Since,the short electric dipole is so short,the current which is flowing through the dipole is assumed to be constant throughtout its length.The effect of this current is not felt instantaneous at a distance point only after an interval equal to the time required for the wave to propagate over the distance r is called the retardation time. Explain a. 4. Structure of ionosphere, Refraction and Reflection of Sky Waves by ionosphere, Ray Path, Critical Frequency, MUF, LUF, OF, Virtual Hlght and Skip Distance. iii. Find dipole length and radiated power. iii. The distance with in which a signal of given frequency fails to be reflected back is the skip distance for that frequency.The higher the frequency the greater the skip distance. 33.i) Write a short note on Traveling wave antenna. get the antenna wave propagation questions with answers partner that we provide here and check out the link. Define wave velocity and Group velocity.? Antenna and wave Propagation, AWP Questions For placement and exam preparations, MCQs, Mock tests, Engineering Class handwritten notes, exam notes, previous year questions, PDF free download LectureNotes.in works best with JavaScript, Update your browser or enable Javascript 39. Tower . (Ae). Beam efficiency = SM = WM / WA. All the Multiple Choice Question and Answer (MCQs) have been compiled from the books of Data Communication and Networking by The well known author behrouz A forouzan. 3. (ie 10 Km from Earth surface). Dear Readers, Welcome to Antenna & Wave Propagation multiple choice questions and answers with explanation. ii) Explain the term pattern multiplication. Introducing Textbook Solutions. Antenna is a transition device or a transducer between a guided wave and a free space waveor vice versa. List the arrays used for array tapering . 53.Why a short dipole is also called an elemental dipole? [ ] a) Linear. Derive the expression for Permitivity and conductivity of ionized gas.? The total field pattern of an array of non isotropic but similar sources is the product of the i) individual source pattern and ii) The array pattern of isotropic point sources each located at the phase center of the individual source having the same amplitude and phase. Since radio transmission is Omni directionalin nature, the need to physically align the transmitter and receiver does not arise. It is defined as an antenna is a circuit device with a resistance and temperature on the one hand and the space device on the other with radiation patterns, beam angle ,directivity gain and aperture. The number at the end within the bracket identifies which of the four multiple choice answers is the correct one. d. Parasitic array. Derive the maxima ,null directions and also the beamwidth of a Endfire array. b. ii) For certain applications, it is highly desirable that secondary lobes should be eliminated completely or reduced to minimum desirable level compared to main lobes. D .Kraus Book). Then It is -----array. This is the Multiples Choice Questions Part 1 of the Series in Antennas as one of the Communications Engineering topic. An array is linear when the elements of the array are spaced equally along the straight line. The directivity of an antenna is equal to the ratio of the maximum power density P(q,f)max to its average value over a sphere as observed in the far field of an antenna. b. Faraday rotation in Sky wave Propagation. Wave front is basically a locus of points acquiring similar. Which among the following is an application of high frequency? , M I S T E . 2. In this array the elements are fed parasitically to reduce the problem of feed line. ANTENNAS AND WAVE PROPAGATION 2015 MULTIPLE CHOICE QUESTIONS UNIT-1: ANTENNA BASICS 1. Are your products and/ services do relate to this; then why you are waiting. Interference of normal radiation & radio wave propagation, If the path difference of two waves with single source traveling by different paths to, arrive at the same point, is λ/2, what would be the phase difference between, Which ionization layer exists during day time & usually vanishes at night due to highest, What is the possible range of height for the occurrence of sporadic E-region with, layer of appleton region acts as a significant reflecting medium for, The knowledge of which parameter is sufficient for deriving the time varying, According to Webster’s dictionary, what is an. Electrically Large loop antennas is one in which the overall length of the loop approaches the wavelength. , M I S O I . Visit our Antenna job interview questions and answers page designed by our experts … Electronics and Communication Engineering ECE FAQ Antennas and Wave Propagation Unit wise Two Marks, Short, Viva, Interviews Questions and Answers PDF Write short notes on i) Ground wave propagation ii) space wave propagation. A short dipole is initially in neutral condition and the moment a current starts to flow in one direction,one half of the dipole require an excess of charge and the other a deficit because a current is a flow of electrical charge.Then ,there will be a voltage between the two halves of the dipole.When the current changes its direction this charge unbalance will cause oscillations.Hence an oscillating current will result in an oscillating voltage.Since,in such dipole,electric charge oscillates ,it may be called as Oscilllating electric dipole. Write short note on i) Vector potential ii) modification potential iii) Retarded Potential. 52.How radiations are created from a short Dipole? RADAR SYSTEMS Questions and Answers pdf :-UNIT I :-1. Broad side array. Which of the following waves has the lowest propagation speed? Derive the expression for radiation field and radiation resistance. Gain 3. 54.What is a Infinitesimal Dipole? Similar point sources with equal maximum amplitudes are called identical point sources. It is the addition of above three apertures. This preview shows page 1 - 4 out of 31 pages. wave velocity vp = c / ¥__- (fc / f)2 Group velocity, vp vg = c2 vg = c2 / vp. 43. i. (Ap). iii. Antenna beam width is an angular width in degrees, measured on the radiation pattern (major lobe) between points where the radiated power has fallen to half its maximum value .This is called as “beam width” between half power points or half power beam width.(HPBW). Absorption character of ionosphere for the paths between transmitter and receiver. Which among the following is/are not present in free space? What is meant by identical Point sources.? Electrically Small loop antennas is one in which the overall length of the loop is less than one-tenth of the wavelength. Explain about the frequencies used for radar 5. Dr.V.Thrimurthulu Lecture Notes Antenna & Wave Propagation CREC Dept. 47.What are the advantages of binomial array? \34. 36. The lowest useful HF for a given distance and transmitter power is defined as the lowest frequency that will give satisfactory reception for that distance and power. Due to the earth’ s magnetic fields, the ionosheric medium becomes an isotropic and the incident plane wave entering the ionosphere will split into ordinary and extra ordinary waves/modes. Explain the different types of Diversity technique. 18. Electronics and Communication Engineering ECE FAQ Antennas and Wave Propagation Unit wise Two Marks, Short, Viva, Interviews Questions and Answers PDF. You have remained in right site to begin getting this info. Antenna beamwidth is a measure of directivity of an antenna. ii) With neat sketch explain the operation of Helical antenna. 16. Relation between and Skip Distance, Multi-hop Propagation. Inverse bending may transform line of sight path into an obstructed one. Discuss the design aspects. TASK: Identify the characteristics of wave propagation. Derive the expression for the radiated field from a short dipole. 90. They are Elliptical polarization ,circular polarization and linear polarization. 27. i) State and Prove reciprocity theorem. Directivity from beam area(WA ). Attenuation of this wave is directly affected by the constant of earth along which it travels. It is the area over which the power is extrated from the incident wave and delivered to the load is called effective aperture. 28.What is meant by uniform linear array.? 28. i.e Maximum radiation intensity from test antenna Gain (G) = --------------------------------------------------------, ----------------------- Maximum radiation intensity from the reference antenna with same input power. Following is the list of multiple choice questions in this brand new series: MCQ in Radiation and Wave Propagation . Planning for an excelling and compelling career as an Antenna Engineer? The ratio of maximum radiation intensity in given direction to the maximum radiation intensity from a reference antenna produced in the same direction with same input power. 1 m – 10 m b. TQ, visit us again. Waves that arrive at the receiver after reflection in the ionosphere is called sky wave. In which kind of waveform is the phase velocity defined? Page 5 MULTIPLE CHOICE QUESTIONS UNIT-3: ANTENNA ARRAYS 1. UNIT VIII Wave Propagation – II: Antenna and wave propagation pdf; Sky Wave Propagation — Introduction. Space wave ii. 6.What are the different types of aperture.? 39.What is the need for the Binomial array.? ANTENNA and WAVE PROPAGATION Multiple Choice Questions :: 51. End fire array c. Collinear array. Whenever the variation of the amplitude and the phase of the field with respect to the absolute angle for any two sources are same then they are called similar point sources. 12.Derive the expressions for the fields and power radiated from a half wave dipole antenna.Find its radiation resistance and directivity. As the distance from the current element or the short dipole increases ,both induction and radiation fields emerge and start decreasing .However,a distance reaches from the conductor at which both the induction and radiation field becomes equal and the particular distance depends upon the wavelength.The two fields will thus have equal amplitude at that particular distance. The presence of near by antenna no.2 induces a current in the antenna no.1 indicates that presence of antenna no.2 changes the impedance of the antenna no.1.This effect is called mutual coupling and results in mutual impedance. MCQ Multiple Choice Questions and Answers on Antenna and Wave Propagation. Professionals, Teachers, Students and Kids Trivia Quizzes to … Write the potential function in different form. Find the radiated power of an antenna if 10 Amp current exists and its radiation resistance 32 ohm. 38. Medium Frequency Polarization Power 2. Thus WA = WM+ Wm . Derive basic radar’s equation 4. Tapering is done from center to end. 40. It states that the vector product of electric field intensity vector E and the magnetic filed intensity vector H at any point is a measure of the rate of energy flow per unit area at that point.The direction of power flow is perpendicular to both the electric field and magnetic field components. 75.Which antenna will produce circularly polarized waves Helical antenna radiates circularly polarized wave. b) Non-Linear. When the length of the short dipole is vanishingly small,then such a dipole is called a infinitesimal dipole.If dl be the infinitesimally small length and I be the current,then Idl is called as the current element. It is made up of direct wave and ground reflected wave. 92. B. 1 cm – 10 cm c. 10 cm – 1 m d. 0.1 cm – An antenna is an electrical conductor or system of conductors. PDF | On Apr 2, 2013, mahendra Kumar published multiple choice questions on wireless communication | Find, read and cite all the research you need on ResearchGate 70.What are Electrically Small loop antennas? R A V E E N D R A M . Derive the radiation field and radiation resistance from a half wave dipole. At low frequencies, the waves can pass through obstacles easily. For a charge moving with uniform velocity with straight & infinite wire, ANSWER: For a charge oscillating in time motion. Radiation pattern is the relative distribution of radiated power as a function of distance in space .It is a graph which shows the variation in actual field strength of the EM wave at all points which are at equal distance from the antenna. This means that if a sinusoidal voltage is input at the antenna terminals with amplitude 1 Volt, the current will have an amplitude of 1/50 = 0.02 Amps. 7. Multiple Choice Questions and Answers on Antenna & Wave Propagation 1) What is the wavelength of Super high frequency (SHF) especially used in Radar & satellite communication? * Ask us, what you want? Physical aperture. MCQ quiz on Antenna and Wave Propagation multiple choice questions and answers on antenna and wave propagation MCQ questions quiz on antenna and wave propagation objectives questions with answer test pdf. Directivity from Pattern. Define dipole antenna. Multi path fading is caused by interference between the direct and ground reflected waves as well as interference between two are more paths in the atmosphere. The effective height h of an antenna is the parameter related to the aperture.It may be defined as the ratio of the induced voltage to the incident field.i.e H= V / E. The fields around an antenna may be divided into two principal regions. Omnidirectional antenna. Space diversity reception. The exam of 100 Questions will be drawn from the Basic question bank (RIC-7). iv) collecting aperture. c) Both a and b. What is the principle of the pattern multiplication? i. 9.Explain the principle of pattern multiplication with some examples. i. Curvature of earth. It is an array in which the amplitudes of the antenna elements in the array are arranged according to the coefficients of the binomial series. i.e FBR = Power radiated in desired direction / power radiated in the opposite direction. Eg. Derive the maxima ,null directions and also the beamwidth of a broadside array. Graphical representation of the radial component of the pointing vector Sr at a constant radius as a function of angle is called power density pattern or power pattern. 24. Subscribe via Email, to get the latest articles [updates] from this site. It is the waves originate at a fictitious volumeless emitter source at the center ‘O’ of the observation circle. The applications of helical antenna are: . tenth wave length maximum specified for a short dipole.Elemental dipole is also called as elementary dipole,elementary doublet and hertzian dipole. It is used in normally in microwave links, and it is found that signal transmitted over the same path in two polarizations have independent fading patterns.in broad band dish antenna system, Polarization diversity combined with frequency diversity reception achieve excellent results. Specially developed for the Electronic Engineering … Give it a try and share your score. iii) Loss aperture. The required field strength which in turn depends upon the radio noise at the receiving location and type of service involved . Impedance 4. Wave that is guided along the earth’ s surface like an EM wave is guided by a transmission is called surface wave. An antenna is a system of similar antennas oriented similarly to get greater directivity in a desired direction. Finally the plane of polarization will usually have changed, this phenomenon is known as Faraday’ s rotation. _It is on many othe probes of planets and comets,including moon and mars,being used alone,in arrays or as feeds for parabolic reflectors,its circular polarization and high gain and simplicity making it effective for space application. 5.Define Polarization? 88 .Define frequency diversity Reception. The efficiency of an antenna is defined as the ratio of power radiated to the total input power supplied to the antenna. Ans:The dipole has two equal charges of opposite sign oscillating up and down in a harmonic motion.The charges will move towards each other and electric filed lines were created.When the charges meet at the midpoint, the field lines cut each other and new field are created.This process is spontaneous and so more fields are created around the antenna.This is how radiations are obtained from a short dipole. 29.i)What is folded dipole antenna ? Yagi uda antenna. a. SONAR b. Subsurface communication c. Radio navigation d. Facsimile ANSWER: Facsimile 3) Wavefront is basically a locus … Course Hero is not sponsored or endorsed by any college or university. WA = ò ò4p Pn ( q,f ) dW ,Where dW = Sin q d q .df. A pinoybix mcq, quiz and reviewers. 32. Page 2/9. wave propagation, including ground wave and ionospheric propagation, goes on to make this text a useful and self-contained reference on antennas and radio wave propagation. Bandwidth 2. It is defined as the ratio of the power radiated in desired direction to the power radiated in the opposite direction. In uniform linear array as the array length is increased to increase the directivity, the secondary lobes also occurs. Surface wave. What is meant by front to back ratio.? 91. i.e Aperture efficiency = hap = Ae / Ap (dimensionless). Antenna and Wave Propagation Question and Answer Explain the different types of polarization in detail. Wave propagation is any of the ways in which waves travel. 25. 23. iv. Tags. If the elements are fed with currents of equal magnitude and having a uniform progressive phase shift along the line, then it is called uniform linear array . Give it a try and share your score. Visit Wisdom jobs to look into the various Antenna jobs available along with the training and assessment material for improving your knowledge base and sample resumes for a winning job and Antenna interview questions. (See Figure from John. figures / diagrams, tables / values, answers / explanations and more. * To get Clear; figures / diagrams, tables / values, answers / explanations and more, download the Antennas and Wave Propagation Viva Short Questions and Answers PDF. Waves propagated over other paths near the earth surface is called ground wave propagation. This aperture is a measure of the physical size of the antenna. It is the ratio of the reradiated power to the power density of the incident wave. 56.What do you understand by retarded current? 55.Why a short dipole is called a oscillating dipole? End fire array is defined as an arrangement in which the principal direction of radiation is coincides with the array axis. This method takes advantage of the fact that signals of slightly different frequencies do not fade synchronously. 20. 41. • E and H oscillate in phase and ratio of their amplitudes is constant and is equal to: Define gyro frequency. iii. W’ = I2 R Rr = W’/ I2 Where Rr is a fictitious resistance called called as radiation resistance. It is also called as isotropic source or omni directional radiator or simply unipole. Axial mode of operation. Computer Networks MCQ Questions and Answers with PDF Download is offered here so that you can prepare your exams better and score good marks for this chapter. 89. AWP QUES1.pdf - Multiple Choice Questions and Answers on Antenna Wave Propagation 1 What is the wavelength of Super high frequency(SHF especially used, Multiple Choice Questions and Answers on Antenna & Wave Propagation, What is the wavelength of Super high frequency (SHF) especially used in Radar &. A half wave antenna is the fundamental radio antenna of metal rod or tubing or thin wire which has a physical length of half wavelength in free space at the frequency of operation, 65.What is the radiation resistance of a half wave dipole, The radiation resistance of a half wave dipole is given by Rr=73 ohm, A loop antenna is a radiating coil of any convenient cross-section of one or more turns carrying radio frequency current.it may assume any shape (e.g. 22. The ratio of the major to the minor axes of the polarization ellipse is called the Axial Ratio. Eg. 73.What are the parameters to be considered for the design of an helical antenna? 30. Antenna Wave Propagation Questions With Answers related files: 87244389a5b844c4a277fb9944d1a6da Powered by TCPDF (www.tcpdf.org) 1 / 1 _It became thw workhouse of space communications for telephone,television and data,being employed both on satellites and at ground stations. Variation of signal strength occur on line of sight paths as a result of the atmospheric conditions and it is called .It can not be predicted properly. . a. 1. Also includes the portion of energy received as a result of diffraction around the earth surface and the reflection from the upper atmosphere. Wave propagation is any of the ways in which waves travel. These objective type Antenna & Wave Propagation questions are very important for campus placement test, semester exams, job interviews and competitive exams like GATE, IES, PSU, NET/SET/JRF, UPSC and diploma. The power radiated from an antenna per unit solid angle is called the radiation intensity U (watts per steradian or per square degree). The book begins with an introduction that discusses the fundamental concepts, notations, representation and principles that govern the field of antennas. What is meant by Faraday’ s rotation.? 100. Derive the expression for calculating field strength at a distance in space wave Propagation. ii) Write a short note on Self and mutual impedance of antenna. Antennas and Wave Propagation is written for the first course on the same. 26. The frequency of the radio wave determines many of the characteristics of the transmission. Lecture 4 - Practical Machine Learning 1.pptx, Malaviya National Institute of Technology, Jaipur, ECE-VI-ANTENNAS AND PROPAGATION [10EC64]-NOTES, MCQ in Electronics - Wave Propagation And Antenna, Malaviya National Institute of Technology, Jaipur • CSE 306, Visvesvaraya Technological University • ELECTRICAL NA, Sri Sivani College of Engineering • CSE 509, University of Pangasinan • ECE 111005619. The radiation intensity is independent of distance. This Data Communication and Networking – Analog Transmission multiple choice Based Questions and Answers PDF cover the below lists of topic. D = P(q,f)max / P(q,f)av. A isotropic radiator is a fictitious radiator and is defined as a radiator which radiates fields uniformly in all directions. EM wave Acoustic wave TEM wave TE 10 wave 3. 59.At what distance from the dipole is the induction field equal to the radiation field? Explain in detail ionospheric propagation. Far field zone (Fraunhofer zone). ._Many satellites including weather satellites,data relay satellites all have helical antennas . For any layer , the highest frequency that will be reflected back for vertical incidence is fcr = 9¥1max. What is inverse and multi path fading.? Derive the expression for Permitivity and conductivity of ionized gas. (Ae). Axial Ratio, 74.What are the types of radiation modes of operation for an helical antenna The two types of radiation modes of operation possible for an helical antenna are: 1. It is defined the angle between the first nulls (or) it is defined as twice the angle between the first null and the major lobe maximum direction. 16. EmoticonEmoticon. In this array the antenna elements are arranged coaxially by mounting the elements end to end in straight line or stacking them one over the other with radiation pattern circular symmetry. Scattering aperture(As.) Waves that arrive at the receiver after reflection from the troposphere region is called Tropospheric wave. The maximum amplitudes of the individual sources may be unequal. If an e.m.f is applied to the terminals of an antenna no.1 and the current measured at the terminals of the another antenna no.2, then an equal current both in amplitude and phase will be obtained at the terminal of the antenna no.1 if the same emf is applied to the terminals of antenna no.2. STANDARDS: Demonstrate competency of the task skills and knowledge by correctly responding to 70 percent of the multiple choice test covering identification of the characteristics of wave propagation. A short dipole that does have a uniform current will be known as the elemental dipole.Such a dipole will generally be considerably shorter than the. 10.Explain the different techniques used for tapering of arrays. Multiple Choice Questions ∇ × ∇ × E is ∇ ∇ .E −∇2 E ∇2 E − ∇ ∇ .E ∇2 .E + … - Selection from Antennas and Wave Propagation [Book] It is defined as the fictitious resistance which when inserted in series with the antenna will consume the same amount of power as it is actually radiated.The antenna appears to the transmission line as a resistive component and this is known as the radiation resistance. View awp-bitbank-pdf.docx from CSE 304 at National Institute of Technology, Warangal. 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