b. c. Sensor Which angle of rhombic antenna represents one half of included angle of two legs of one wire? This antenna is a monopole in that it uses a half-wavelength radiator, but is fed at a voltage node rather than current node. 44)   Which type of wire antennas are also known as dipoles? 6.53 dB c. Defraction What is the effective radiated power? Pinoybix.org is an engineering education website maintained and designed toward helping engineering students achieved their ultimate goal to become a full-pledged engineers very soon. - Published on 01 Oct 15 a. Generally, it has two opposite acute angles. d. None of the above. In order to increase the gain of Yagi-Uda arrays, what element are added? c. Both a & b b. Resistive a. Curvature of earth c. Propagation constant b. Lorentz c. β + (λ/2) C. Resistivity d. All of the above. d. Tilt angle. d. 0.99 m2, 54)   Dipole antenna is symmetrical in nature where the two ends are at equal potentials with respect to _____point, a. 41)   According to Snell’s law in optics, if a ray travels from dense media to rarer media, what would be its direction w.r.t the normal? a. Tilt angle b. Outward a. b. Spherical to plane wave d. None of the above. 0.0149 m2 A a. If the antenna is not in the exact dimension/measurement, the impedance of the antenna turns to be: 159. 1)   What is the wavelength of Super high frequency (SHF) especially used in Radar & satellite communication? 53)   If a half-wave dipole operates at 300 MHz with λ = 0.5m & D0 = 1.643, what will be its effective area? Also provides professionals with materials for their lectures and practice exams. 193. 35)   Which equations are regarded as wave equations in frequency domain for lossless media? a. Ions 65)   Which angle of rhombic antenna represents one half of included angle of two legs of one wire? b. Ey b. Divergent Antenna array having one active dipole element and two or more parasitic element is known as _______. 179. we respect your privacy and take protecting it seriously, Series of Multiple Choice Questions in Electronics Systems and Technologies, Pinoybix Elex is officially on Google Play | First of …, Complete List of Reviewers to Pass Engineering Board Exam, MCQ in Power Plant Engineering Part 6 | ME Board …, MCQ in Power Plant Engineering Part 5 | ME Board …, MCQ in Power Plant Engineering Part 4 | ME Board …, MCQ in Resonant and Non-resonant Antennas, MCQ in Bandwidth, Beamwidth and Polarization, MCQ in Grounding Systems and Matching Systems, MCQ in Directional and Non-directional Antennas, MCQ in Wideband and Special Purpose Antennas. Help me go forward with the same spirit. 39)   After which phenomenon/phenomena do the waves arrive at the receiving antenna in ionospheric propagation? 190. Only Refraction Front-to-back ratio is the ratio of the forward power and the ________. A closed circuit antenna is also called __________. Perfectly aligned b. If the maximum electron density a. c. Radio navigation Moderate Antenna is also said to be an impedance transforming device. 76)   If the maximum electron density for F-layer in ionosphere is 4 x 106 electrons/cm3, then what will be the critical frequency of EM wave for F-layer? A parabolic dish antenna has a diameter of 3m and operates at 46 Hz. It is known as a single directive antenna. Series 7.99 dB C. Decrease in Magnetic field intensity a. a. This is the Multiples Choice Questions Part 4 of the Series in Antennas as one of the Communications Engineering topic. Reflection or Scattering 187. c. Array 1.047 x 106 m/s Area b. current of about 300A across the radiation resistance 2 Ω. 195. 181. The major lobes of the directive pattern are those in which the radiation is _______. a. Perpendicular For a charge with no motion d. 9.02 dB. ________ is elective means to generate circular polarization. d. Voltage. 80)   What is the functioning role of an antenna in receiving mode? m absorbing area, what is the power received? a. Widest b. Ionized particles c. Both a and b a. 168. d. All of the above. A. MCQ in Antennas from the book Electronic Communication Systems by George Kennedy. c. Inversion layer Point angle a. a. c. Complex fields The presence of dielectric other than air ________ the velocity of light. d. Congruent. d. Invasion layer. B. Eventual Space wave 59)   What is the far-field position of an electric short dipole? Phase Rhombic antenna generally operates on high frequency and very high-frequency ranges. Its polarisation and radiation properties depend on the diameter, pitch, number of turns, wavelength, excitation and spacing between the helical loops. 27.77 ohm d. All of the above. b. c. Diagonal b. b. 196. The case where the electric field lies in a plane parallel to the earth surface. d. Far-field. b. 171. Which among the following is not a disadvantage of rhombic antenna? An antenna is formed of four array antenna, each of which has a gain of _____ if the total gain of these antenna arrays is 30 dB. The variation of the slot antenna is _________. c. Amplitude c. Resistive D. By double side band system. The 32)   If the tower antenna is not grounded, which method of excitation is/are applicable for it? Field pattern estimation due to any length of antenna b. c. Along z-axis A pinoybix mcq, quiz and reviewers. b. Capacitive d. None of the above, ANSWER: Wave is incident normal to plane of the loop with no induced voltage. Calculate effective absorbing area operating at 106 Hz for a standard half-wave dipole. Frequency 1.257 x 106 m/s c. Triangular c. Fraunhofer region c. Helmholtz a. 61)   If a linear uniform array consists of 9 isotropic elements separated by λ/4, what would be the directivity of a broadside array in dB? b. d. None of the above, 20)   In flared transmission line, the radiation phenomenon increases due to ________ in flaring, a. c. 8.55 dB c. Interference of normal radiation & radio wave propagation Normal E-region 71)   When an electromagnetic wave travels from transmitter to receiver, which factor/s affect/s the propagation level? b. b. a. c. Capacitive a. Which antenna is a properly terminated A Marconi B Rhombic C Dipole D Yagi Uda from TRANSMA ECE151 at National University Manila Plane to spherical wave 84)   Under which conditions of two unit vectors, the polarization loss factor (PLF) is equal to unity? 50)   The vector magnetic potential shows the inverse relationship with its ____, a. c. Magnetic field of earth MCQ in Antennas Part 1 as part of the Communications Engineering (EST) Board Exam. b. Dough-nut Is used to increase the current at the base of the antenna, and also to make the current distribution more uniform. d. None of the above. 185. b. Radiated inoyBIX educates thousands of reviewers and students a day in preparation for their board examinations. Normal d. Solid angle. d. All of the above, 48)   Sterdian is a measurement unit of __________, a. b. A wire several wavelengths in length that is suspended at some height above the earth. 172. 13)   Under which conditions of charge does the radiation occur through wire antenna? 62)   If the elements of a binomial array are separated by λ/4, how many shape patterns are generated with no minor lobes? 25)   According to the directivity of a small loop, which value of ‘θ’ contributes to achieve the maximum value of radiation intensity (Umax)? 165. D. Reflectivity. b. Converter Magnetic field intensity 67)   Why are beverage antennas not used as transmitting antenna? c. Both a and b For low and medium frequency antennas which are mounted vertically from the earth’s surface, the effective length is referred to as __________. c. Both a and b a. Aperture a. c. Tropospheric d. None of the above. Which angle of rhombic antenna represents one half of included angle of two legs of one wire? 21)   Which pattern is generated due to plotting of square of amplitude of an electric field? d. None of the above, 24)   From the radiation point of view, small loops are _________radiators. The main difference between half-wave and folded dipole is the __________. In a TV receiver, the linearity can be checked by: (A) VTVM (B) Multimeter (C) Vector gram (D) Pattern generator 9. An area of radiation which exist between adjacent nulls. Narrowest d. Hyperbolic. A pinoybix mcq, quiz and reviewers. Rhombic antenna is a highly directional broad-band antenna with the greatest radiated or received power along the main axis or longer diagonal. a. Apex angle 20 km – 50 km a. d. Front to back ratio (FBR), 17)   If an observation point is closely located to the source, then the field is termed as ________, a. a. Spherical b. Inductor A. Permittivity b. b. Vertical b. b. Imaginary fields 88)   The concept of magnetic vector potential finds its major application in deriving expression of magnetic field intensity especially for ______, a. a. Radiator For a charge moving with uniform velocity with straight & infinite wire c. 0.65 m2 d. Opposite. 191. a. Phase ______ of the antenna is the ratio of the radiation resistance to the total resistance of the system. d. Phase. If the antenna is receiving of 10^-12 v/m of electric field, magnetic field of 3.2 x 10^-3 A/m at a 5 sq. b. c. Elliptical d. None of the above. 164. c. Equality of effective lengths Tilt angle C. Both a and b D. None of the above Ans: Tilt angle 66. b. Mor-gain_antenna_broch_1977.pdf Mor-gain_antenna_broch_1978.pdf Mosley_Antenna_maintenance_2011.pdf Mosley_Checking_traps_2011.pdf Mosley_Devant_special_user.pdf Mosley_El_Toro_review_1965.pdf Mosley_MCQ 182. d. None of the above. 83)   If an antenna draws 12 A current and radiates 4 kW, then what will be its radiation resistance? Radiation from an antenna at other angles than the desired direction. b. a. Inward 1 m – 10 m Power factor of impedance a. Horizontal a. D. Kirchoff’s law. c. Current density Q51 FOR TRANSMISSION LINE LOAD MATCHING OVER A RANGE OF FREQUENCIES ,IT IS BEST TO USE A (A)balun (b)broadband directional coupler (c)double stab (d)single stub of adjustable position ans-c Q52 THE MAIN DISADVANTAGE OF THE TWO HOLE DIRECTIONAL COUPLER IS (A)low directional coupling (b)poor directivity (c)high swr (d) narrow bw ans-d Q53 TO COUPLE A COAXIAL … Side lobe 45)   Which antennas are renowned as patch antennas especially adopted for space craft applications? c. Partial reflection & refraction Electronics and Communication Engineering Questions and Answers. Motion of electrons Start studying MCQ(Antennas). Must be horizontally polarized 4. b. Elliptical a. At the moment, Pinoybix has become one of the most trusted engineering review sites helping thousands of aspiring engineers achieve their goals. a. b. b. Directivity higher than that obtained with uniform phase. The 70.7% point on the polar graph is known as the _________ point and represent the point of maximum width of the lobe. 5)   Which among the following is/are not present in free space? 46)   Which conversion mechanism is performed by parabolic reflector antenna? 49)   According to the geometry, how many sterdians are present in a full sphere? Basically a TV signal from the antenna is processed by: (A) Transmission line (B) RF 37)   In an electrical circuit,which nature of impedance causes the current & voltages in phase? 153. c. Wave is incident in opposite direction of plane of the loop with minimum voltage b. 96)   A rectangular horn antenna operating at 4GHz has the wavelength of 0.075m and gain of about 13dBi. 152. a. 60) Consider the following statements about Rhombic antenna 1. Region c. Reflective region d. All of the above 1 m d. cm. | 6 mounted 8 ) which waveform plays a crucial role in of... Antennas have a quite large structure thus is used in applications where the placement of the above microwave power a! Resonant 2.It is a radiator whose impedance can be directly matched to what of... Of included angle of rhombic antenna generally operates on high frequency and very high-frequency ranges is a in... More about me, please visit my `` about '' Page concentrates its transmitted power! Antenna radiating region/s has/have independent nature of impedance causes the current distribution over the earth surface a! 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