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# MCQ in Antennas Part 4 | ECE Board Exam

This is the Multiples Choice Questions Part 4 of the Series in Antennas as one of the Communications Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies, Communications Books, Journals and other Communications References.

#### Online Questions and Answers Topic Outline

• MCQ in Basic considerations
• MCQ in Wire Radiators in Space
• MCQ in Isotropic Radiator
• MCQ in Current and Voltage Distributions
• MCQ in Resonant and Non-resonant Antennas
• MCQ in Antenna Terms and Definition
• MCQ in Antenna Gain and Resistance
• MCQ in Bandwidth, Beamwidth and Polarization
• MCQ in Grounded and Ungrounded Antennas
• MCQ in Grounding Systems and Matching Systems
• MCQ in Antenna Types
• MCQ in Directional and Non-directional Antennas
• MCQ in Microwave Antennas
• MCQ in Wideband and Special Purpose Antennas

#### Continue Practice Exam Test Questions Part 4 of the Series

151. A discone antenna is a radiator whose impedance can be directly matched to what type of coaxial transmission line?

a. 70 ohm line

b. 30 ohm line

c. 300 ohm line

d. 50 ohm line

View Answer:

Answer: Option D

Solution:

152. In order to increase the gain of Yagi-Uda arrays, what element are added?

a. Using many director

b. Using many dipole

c. Using many reflector

d. All of these

View Answer:

Answer: Option A

Solution:

153. It is a measure of how much the antenna concentrates its transmitted microwave power in a given direction

a. Beamwidth

b. Polarization

c. Bandwidth

d. Gain

View Answer:

Answer: Option D

Solution:

154. The angle where the transmitted power has dropped by from the maximum power in the direction at which the antenna is pointing.

a. Bandwidth

b. Polarization

c. Beamwidth

d. None of these

View Answer:

Answer: Option C

Solution:

155. Orientation of the electric field signal propagated from the antenna.

a. Directivity

b. Polarization

c. Sidelobes

d. Gain

View Answer:

Answer: Option B

Solution:

156. Is not included in the group.

a. Slot

b. Horn

c. Helix

d. Marconi

View Answer:

Answer: Option D

Solution:

157. Radiation from an antenna at other angles than the desired direction.

a. Antenna direction

b. Field strength

c. Sidelobe

d. Directivity

View Answer:

Answer: Option C

Solution:

158. If the antenna is not in the exact dimension/measurement, the impedance of the antenna turns to be:

a. Capacitive

b. Resistive

c. Inductive

d. a or c

View Answer:

Answer: Option D

Solution:

159. Impedance for free space is _______.

a. 120(pi)

b. 30(pi)

c. 180(pi)

d. None of these

View Answer:

Answer: Option A

Solution:

160. 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.

a. 12 dB

b. 13 dB

c. 14 dB

d. 15 dB

View Answer:

Answer: Option C

Solution:

161. ______ of the antenna is the ratio of the radiation resistance to the total resistance of the system.

a. Gain

b. Directivity

c. Efficiency

d. None of these

View Answer:

Answer: Option C

Solution:

162. The major lobes of the directive pattern are those in which the radiation is _______.

a. Minimum

b. Maximum

c. Same

d. None of these

View Answer:

Answer: Option B

Solution:

163. Is one supplied power from the transmitter, usually through a transmission line.

a. Parasitic element

b. Driven element

c. Director element

d. Reflector element

View Answer:

Answer: Option B

Solution:

164. Is one which the principal direction of the radiation is perpendicular to the axis of array.

a. Broadside array

b. End-fire array

c. Phased array

d. Array antenna

View Answer:

Answer: Option A

Solution:

165. Front-to-back ratio is the ratio of the forward power and the ________.

a. Maximum power

b. Optimum power

c. Minimum power

d. Backward power

View Answer:

Answer: Option D

Solution:

166. ________ is elective means to generate circular polarization.

a. Folded antenna

b. Marconi antenna

c. Helix antenna

d. Any antenna

View Answer:

Answer: Option C

Solution:

167. Ranges of frequencies the antenna will radiate effectively.

a. Beamwidth

b. Bandwidth

c. Gain

d. Directivity

View Answer:

Answer: Option B

Solution:

168. Is used to increase the current at the base of the antenna, and also to make the current distribution more uniform.

a. Amplifier

b. Top loading

c. Booster

d. None of these

View Answer:

Answer: Option B

Solution:

169. _________ is a network composed of reactances and transformers, which provide impedance matching.

a. Circulator

b. Antenna coupler

c. Matching section

d. None of these

View Answer:

Answer: Option B

Solution:

170. Consisting of grouped radiations or elements.

a. Turnstile antenna

b. Antenna array

c. Phase array

d. Half-wave dipole

View Answer:

Answer: Option B

Solution:

171. The design ratio of the log-periodic antenna must be _____.

a. Equal to zero

b. Greater than 1

c. Less than 1

d. Unity

View Answer:

Answer: Option C

Solution:

172. For low and medium frequency antennas which are mounted vertically from the earthโs surface, the effective length is referred to as __________.

a. Actual length

b. Effective height

c. Actual height

d. None of these

View Answer:

Answer: Option B

Solution:

173. The main difference between half-wave and folded dipole is the __________.

a. Length

b. Radiation resistance

c. Transmission line

d. None of these

View Answer:

Answer: Option B

Solution:

174. A wire several wavelengths in length that is suspended at some height above the earth.

a. Wire antennas

b. Long wire antennas

c. Short wire antennas

d. Rhombic antennas

View Answer:

Answer: Option B

Solution:

175. Consist of two half-wave dipoles placed at right angles to each other and fed 90o out of phase with each other.

a. Long wire antennas

b. Turnstile antennas

c. Vertical antennas

d. Rhombic antennas

View Answer:

Answer: Option B

Solution:

176. Directivity higher than that obtained with uniform phase.

a. Super gain

b. High gain

c. Medium gain

d. Low gain

View Answer:

Answer: Option A

Solution:

177. A parabolic dish antenna has a diameter of 3m and operates at 46 Hz. Calculate the aperture.

a. 3.5 square meters

b. 4.59 square meters

c. 2.7 square meters

d. 1.2 square meters

View Answer:

Answer: Option B

Solution:

178. If the radiation resistance is 36 ohms, what must be the antenna length?

a. Half-wavelength long

b. One wavelength long

c. Quarter-wavelength long

d. Any of these

View Answer:

Answer: Option C

Solution:

179. 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. m absorbing area, what is the power received?

a. 0.2561 pW

b. 0.72 pW

c. 0.016 pW

d. 0.0012 pW

View Answer:

Answer: Option C

Solution:

180. The case where the electric field lies in a plane parallel to the earth surface.

a. Vertical polarization

b. Horizontal polarization

c. Circular polarization

d. None o f these

View Answer:

Answer: Option B

Solution:

181. It is known as a single directive antenna.

a. Corner director

b. Corner dipole

c. Corner reflector

d. Yagi antenna

View Answer:

Answer: Option C

Solution:

182. The presence of dielectric other than air ________ the velocity of light.

a. Increase

b. Decrease

c. Same

d. Secret

View Answer:

Answer: Option B

Solution:

183. The fact that the second wire of the folded dipole is folded makes the current on the two conductors of the antenna flow in the _______ direction.

a. Same

b. Opposite

c. No

d. None of these

View Answer:

Answer: Option A

Solution:

184. A closed circuit antenna is also called __________.

a. Helix antenna

b. Discone antenna

c. Loop antenna

d. None of these

View Answer:

Answer: Option C

Solution:

185. The omega match is slightly modified from the ___________.

a. T match

b. Gamma match

c. Delta match

d. None of these

View Answer:

Answer: Option B

Solution:

186. A dish antenna has a diameter of 2m and operates at 46 Hz, find the antenna gain at 65% efficiency.

a. 3422.6

b. 3.26 dB

c. 12.3 dB

d. 4266.67

View Answer:

Answer: Option D

Solution:

187. What is the approximate effective length of an antenna at 10 MHz

a. 2.65 m

b. 9.55 m

c. 4.62 m

d. 8.6 m

View Answer:

Answer: Option B

Solution:

188. Calculate effective absorbing area operating at 106 Hz for a standard half-wave dipole.

a. 0.265 mm^2

b. 0.1175 mm^2

c. 1.26 mm^2

d. 2.3 mm^2

View Answer:

Answer: Option B

Solution:

189. The variation of the slot antenna is _________.

a. Isotropic antenna

b. Notch antenna

c. Lenz antenna

d. Horn antenna

View Answer:

Answer: Option B

Solution:

190. A point where the power field strength is zero.

a. Minimum

b. Maximum

c. Lobe

d. Null

View Answer:

Answer: Option D

Solution:

191. An area of radiation which exist between adjacent nulls.

a. Minimum

b. Maximum

c. Lobe

d. Nulls

View Answer:

Answer: Option C

Solution:

192. The property of an antenna that causes it to receive signal better from one direction than from another.

a. Gain

b. Directivity

c. Dipole

d. Reflector

View Answer:

Answer: Option B

Solution:

193. The 70.7% point on the polar graph is known as the _________ point and represent the point of maximum width of the lobe

a. Full power

b. Half-power

c. Quarter point

d. Maximum point

View Answer:

Answer: Option B

Solution:

194. A transmitting antenna has a gain of 10 and a power input of 60 watts. What is the effective radiated power?

a. 6 kW

b. 60 kW

c. 0.6 kW

d. 600 kW

View Answer:

Answer: Option A

Solution:

195. Marconi antenna is used in many types of mobile communications unit because it allows transmission and receptions in _________.

a. One direction

b. Two direction

c. More direction

d. All direction

View Answer:

Answer: Option D

Solution:

196. Used only to a small degree in the VHF band because of its large size requirements

a. Vee antenna

b. Long antenna

c. Rhombic antenna

d. Marconi antenna

View Answer:

Answer: Option A

Solution:

197. A resistance which accounts for the energy dissipated in the form of heat

a. Ohmic resistance

b. Surge resistance

c. Radiation resistance

d. None of these

View Answer:

Answer: Option A

Solution:

198. Antenna array having one active dipole element and two or more parasitic element is known as _______.

a. Marconi

b. Horizontal antenna

c. Ground antenna

d. Yagi-Uda antenna

View Answer:

Answer: Option D

Solution:

199. This antenna is a monopole in that it uses a half-wavelength radiator, but is fed at a voltage node rather than current node.

a. Voltage antenna

b. Zepp antenna

c. Quartz antenna

d. Xylene antenna

View Answer:

Answer: Option B

Solution:

200. Vertical antenna like those used in the AM broadcast and lower frequency armature band rely heavily upon a good __________ for maximum coverage.

a. Insulation

b. Ground system

c. Gain

d. Directivity

View Answer:

Answer: Option B

Solution:

#### Questions and Answers in Antennas Series

Following is the list of multiple choice questions in this brand new series:

MCQ in Antennas
PART 1: MCQ from Number 1 โ 50                        Answer key: PART 1
PART 2: MCQ from Number 51 โ 100                   Answer key: PART 2
PART 3: MCQ from Number 101 โ 150                 Answer key: PART 3
PART 4: MCQ from Number 151 โ 200                 Answer key: PART 4
PART 5: MCQ from Number 201 โ 250                 Answer key: PART 5
PART 6: MCQ from Number 251 โ 300                 Answer key: PART 6
PART 7: MCQ from Number 301 โ 350                 Answer key: PART 7
PART 8: MCQ from Number 351 โ 400                 Answer key: PART 8
PART 9: MCQ from Number 401 โ 450                 Answer key: PART 9
PART 10: MCQ from Number 451 โ 500                 Answer key: PART 10

### Complete List of MCQ in Communications Engineering per topic

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