Microwave Engineering (EC-702 (A)) - Important Questions

Explain the dominant and higher-order modes in stripline structure.

Explain the structure, principle of operation, and electron beam-RF field interaction mechanism in a TWT amplifier with neat sketch.

Draw the structure and explain the working principle / velocity modulation process of a two-cavity klystron amplifier and its applications.

Explain the construction and working of a reflex klystron including its mode curve/characteristics.

Explain the advantages/introduction and practical applications of microwaves.

Derive the expressions for effective dielectric constant and characteristic impedance of a microstrip line.

Derive a general bandwidth relation for microstrip and rectangular waveguides.

Explain the types and mechanism / working principle of magnetron oscillator including pi-mode operation with diagram

Give a brief comparison of microstrip lines and slot lines with suitable examples.

Explain the principle of operation, Gunn effect, bulk properties giving negative resistance and domains of operation of a Gunn diode

Write short notes on microwave devices including Gunn oscillator, TWT amplifier, BARITT, waveguide tee junction and tuned detectors

Explain the working principle and characteristics of a Schottky barrier diode. Discuss its use as a microwave mixer and detector.

Describe the working of a microwave BJT, its frequency limitations and applications.

Derive and explain Manley Rowe power relation.

State the basic operating principle of IMPATT and TRAPATT diodes.

What are the different solid state microwave sources use in industries? Explain its practical uses in today's world.

Derive a relation for frequency multipliers. Discuss its operating principle to be use in different microwave devices.

Derive basic relations for microwave BJT and FET circuits.

Discuss the various modes of operation of Tunnel diode and Gunn diode

Derive the expression for Voltage Standing Wave Ratio (VSWR) in terms of reflection coefficient

Define the scattering matrix and derive the general form for a reciprocal and lossless two-port microwave network.

State and explain the properties of the scattering matrix for a reciprocal network.

Explain the construction and working of a Slotted Line. How is it used to determine VSWR, wavelength and impedance?

Explain the construction and working of a Matching Network. Describe any two matching techniques used in microwave circuits.

Explain the principle and working of a VSWR meter with an example

Discuss the network analyzer and its use in measurements.

Explain why Z, Y, h and ABCD parameters are difficult to measure at microwave frequencies and describe S-parameters for a multi-port network with properties.

Given two-port S-parameters, test for reciprocity and losslessness and compute return loss under specified termination.

Derive and interpret S-parameters for microwave circuits.

Explain the structure and working principle of a YIG resonator, including its frequency tuning characteristics and applications in microwave circuits.

What is a magic Tee (matched hybrid Tee) junction? Derive its scattering matrix, showing how it combines E-plane and H-plane tee properties.

What are directional couplers? Explain their basic derived parameters such as coupling, directivity, isolation and insertion loss.

Describe the design and working of single-section and multi-section impedance transformers and how multi-section design increases bandwidth.

Discuss some of the properties of ferrites, isolators and phase shifters.

Explain the coupling factor and directivity of a four-port directional coupler and derive the S-matrix for a completely matched four-port directional coupler.

Mentioned the symbol and schematic diagram of microwave circulator. Explain the working of the same using geometry containing two magic tee and one phase shifter along with its simplified S-matrix.

Explain the importance of impedance transformers in microwave devices with practical applications.

Draw and explain the block diagram of frequency converters using varactor diodes.

Describe the working principle of a microwave mixer, roles of LO, RF and IF signals, and conversion loss.

Explain how oscillators are designed using S-parameters. Derive the oscillation condition in terms of reflection coefficients and feedback.

Draw and explain the block diagram of frequency converters using Schottky diodes.

Explain the diode phase shifter. Discuss the principle of broadband and tuned detectors.

Write a short note on any two:

Discuss the general representation of EM field in terms of TEM, TE and TM components.

Write and explain the classification of different waveguide structures, also explain its operating principle.

A rectangular waveguide with dimension of $3\times 2$ cms operates in TM11 mode at $10$ GHz. Determine the characteristic wave impedance.

Discuss some of the properties of Dominant mode.

An open wire transmission line has the following primary constants $R = 4 \Omega/\text{km}$, $L = 2.5 \text{ mH/km}$, $C = 0.009 \text{ } \mu\text{F/km}$, $G = 0.29 \text{ } \mu\text{mho/km}$ and Frequency of operation is $1 \text{ kHz}$. Determine the following parameters

A rectangular waveguide with dimension of $3 \times 2 \text{ cms}$ operates in $TM_{11}$ mode at $10 \text{ GHz}$. Determine the characteristic wave impedance.

For the dominant mode of operation in an air filled circular waveguide of inner diameter $4 \text{ cms}$. Find :

An air-filled circular waveguide has a radius of $2 \text{ cm}$ and is to carry energy at a frequency of $10 \text{ GHz}$. Find all the TE and TM modes for which energy transmission is possible.

A rectangular waveguide with dimension of $3\times 2$ cm operates in TM11 mode at $10$ GHz. Determine the characteristic wave impedance.