R16 SET - 1

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III B. Tech I Semester Regular/Supplementary Examinations, October/November - 2019

ANTENNA AND WAVE PROPAGATION

(Electronics and Communication Engineering)

Time: 3 hours Max. Marks: 70

Note: 1. Question Paper consists of two parts (Part-A and Part-B)

2. Answer ALL the question in Part-A

3. Answer any FOUR Questions from Part-B

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PART –A (14 Marks)

1. a) What is the difference between E-plane and H-plane pattern? [2M]

b) Calculate the radiation resistance of half wave dipole. [2M]

c) What are the advantages of Binomial arrays? [2M]

d) Mention the properties of patch antennas. [3M]

e) Give the applications of horn antenna. [3M]

f) In which frequency range ground wave propagation is useful? [2M]

PART –B (56 Marks)

2. An antenna with a radiation resistance of 48 , a loss resistance of 2 , and a

reactance of 50 is connected to a generator with open circuit voltage of 10 V

and internal impedance of 50 via /4 long transmission line with characteristic

impedance of 100 .

i) Draw equivalent circuit.

[14M]

ii) Determine power supplied by generator, and

iii) Determine power radiated by antenna.

3. a) A short antenna of height h=l/2 is mounted on a conducting plane. Show that its

radiation resistance is one-half that of a short dipole antenna of length l and

carrying the same current.

[7M]

b) Compare monopole antennas and dipole antennas.

[7M]

4. a) Write short notes on Broadside arrays and End fire arrays. [7M]

b) Draw the radiation pattern of 8 – isotropic elements fed in phase, spaced /2 apart

with the principle of pattern multiplication.

[7M]

5. a) Explain about salient features of Microstrip Antennas. [7M]

b) What are the advantages and limitations of Microstrip antennas? Explain.

[7M]

6. a) List out the differences between active and passive corner reflectors. [7M]

b) With reference to paraboloids, explain the following:

i) f/D ratio

ii) Spill over and aperture efficiency

iii) Front to back ratio

iv) Types of feeds.

[7M]

7. a) Describe briefly the salient features of ground wave propagation. [7M]

b) Explain the “wave tilt of surface waves” in ground wave propagation. [7M]

*****

SET - 1 R16 Code No: R1631045

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1. a) Define the beam width of an antenna. [2M]

b) Find the effective area of half wave dipole operating at 200 MHz which has a

directivity of 1.644.

[2M]

c) What is the principle of pattern multiplication? [2M]

d) What happens if length of the wire in travelling wave antenna increases? [3M]

e) Explain why an antenna using a parabolic reflector is likely to be highly directive

receiving antenna?

[3M]

f) In which frequency range Sky wave propagation is useful? [2M]


2. a) With the help of neat diagrams, explain the principle of radiation mechanism in

antennas.

[7M]

b) A source has a constant power pattern limited to top half of the hemisphere only.

Find its directivity and effective area.

[7M]

3. a) An infinitesimal electric dipole is centered at the origin and lies along z-axis. Find

the far –zone electric and magnetic fields radiated.

[7M]

b) An infinitesimal electric dipole is centered at the origin and lies on the x-y plane

along a line which is at an angle of 450 with respect to the x-axis. Find the far –zone

electric and magnetic fields radiated.

[7M]

4. a) Show that the directivity can be improved by using n elements in broadside or end

fire array.

[7M]

b) Prove that the level of secondary lobe is -13.5 dB below that of major lobe in a

uniform linear array.

[7M]

5. a) Sketch the typical geometry of a helical antenna radiating in axial mode. List out all

its parameters and basic characteristics.

[7M]

b) Explain the differences between travelling wave antenna and standing wave antennas.

[7M]

6. a) Explain the principle of formation of images in an active corner reflector antenna.

Hence sketch the image formation for a 90o corner reflector. Obtain array factor for

90o corner reflector.

[7M]

b) What is the principle of equality of path length? How is it applicable to Horn

antennas? Obtain an expression for the directivity of a pyramidal horn in terms of its

aperture dimensions.

1 of 2

[7M]

SET - 2 R16 Code No: R1631045

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7. a) List out the modes of propagation and their frequency ranges for radio waves. Show

that an approximate estimate for the magnitude of electric field strength at VHF and

above is given by 240∗I∗π∗h1∗h2

λd2 .

where I - current in the λ/2 transmitting aerial;

h1, h2 - heights of Transmitting and Receiving antennas;

d - direct distance between aerials;

λ - wavelength.

Specify the assumptions made for the validity of the above expression.

[7M]

b) Write a short notes on

i) MUF

ii) Virtual Height

iii) Wave tilt

iv) Multi hop Transmission.

[7M]

*****

SET - 2 R16 Code No: R1631045

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1. a) An antenna has directive gain of 50 dB. Find the effective aperture of the antenna. [2M]

b) Calculate the radiation resistance of a quarter wave monopole. [2M]

c) What is the use of antenna array? [2M]

d) What is the advantage of terminating travelling wave antenna at one end other

than feed?

[3M]

e) What is zoning for Lens antenna? [3M]

f) In which frequency range space wave propagation is useful? [2M]


2. a) The normalized radiation intensity of an antenna is rotationally symmetric in and

it is represented by 𝑈 =

1 0 ≤ 𝜃 < 300

0.5 300 ≤ 𝜃 < 600

0.1 600 ≤ 𝜃 < 900

0 900 ≤ 𝜃 < 1800

What is the directivity (above isotropic) of antenna in dB?

[7M]

b) Derive the relationship between effective aperture area and gain of antenna.

[7M]

3. a) Calculate effective length and effective aperture area of antenna whose radiation

resistance is 73 Ω.

[7M]

b) Derive the expression for power radiated and find the radiation resistance of a half

wave dipole.

[7M]

4. a) Find the radiation pattern of uniform linear array of four isotropic elements fed in

phase, spaced /2.

[7M]

b) Find the radiation pattern of linear array of four isotropic elements fed in phase,

spaced /2 and amplitude ratio of excitation sources is in the ratio 1:3:3:1.

[7M]

5. a) Describe the characteristics of long wire travelling wave antennas; sketch their

patterns for different lengths.

[7M]

b) Explain the design considerations for monofilar helical antennas in various modes.

[7M]

6. a) With neat set up, explain the absolute method of measuring the gain of an antenna. [7M]

b) Discuss Dielectric and metal Lens Antennas and their applications. [7M]

7. a) Derive the relationship between MUF and critical frequency. [7M]

b) Determine the change in the electron density of E-layer when the critical

frequency changes from 4 MHz to 1 MHz between mid-day and sun-set.

[7M]

*****

SET - 3 R16 Code No: R1631045

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1. a) Draw the radiation pattern of omni-directional antenna. [2M]

b) Why the effective length of linear antenna is less than physical length. [2M]

c) Define array factor. [2M]

d) What is the difference between resonant and non-resonant antenna. [3M]

e) Explain how the efficiency of parabolic reflector affected by spillover. [3M]

f) Define MUF? [2M]


2. a) What is the difference between transmission line and dipole antenna. [3M]

b) Sketch and comment on the current distributions and radiation patterns of

vertical antennas of length /2, , 3/2, 2.

[7M]

c) Write short notes on antenna field zones.

[4M]

3. a) Compare far fields of small loop and short dipole. [7M]

b) Prove that the radiation field of a half wave dipole is zero in the direction of its

axis. Sketch the radiation diagram. Calculate HPBW.

[7M]

4. a) What is Yagi-uda Antenna? Explain the construction and operation of Yagi-uda

Antenna. Also explain its general characteristics?

[7M]

b) Explain the significance of folded dipole antenna.

[7M]

5. a) Explain the principle of operation in V-antenna. [7M]

b) What are the 3 independent parameters to be considered in design of Rhombic

antenna? Write down the design equations.

[7M]

6. a) How will you feed a parabolic reflector antenna? Explain aperture blockage and

offset feed.

[7M]

b) Explain the principle and operation of Cassegrain antenna with a neat diagram. [7M]

7. a) Explain Duct propagation in detail. [7M]

b) Find the range of LOS system when the receive antenna and transmit antenna

heights are 10 m and 100 m respectively. Take the effective earth’s radius into

consideration.

[7M]

*****

SET - 4 R16 Code No: R1631045

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OPERATING SYSTEMS

(Common to Computer Science and Engineering, Information Technology)





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1. a) Explain the importance of Real-Time Embedded systems. [2M]

b) Define Cooperating process? What is the environment need in Cooperating

processes?

[3M]

c) What is Critical Section Problem? [2M]

d) Write the difference between internal and external fragmentation. [2M]

e) Define the Safe, unsafe, and deadlock state spaces. [3M]

f) List the components of LINUX? [2M]


2. a) What is meant by interleaving and overlapping with respect to multi

programming and multi processing? Explain. (Assume system have two user

processes).

[8M]

b) Explain the Time-shared operating system.

[6M]

3. For the processes listed below, evaluate Average Waiting Time and Average

Turnaround Time for: i) FCFS ii) SJF iii) SRT iv) Non-Preemptive Priority

v) Preemptive Priority vi) RR(Q=2).

Processes A.T B.T Priority

A 0.0000 5 4

B 2.0001 4 2

C 2.0001 2 6

D 4.0001 4 3

[14M]

4. a) What is paging? Explain its structure for 32 -byte memory with 4-byte pages. [6M]

b) What is effective access time? Compute it for 70% hit ratio, 20 ns to search

TLB and 100 ns to access memory. Observe the difference when it is changed

to 90% hit ratio.

[8M]

5. a) Explain the usage and structure of monitors with an example. [6M]

b) Explain Banker's deadlock-avoidance algorithm with an illustration.

[8M]

6. a) List out the various methods for free-space management and explain them. [6M]

b) Give a brief note on Disk scheduling algorithms.

[8M]

7. a) Explain Android Process Management. [7M]

b) Explain IPC mechanism in LINUX. [7M]

*****

SET - 1 R16 Code No: R1631055

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OPERATING SYSTEMS






~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


1. a) What are Operating-System Services? [2M]

b) Identify the situations for Preemption of a process. [2M]

c) Define Busy Waiting? How to overcome busy waiting using Semaphore

operations.

[3M]

d) What is Deadlock? [2M]

e) Write short note on demand paging. [3M]

f) What are the various attributes that are associated with an opened file? [2M]


2. a) Explain different categories of System calls with suitable examples. [7M]

b) Explain briefly Layered Operating system structure with neat sketch.

[7M]

3. a) What are the differences between user-level threads and kernel-level threads? [7M]

b) Consider the following four processes represented as (Process, Arrival Time,

Burst Time) with the length of CPU burst in milliseconds.

( P1, 0, 10), (P2, 1, 7), (P3, 2, 13), (P4, 3, 11) . Using preemptive SJF

scheduling: i) Draw Gantt chart. ii) Calculate average waiting time.

[7M]

4. a) Given memory partitions of 500 KB, 100 KB, 200 KB, 300 KB, and 600 KB (in

order), how would each of the first-fit, best-fit, and worst-fit algorithms place

processes of 212 KB, 417 KB, 112 KB and 426 KB (in order)? Which algorithm

makes the most efficient use of memory?

[7M]

b) Consider the reference string: 7, 0, 1, 2, 0, 3, 0, 4, 2, 3, 0, 3, 2, 1, 2, 0, 1, 7, 0, 1 for

a memory with three frames. Trace FIFO, optimal, and LRU page replacement

algorithms.

[7M]

5. a) Write about Characterization of deadlock by resource allocation graph. [7M]

b) What is semaphore? Why it is important? Suggest the solution for bounded buffer

problem with semaphores.

[7M]

6. a) Discuss in detail about different file access methods. [6M]

b) Differentiate SCAN, C-SCAN and LOOK, C-LOOK disk scheduling algorithms

with an example.

[8M]

7. a) Explain process synchronization in Linux? [7M]

b) Explain Dalvik virtual machine in Android? [7M]

*****

SET - 2 R16 Code No: R1631055

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OPERATING SYSTEMS






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1. a) Define Operating System. [2M]

b) Define System Call? List out any four Process Control System Calls. [3M]

c) What are the functions of mutex semaphore? [2M]

d) Discuss the usage of wait-for graph method. [3M]

e) What is meant by hit ratio? Explain. [2M]

f) Define boot block. How it initiated from disk? [2M]


2. a) Distinguish between client-server and peer-to-peer models of distributed

systems.

[7M]

b) Explain the Dual-Mode operation of an operating system.

[7M]

3. a) What is IPC? Explain in detail the inter process communication models. [7M]

b) Perform Non-Preemptive CPU scheduling algorithms on the given snapshot

and analyze their performance:

Process Arrival Time Burst Time

1 0 3

2 2 6

3 4 4

4 6 5

5 8 2

[7M]

4. a) What is a page fault? Explain the steps involved in handling a page fault with a

neat sketch.

[7M]

b) Explain the concept of segmentation in detail.

[7M]

5. a) Consider the following and find out the possible resource allocation sequence

with the help of deadlock detection algorithm processes: p0, p1, p2, p3, p4,

Resources A, B, C Allocation [0 1 0, 2 0 0 , 3 0 3, 2 1 1, 0 0 2]

Max[0 0 0, 2 0 2, 0 0 0, 1 0 0, 0 0 2] Available[0 0 0].

[8M]

b) What is critical section problem? Explain about requirements that must satisfy for a solution to the critical-section problem.

[6M]

6. a) Briefly explain about single-level, two-level and Tree-Structured directories. [7M]

b) Explain and compare the FCFS and SSTF disk scheduling algorithms.

[7M]

7. a) Discuss the LINUX components system. [7M]

b) Explain the architecture of Android OS. [7M]

*****

SET - 3 R16 Code No: R1631055

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OPERATING SYSTEMS






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1. a) Explain how multiprogramming increases the utilization of CPU? [2M]

b) Define short-term, medium-term, and long-term scheduling. [3M]

c) Distinguish between counting and binary semaphores. [2M]

d) Define dead locks with example. [3M]

e) Explain the bit vector representation of free space management. [2M]

f) What is Android Software? [2M]


2. a) List and briefly describe types of operating systems. [7M]

b) Write about monolithic kernel, layered kernel, and micro kernel structures of

operating systems.

[7M]

3. a) Explain different process states with neat sketch. [7M]

b) Explain the Round Robin scheduling algorithm with a suitable example.

[7M]

4. a) What is Thrashing? What is the cause of Thrashing? How does the system detect

Thrashing? What can the system do to eliminate this problem?

[7M]

b) Consider the following page reference string:

1, 2, 3, 4, 2, 1, 5, 6, 2, 1, 2, 3, 7, 6, 3, 2, 1, 2, 3, 6

How many page faults would occur for the optimal page replacement algorithm,

assuming three frames and all frames are initially empty.

[7M]

5. a) Explain about software-based Peterson’s solution to the critical-section problem. [7M]

b) What are the necessary conditions for a Deadlock? Discuss.

[7M]

6. a) Explain the following concepts with respect to file: [15]

i) File operations ii) File Structures iii) File Types.

[7M]

b) Discuss in detail the file allocation techniques: Sequential, Indexed and Linked.

[7M]

7. a) Explain life cycle of android application. [7M]

b) Discus about interrupt mechanism in LINUX. [7M]

*****

SET - 4 R16 Code No: R1631055

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R16 SET - 1