VALLIAMMAI ENGINEERING COLLEGESRM Nagar, Kattankulathur – 603 203 DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING QUESTION BANK VI SEMESTER EC 6602 – Antenna and Wave Propagation Regulation – 2013 Academic Year 2016 – 17 Prepared by Ms. N. Subhashini, Assistant Professor (SG)/ECE Ms. R.Birundha, Assistant Professor /ECE Mr. N. Rajesh, Assistant Professor/ECE Effective aperture. Summarize the types of Baluns and its applications. Polarization mismatch. VALLIAMMAI ENGINEERING COLLEGE SRM Nagar. Radiation Resistance. BTL 1 Remembering 3. Input Impedance. Review the types of an antenna. Assuming lossless. Discuss about retarded potential in antenna. BTL 1 Remembering 5. BTL 2 Understanding 9.direction BTL 1 Remembering at θ = 0˚. Folded dipole. estimate the power delivered to receiver. 11. Define Radio Antenna.FUNDAMENTALS OF RADIATION Definition of antenna Parameters .5 m2 and is located at a 15 km Line-of-sight distance from BTL 2 Understanding the transmitting antenna. Relate the Gain and Directivity of an antenna through proper expression. A radio link has a 15W transmitter connected to an antenna of 2. DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING QUESTION BANK SUBJECT : EC6602 – ANTENNA AND WAVE PROPAGATION SEM / YEAR: VI / III Unit I .Gain. Antenna noise temperature. Yagi array PART A Q. Matching-Baluns. Radiation from oscillating dipole. Half wave dipole. matched antennas. BTL 2 Understanding 10. Draw the 3D pattern of a directional antenna with maximum in z. What is an elementary dipole and how does it differ from the infinitesimal BTL 1 Remembering dipole? 6. BTL 2 Understanding 8. 4. List the antenna parameters. Define the term Half Power Beam Width. BTL 1 Remembering 7. BTL 1 Remembering 2.5 m2 effective aperture at 5 GHz.No Questions BT Competence 1. Directivity. Beamwidth. Kattankulathur – 603 203. Bandwidth. The receiving antenna has an effective aperture of 0. Solve the HPBW for an antenna with a field pattern given by BTL 3 Applying Eφ=Cos2φ for 0˚≤ φ ≤90˚ . Sketch the radiation pattern. (16) 6. Sketch the structure of Yagi Uda Array for a frequency of 200 MHz. BTL 4 Analyzing 15. Distinguish between power gain and directive gain. 19. Evaluate the efficiency and directivity (in dB) if the radiation resistance of BTL 5 Evaluating an antenna is 65 ohms and loss resistance is 10 Ohms. (16) 9. Demonstrate the principle of radiation from an oscillating electric dipole. (a) Antenna BTL 1 Remembering noise temperature (b) Bandwidth (c) Input Impedance (d) Effective aperture. Relate the surrounding temperature factors associated with the antenna temperature . Discuss in detail about the radiation from a small oscillating current BTL 2 Understanding element with the required E and H field quantities and diagrams. Define and explain in detail the following antenna parameters. through proper explanation and expression. Discuss the radiated fields of a center fed λ/2 dipole antenna with an BTL 2 Understanding appropriate expressions. Deduce the equation for “directivity from pattern”. Calculate the effective length of the element considering the voltage BTL 3 Applying induced by the application of an electric field of strength 2 volts / meter is 0. Show that the directivity of an antenna depends on the power radiated.12. (16) 5. What is Poincare sphere? List the types of Polarization of an antenna and BTL 1 Remembering explain in detail. BTL 6 Creating 20. (16) 7. BTL 3 Applying Derive the near field and far field expressions. Examine the total radiated power if the radial component of the radiated BTL 4 Analyzing power density of an antenna is given by Wrad = Wrâr = ârAosinθ / r2 (W/m2) where Ao is the peak value of the power density. BTL 3 Applying 14. 16. (16) 4. Explain the structure of a folded dipole antenna and find the radiation BTL 2 Understanding resistance and the admittance of the folded dipole. Select a proper method to match the impedance of the antenna and explain BTL 1 Remembering in detail. 18.7 volt. (16) 8. θ is the usual spherical coordinate and âr is the radial unit vector. BTL 3 Applying Using the expression obtained for directivity determine the maximum directivity of the antenna for an infinitesimal linear dipole of length l<< λ for which the radial component of the power density is . (16) 2. Modify the above BTL 5 Evaluating equation to get the equation for “directivity from aperture”. 17. Describe the structure with diagram and operation principle of Yagi-Uda BTL 1 Remembering array in detail. 13. Explain the impedance matching using Baluns. Devise an appropriate equation to find the intrinsic impedance of a dipole. BTL 6 Creating Part B 1. Analyze the θ and φ patterns in an antenna radiation pattern and mention BTL 4 Analyzing what does dB and dBi denotes. Design a λ\2 dipole antenna to resonate at a frequency of 5GHz. (16) 3. (16) 12. Wav = Wr = Ao (sin2 θ / r2) (W/m2) (16) 10. Justify the statements “Directivity is equal to the number of point sources in the sky that the antenna can resolve” and “Directivity is directly BTL 5 Evaluating proportional to the antenna effective aperture . (16) . The directional BTL 4 Analyzing characteristics of the antenna are represented by the radiation intensity of U = Bo cos3θ(ω /Sr) for 0 < θ ≤ π/2 and 0 < φ ≤ 2π Find the maximum power density at a distance of 1000 m. (16) 14. Analyze the electric and magnetic field components of a finite length BTL 4 Analyzing dipole antenna and show its current distribution with respect to its length in terms of the wavelength. The power radiated by a lossless antenna is 10 Watts. assuming far field distance. (16) 11. Specify the angle where this occur and find the directivity and half power beamwidth of the antenna. (16) 13. Design the field equations for a Hertzian dipole to produce the purely BTL 6 Creating resistive intrinsic impedance. Derive the expression for the field quantities radiated from a λ/2 dipole BTL 4 Analyzing and prove that the radiation resistance to be 73 Ω . Ae ” . How the aperture blockage can be prevented in reflector antenna? BTL 1 Remembering 6. Recall the definition of FNBW and HPBW of aperture antenna. PART A Q. Determine the beam width and directivity of a pyramidal horn with BTL 5 Evaluating aperture dimensions of 12 x 6 cm. Reflector antenna. Compare Parabolic and Corner Reflector Antennas. BTL 5 Evaluating 10. BTL 1 Remembering 13. BTL 4 Analyzing 8. BTL 4 Analyzing 4. BTL 6 Creating 2. BTL 1 Remembering . Classify the different feed structures used for parabolic reflector. Aperture blockage. BTL 4 Analyzing 11. Relate the field equivalence principle with aperture antennas. What are the advantages of Cassegrain feed? BTL 1 Remembering 7. Horn antenna. BTL 2 Understanding 9. UNIT II APERTURE AND SLOT ANTENNAS Radiation from rectangular aperture. Solve the diameter of aperture of a parabolic antenna to produce a BTL 3 Applying null beam width of 10ᵒ at 3GHz. 5. List the merits and applications of offset feed reflector antenna. Draw and explain the different types of horn antennas. BTL 1 Remembering 12. Numeric tool for antenna analysis. Uniform and Tapered aperture.No Questions BT Competence 1. Define aperture blockage. Feeding structures. Name some numerical tools that can be used to analyze an antenna. slot antennas. BTL 1 Remembering 14. Examine the word „antenna tapering‟. 3. applications. Microstrip antennas-Radiation mechanism. Discuss about the features of the pyramidal horn antenna. operating at a frequency of 10 GHz. Make use of the design equations design a microstrip patch antenna BTL 3 Applying at an operating frequency of 6 GHz.5 deg HPBW at a frequency of 8.2 cm and b = 3. (10) . (i) A rectangular aperture with a constant field distribution with BTL 1 Remembering a=4λ and b=3λ. (6) BTL 5 Evaluating (ii)A pyramidal horn antenna having aperture dimensions of a = 5. (10) (ii) A spherical reflector has a 10 feet diameter. Identify the limitations of a microstrip patch antenna. Assume an efficiency constant = 0. (i) Point out the principle of operation of a rectangular horn antenna BTL 4 Analyzing with neat sketch. Describe rectangular apertures and derive expressions for its BTL 1 Remembering uniform distribution on an infinite ground plane and space. (i) Explain in detail about the tapering in antennas. BTL 2 Understanding 18. BTL 2 Understanding 16. (i) Calculate the antenna gain and effective aperture of the reflector BTL 3 Applying antenna that has a 0.2 GHz. (16) 4. BTL 6 Creating PART – B 1.15. BTL 1 Remembering plane and H-plane Sectoral horns. If at 11. is mounted on an infinite ground plane. (6) 3. (i) Explain how a parabolic antenna gives a highly directional BTL 2 Understanding pattern. Find the maximum permissible aperture. Outline the applications of microstrip antenna. (8) (ii) Examine the salient features of Flat and Corner reflector antennas (8) 5. (10) (ii) Write short notes on the beamwidth and directivity of rectangular apertures. Illustrate any four CAD tools & their features for antenna analysis. On what principle slot antenna works? Explain the principle.6. (8) (ii) Interpret the significance of f/D ratio of a parabolic reflector (8) 7. Determine its gain and HPBW.8 cm is used at a frequency of 10GHz. BTL 3 Applying 20. BTL 2 Understanding 17. 19. (16) 2. Find the (a) FNBW and HPBW in E-plane (b) FSLBW and FSLMM in E- plane and (c) Directivity. Elaborate the Huygens principle for Aperture antennas. Enumerate the radiation pattern and fields on the axis of an E. (6) 6.2 GHz the maximum allowable phase error is λ/16. Enumerate the features of the adaptive array and where it is BTL 1 Remembering employed? 5. Write about pattern multiplication and its advantages. Draw the radiation pattern ofan isotropic point sources of same BTL 1 Remembering amplitude and opposite phase that are λ/2 apart along X-axis symmetric with respect to the origin. develop the various methods of feeding a slot antenna. (16) 12. illustrate and explain the different feed BTL 4 Analyzing mechanism used for parabolic reflector antennas. BTL 1 Remembering 4.No Questions BT Competence 1. With necessary sketches. (10) 10. How to eliminate minor lobes? BTL 1 Remembering . Broadside and End fire array – Concept of Phased arrays. Pattern multiplication. (16) 14. (6) (ii) Summarize various feeding techniques for the rectangular patch antenna with neat diagrams. Define array factor. BTL 6 Creating (8) (ii) Formulate the Uniform aperture distribution on an infinite ground plane for a circular aperture. (8) (ii) Draw different techniques used to feed the slot antenna. illustrate the radiation mechanism of a BTL 3 Applying microstrip patch antenna. BTL 4 Analyzing Draw the different types of Horn structures. What are the advantages of cassegrain feed? (16) 11. Explain one of them in detail. What is meant by grating lobe? Mention the significance of side lobe BTL 1 Remembering level. (i) Identify the importance of Babinet‟s principle on BTL 1 Remembering complementary antennas. 6. Evaluate the radiation mechanism of Horn antenna with diagram. 8. Basic principle of antenna Synthesis-Binomial array. With neat sketch. (8) UNIT III ANTENNA ARRAYS N element linear array. 2. Adaptive array. PART A Q. (8) 9. (i) In detail. (i) Outline the numerical techniques useful for the analysis of BTL 2 Understanding antenna. BTL 1 Remembering 3. (16) 13. Illustrate the aperture blockage and explain how it can be BTL 2 Understanding overcome by the offset feed. 20. BTL 2 Understanding 11. Devise the relative excitation levels of a binomial array of 2 and 3 BTL 6 Creating elements. Formulate the directivity of an array. Give an account of beamforming networks for phased array antenna.(8) 4.7. Enumerate the expression for steering vector of phased array antenna BTL 1 Remembering and explain its significance. Identify the feed networks used in a phased array antenna . Compare end fire and broad side array. A linear end fire. (16) 3. BTL 1 Remembering derive the field quantities and draw its radiation pattern for the phase difference of 45o. Summarize the advantages of linear array antenna. Draw the radiation pattern for broad side and end fire array. BTL 4 Analyzing 16. Identify the directivity and beamwidth. BTL 5 Evaluating 18. BTL 3 Applying 14. Show the conditions to obtain end fire array antenna. BTL 4 Analyzing 17. PART – B 1. BTL 2 Understanding 9. Obtain the expression for the field and the radiation pattern produced BTL 1 Remembering by a N element array of infinitesimal with distance of separation λ/ 2 and currents of unequal magnitude and phase shift 180 degree. BTL 2 Understanding 8. BTL 3 Applying 13. (16) 2. Illustrate the meaning and need for the binomial array. uniform array of 10 elements has a separation of λ/4 BTL 6 Creating between elements. BTL 5 Evaluating 19. (i)Quote and derive the expression for field pattern of broad side array of BTL 1 Remembering N point sources. Differentiate Binomial and Chebyshev distributions. (8) (ii)A linear broadside array consists of 4 equal isotropic in-phase point sources with λ/3 spacing. Explore the need for phase shifter in phased array antennas. BTL 2 Understanding 10. (16) . Interpret the meaning of linear array and point source. For a 2 element linear antenna array separated by a distance d = 3 λ/4 . 15. Find the directivity of broadside forms of arrays when a uniform linear BTL 4 Analyzing array contains 50 isotropic radiation with an inter element spacing of λ/2. Classify antenna arrays. BTL 3 Applying 12. Enumerate the basic principle of antenna synthesis. (8) (ii)Describe the radiation mechanisms of binomial array with neat sketches and derive the expression for array factor. (16) 13. (i) Discuss the radiation mechanisms of broad side antenna array and BTL 2 Understanding End fire antenna array with neat sketches. (8) 10. (16) 14. pattern maxima. Discuss and derive the expressions for directivity of the following N BTL 2 Understanding element linear array antennas. Compose the resultant radiation for β=00 and thereby identify the direction of maximum radiation. Summarize and prove mathematically for finding directions of pattern nulls of the array. (8) 12. (8) 11. (16) 6. (i) Broad side array (ii) End fire array (iii) Phased array(iv) Tapered array (16) 8. (8) (ii) Examine how analog and digital beam forming is achieved with an antenna array with a neat diagram. (i) Find the array length . (8) 9. (8) (ii) What is binomial array? Draw the pattern of 10 element binomial array with spacing between the elements of 3λ/4 and λ/2. (i) Show the expression for the field produced by linear array and BTL 3 Applying deduce it for an end fire array. (8) (ii) Express the characteristics of broad side and end fire array. number of elements when elements in an BTL 4 Analyzing array are spaced at λ/2 and null-to-null beamwidth for an array of dipoles of λ/2 length in end fire mode which produces a power gain of 28. (i)Illustrate about the method of pattern multiplication. Deduce an expression for the far field of a continuous array of point BTL 5 Evaluating sources of uniform amplitude and phase. Review how does the directivity of an array represent the figure of BTL 2 Understanding merit on the operation of the system? Derive expressions for the directivity of broadside array and end fire array. (8) 7. (16) . (8) BTL 3 Applying (ii)Solve the expression for directions of pattern minima.5. BWFN due to broad side array. An antenna array consists of two identical isotropic radiators spaced BTL 6 Creating by a distance of d=λ/4 meters and fed with currents of equal magnitude but with a phase difference β. (i)Analyze the working principle of phased array antenna with neat BTL 4 Analyzing diagram. Identify the direction of maximum and minimum radiation from the BTL 4 Analyzing resultant radiation of two identical radiators which are spaced d = 3 λ/4 meters apart and fed with currents of equal magnitude but with 180o phase difference. BTL 1 Remembering 7. Polarization.Reconfigurable antenna. BTL 4 Analyzing 16. 14. Define EBG structures. Summarize the applications of helical antenna. UNIT IV SPECIAL ANTENNAS Principle of frequency independent antennas –Spiral antenna. Dielectric antennas. Modern antennas . PART A Q. Discuss the drawbacks in measurement of antenna parameters. BTL 5 Evaluating . BTL 4 Analyzing 15. Select the requirements and types of anechoic chamber. How active antennas are wide interest for industrial applications? BTL 1 Remembering 5. Identify why antenna measurements are necessary? BTL 3 Applying 13. Infer the applications of log periodic antenna. Show the instruments required to accomplish an antenna BTL 3 Applying measurement task. Active antenna. Give applications of EBG structures in antenna engineering. Explain why frequency independent antennas are called so? BTL 2 Understanding 9. BTL 4 Analyzing 17. Write types of EBG structure. Measurement of Gain. Tell about absolute gain and gain transfer. 12. Radiation pattern. Compare and contrast wedges and pyramids. Antenna Measurements-Test Ranges. BTL 2 Understanding 11. Classify reconfigurable antenna by considering the properties of a BTL 3 Applying base design.No Questions BT Competence 1. Point out the near and far field measurements. Log periodic. Illustrate the difference between planar and conical spiral antenna. Electronic band gap structure and applications. State Rumsey‟s principle. VSWR. What is pitch angle of a helical antenna? BTL 1 Remembering 2. BTL 1 Remembering 3. BTL 2 Understanding 10. BTL 1 Remembering 4. BTL 1 Remembering 6. BTL 2 Understanding 8. Helical antenna. diameter 0. (16) 7. (i) Design a log periodic antenna to obtain a gain of 9dB and to BTL 4 Analyzing operate over a frequency range of 125MHz to 500MHz. On what principle slot antenna works? BTL 6 Creating 20. (8) (ii) Demonstrate the compact antenna test ranges. (8) . (16) 2. number of turns equal to 20 and operates at 1. and analytical BTL 2 Understanding evaluation of dielectric resonator antenna. With neat schematic explain in detail about log periodic antennas. Generalize the antenna test range types. (i) Identify the reciprocal relationship between Tx antenna and Rx BTL 3 Applying antenna.05m. Illustrate the antenna gain measurements by (i)gain comparison BTL 3 Applying method (ii) absolute method with neat diagram. (8) 10.861 and σ=0. (6) 3. BTL 2 Understanding What is the need for feeding from end with shorter dipoles and the need for transposing the lines? Also discuss the effects of decreasing alpha. reconfiguration BTL 2 Understanding mechanism of reconfigurable antenna. (16) 9. feeding methods. near field and far field with neat diagrams. Summarize the initial. (16) 8. practical considerations. (16) BTL 1 Remembering 5. ?=0. What is the importance of helical antenna? Explain the BTL 1 Remembering construction and operation of helical antenna with neat sketch.1m.162. BTL 6 Creating PART – B 1. (10) (ii) Compare defected ground structure and EBG. Interpret the characteristics. Recommend the expressions for design ratio. (8) 4.000 MHz. (i) Write the classification of Electromagnetic Band-Gap (EBG) BTL 1 Remembering structures and explain. (i) Discuss in detail the measurement of Polarization. (16) 11. find the Null-to-Null beam width of the main beam and also half-power beam width and directivity. Explain about anechoic chamber. (8) BTL 1 Remembering (ii) If a helical antenna has a spacing between turns 0. (16) 6. Explain the procedures for the measurement of VSWR. Analyze in detail the normal mode and axial mode operation of the BTL 4 Analyzing helical antenna. Interpret how dipole antenna is reconfigurable by frequency. spacing factor and BTL 5 Evaluating frequency ratio of log periodic antenna? 19.18. BTL 4 Analyzing (16) 13. Maximum usable frequency – Skip distance. Fading . Give the factors that affect the propagation of radio waves. 8. BTL 1 Remembering 7. Discuss the principle of frequency independent behavior of LPDA BTL 6 Creating in detail and explain its construction. Describe in detail the set up for measurement of Radiation pattern. Explain the planar equiangular spiral. Tell about Space diversity Reception. BTL 1 Remembering 2. Show flat earth and curved earth propagation. (8) 12. Tropospheric propagation . (16) UNIT V PROPAGATION OF RADIOWAVE Modes of propagation . What is meant by multihop propagation? BTL 1 Remember 4. Troposcatter propagation .No Questions BT Competence 1. BTL 1 Remembering 6. (16) 14. critical frequency . BTL 1 Remembering 3. (ii) Examine the impact of reciprocity theorem in determination of antenna impedance . BTL 1 Remembering 5. BTL2 Understanding 10. Mention about the free space loss factor. Discuss the effects of ground plane on low frequency BTL 2 Understanding transmission. BTL2 Understanding . Structure of atmosphere . Multi hop propagation PART A Q. Is it possible to transmit horizontal polarized wave as a surface BTL2 Understanding wave? 9. Ground wave propagation . Duct propagation. Archimedean spiral and BTL 5 Evaluating Conical spiral antenna with neat diagram and necessary design equations. Summarize the features of Magneto-Ions Splitting. Define maximum usable frequency in a sky wave propagation. Recall Critical frequency. Flat earth and Curved earth concept Sky wave propagation – Virtual height. Sketch the atmospheric structure. (6) BTL 1 Remembering (ii)Write notes on the wave propagation in complex environments. Explore on Frequency Diversity reception. if the transmitter and receiver are separated by 500km. (i) Tell about sky wave propagation and explain the Effects of BTL 1 Remembering ionosphere abnormalities. (i) Define the terms Skip distance and Virtual height. (12) (ii) Determine the critical angle of propagation for D-Layer.24x106cm-3 19. Illustrate skip distance of sky wave. (8) BTL 2 Understanding (ii) Outline the expression for field strength at the receiving antenna. 14. (i) Review the effect of Earth‟s magnetic field on ground wave BTL 1 Remembering propagation. BTL 6 Creating 20. Find the range of LOS system when receive and transmit BTL 3 Applying antenna heights are 10 m and 100m respectively. BTL 4 Analyzing 16. 18. (6) 4. Analyze the various types of diversity reception. Examine how fading is compensated in multipath propagation. BTL 4 Analyzing 15. (10) (ii) Point out Critical frequency and maximum usable frequency in wave propagation. BTL 6 Creating PART-B 1. BTL 4 Analyzing 17. (i) Summarize the structure of the atmosphere and explain BTL 2 Understanding each layer in detail. Express virtual height and actual height in terms of BTL 5 Evaluating mathematical equations. (10) 2. (6) . Formulate gyro frequency. Find the critical frequency of an ionosphere layer which has an BTL 5 Evaluating electron density of 1. (i)What is the mechanism of space wave propagation over BTL 1 Remembering ideal flat earth with a neat sketch? (8) (ii) How does the earth affect ground wave propagation? (8) 3. BTL 3 Applying 13. (8) 6.11. (i) List out the properties of radio waves. BTL3 Applying 12. (8) (ii)Can you tell the mechanism of ionospheric propagation with neat diagram? (8) 5. Outline the features of duct propagation. 92 at the frequency of 10 MHz. find the range if the frequency is MUF. Calculate the path loss of the link and the received power. (6) BTL 4 Analyzing (ii) Discuss the effects of diffraction on EM Waves. Assume flat earth and negligible effect of earth‟s magnetic field. (16) 14. (i) Analyze about Duct propagation and explain in detail. The distance between the two antennas is 30km and the power radiated by the transmit antenna is 10W. (10) 11. (8) (ii) Derive the expression for the MUF for flat earth and curved earth. i) Construct a 2 ray model of sky wave propagation and BTL 3 Applying explain in detail. Also derive an expression for the effective relative dielectric constant of the ionosphere. (8) (ii) Explain LOS propagation and troposcatter propagation (8) 8. (8) 13. solve and find the distance between these two points on the earth.7. Explain about the models of diffraction. For such a case. BTL 5 Evaluating Discuss its advantages and disadvantages. (i) The receiver and the transmitter are located at the LOS on BTL 3 Applying the earth. (i) Summarize the attenuation characteristics for ground wave BTL 2 Understanding propagation. The height of the ray reflection point on the ionospheric layer is 400km. Draw the electron density profile chart of an ionosphere and BTL 6 Creating explain. (10) (ii) Illustrate the multihop propagation with diagram (6) 9. (i) A free space LOS microwave link operating at 10GHz BTL 4 Analyzing consists of a transmit and a receive antenna each having a gain of 25dB. Explain about reflection and refraction of waves in ionosphere. Explain the tropospheric scatter propagation phenomenon. (8) ii) When the maximum electron density of the ionospheric layer corresponds to refractive index of 0. (i)Examine whistlers and Faraday rotation. (16) . (8) 10. (6) BTL 4 Analyzing (ii) How would you explain surface wave propagation? (10) 12.
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