount, isolator, directional coupler and required equipment & materials.
7.2 Set up the apparatus and connect the circuit.
7.3 Switch on the power supply.
7.4 Make proper adjustment.
7.5 Measure the coupling.
7.6 Measure the directivity.
8 Perform the drawing of radiation pattern of horn antenna in horizontal and vertical plane.
8.1 Select klystron supply, klystron mount, isolator two horn antenna, waveguide to coaxial adapter, etc.
8.2 Set up the apparatus and connect the circuits.
8.3 Switch on the power supplies.
8.4 Make proper adjustment.
8.5 Obtain data for horizontal and vertical plane.
8.6 Plot the radiation pattern.
9 Perform the verification of the properties of magic tee.
9.1 Select magic tee and required apparatus.
9.2 Set up the equipment and connect the circuit.
9.3 Switch on the power supply.
9.4 Make proper adjustment.
9.5 Observe the properties of magic tee.
10 Study the characteristics of parabolic dish antenna.
10.1 Select a dish antenna and required apparatus.
10.2 Select low noise blockdown (LNB) converter.
10.3 Set up the LNB and parabolic dish antenna.
10.4 Observe the characteristics of parabolic antenna.
11 Study the operation of varactor diode, gunn diode and IMPATT diode.
11.1 Select the necessary diode, required apparatus and materials.
11.2 Setup the equipment and connect the circuits.
11.3 Switch on the power supply.
11.4 Observe the input and output signals.
12 Perform the measurement of the microwave power.
12.1 Select required equipment, tools and materials.
12.2 Construct the circuit.
12.3 Switch on the power.
12.4 Make power adjustment.
12.5 Measure the microwave power.

* Visit a microwave station and prepare a report.

REFERENCE BOOKS

1. Communication System
– Kennedy
2. Microwave Engineering
– Sanyeeva Gupta
3. Radio Engineering
– M. L. Gupta.
4. Field’s and Waves in Communication Electronics
– SIMON RAMO

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