MCQ in Antennas Part 8 | ECE Board Exam

(Last Updated On: April 4, 2020)

MCQ in Antennas Part 8 | ECE Board Exam

This is the Multiples Choice Questions Part 8 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 8 of the Series

351. Which beam width represents the best antenna directivity?

a. 7 degrees

b. 12 degrees

c. 19 degrees

d. 28 degrees

View Answer:

Answer: Option A

Solution:

352. It is the ratio of the highest to the lowest frequency over which an antenna will satisfactorily operate.

a. channel ratio

b. bandwidth ratio

c. reflection ratio

d. dynamic range

View Answer:

Answer: Option B

Solution:

353. An antenna has a power gain off 15. The power applied to the antenna is 32 W. The effective radiated power is ________.

a. 15 W

b. 32 W

c. 120 W

d. 480 W

View Answer:

Answer: Option D

Solution:

354. It is simply a single-turn coil of wire that is significantly shorter than one wavelength and carries RF current.

a. turnstile antenna

b. loop antenna

c. rhombic antenna

d. long-wire antenna

View Answer:

Answer: Option B

Solution:

355. A coax has an attenuation of 2.4 dB per 100 ft. The attenuation of 275 ft

a. 2.4 dB

b. 3.3 dB

c. 4.8 dB

d. 6.6 dB

View Answer:

Answer: Option D

Solution:

356. It is group of antenna arrays that when connected together, function as a simple antenna whose beamwidth and direction can be changed electronically without having to physically move any of the individual antennas or antenna elements within the array.

a. end-fire array

b. broadside antenna

c. phased array antenna

d. log-periodic antenna

View Answer:

Answer: Option C

Solution:

357. Conductors in multi-element antennas that do not receive energy directly from the transmission line are known as ______.

a. parasitic element

b. driven element

c. the boom

d. receptor

View Answer:

Answer: Option A

Solution:

358. It is a broadband VHF or UHF antenna that is suited for applications for which radiating circular rather than horizontal or vertical polarized electromagnetic waves are required.

a. discone antenna

b. bicone antenna

c. log-periodic antenna

d. helical antenna

View Answer:

Answer: Option D

Solution:

359. Mode of propagation of helical antenna where electromagnetic radiation is in the direction at right angles to the axis of the helix.

a. normal mode

b. axial mode

c. helix mode

d. helical mode

View Answer:

Answer: Option A

Solution:

360. Mode of propagation of helical antenna where the radiation of the antenna in the axial direction and produces a broadband relatively directional pattern.

a. helical mode

b. normal mode

c. axial mode

d. helix mode

View Answer:

Answer: Option C

Solution:

361. In a Yagi antenna, maximum direction of radiation is toward the

a. director

b. driven element

c. reflector

d. sky

View Answer:

Answer: Option A

Solution:

362. It is defined as the ratio of the antennas maximum gain in the forward direction to its maximum gain in its backward direction

a. side-to-back ratio

b. front-to-side ratio

c. back-to-side ratio

d. front-to-back ratio

View Answer:

Answer: Option D

Solution:

363. The horizontal radiation pattern of a vertical dipole is a ____________.

a. figure of eight

b. circle

c. narrow beam

d. clover leaf

View Answer:

Answer: Option B

Solution:

364. An antenna that provides extremely high gain and directivity and very popular for microwave radio and satellite communications link.

a. helical antenna

b. parabolic antenna

c. hyperbolic antenna

d. log-periodic antenna

View Answer:

Answer: Option B

Solution:

365. Part of a parabolic antenna that houses the primary antenna which radiates electromagnetic waves toward the reflector.

a. feed mechanism

b. focal point

c. center feed

d. feed antenna

View Answer:

Answer: Option A

Solution:

366. It is a passive device that simply reflects the energy radiated by the feed mechanism into a concentrated, highly directional emission in which the individual waves are all in phase with each other.

a. director

b. parabolic segment

c. reflector

d. feed mechanism

View Answer:

Answer: Option C

Solution:

367. The energy near the edge of the parabolic dish that does not reflect but rather is diffracted around the edge of the dish.

a. spillover

b. corona

c. dissipated power

d. copper loss

View Answer:

Answer: Option A

Solution:

368. Determines the angular aperture of the reflector, which indirectly determines how much the primary radiation is reflected by the parabolic dish.

a. numerical aperture

b. V number

c. aperture number

d. aperture angle

View Answer:

Answer: Option C

Solution:

369. For a 2-m diameter parabolic reflector with 10W of power radiated by the feed mechanism operating at 6 GHz with a transmit antenna efficiency of 55% and an aperture efficiency of 55%, determine the beamwidth.

a. 1.25 degrees

b. 2.25 degrees

c. 1.5 degrees

d. 1.75 degrees

View Answer:

Answer: Option D

Solution:

370. Type of feed mechanism where the primary radiating source is located just behind a small opening at the vertex of the paraboloid rather than at the focus.

a. cassegrain feed

b. center feed

c. horn feed

d. antenna feed

View Answer:

Answer: Option A

Solution:

371. Discone radiation pattern is

a. omnidirectional

b. unidirectional

c. figure-of-eight

d. bidirectional

View Answer:

Answer: Option A

Solution:

372. Which is properly terminated antenna?

a. dipole

b. marconi

c. hertz

d. rhombic

View Answer:

Answer: Option D

Solution:

373. An example of a marconi antenna is _______.

a. quarter wave vertical tower

b. collinear

c. yagi

d. rhombic

View Answer:

Answer: Option A

Solution:

374. At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna?

a. minimum voltage and maximum current

b. minimum voltage and minimum current

c. equal voltage and current

d. maximum voltage and minimum current

View Answer:

Answer: Option D

Solution:

375. Radiation resistance is the ratio of ______.

a. radiated power to the antenna center current

b. radiated power to the square of the antenna center current

c. voltage to any point of the antenna

d. square of voltage to the square of current at any point in the antenna

View Answer:

Answer: Option B

Solution:

376. Consists of basic antenna connected to a transmission line plus one or more additional conductors

a. parasitic array

b. directors

c. driven array

d. reflectors

View Answer:

Answer: Option A

Solution:

377. Which of the following is not a driven array?

a. yagi

b. broadside

c. collinear

d. end fire

View Answer:

Answer: Option A

Solution:

378. What is used to determine phase difference between two broadcast antennas?

a. a phase monitor

b. a frequency monitor

c. an amplitude monitor

d. a power monitor

View Answer:

Answer: Option A

Solution:

379. In antennas, which gives more forward gain?

a. reflector

b. driven element

c. parasitic element

d. director

View Answer:

Answer: Option D

Solution:

380. Which of the following is longer?

a. director

b. reflector

c. driven element

d. parasitic element

View Answer:

Answer: Option B

Solution:

381. Which is closer to the driven element?

a. parasitic element

b. driven element

c. director

d. reflector

View Answer:

Answer: Option C

Solution:

382. How much do they differ in length from a half-wavelength?

a. 5%

b. 10%

c. 15%

d. 20%

View Answer:

Answer: Option A

Solution:

383. How much more feed-point impedance does a folded dipole have than a normal dipole?

a. two times as much

b. three times as much

c. four times as much

d. five times as much

View Answer:

Answer: Option C

Solution:

384. How is it possible to produce 70-ohm twin lead?

a. by folding more parasitic element

b. by manufacturing

c. by increasing the radiation resistance

d. by increasing the length of the antenna

View Answer:

Answer: Option B

Solution:

385. With similar size parabolic, plane reflector, and corner-reflector beams, which has greater gain?

a. plane reflector

b. parabolic

c. corner-reflector beam

d. V-beam

View Answer:

Answer: Option B

Solution:

386. With similar size, which has the narrowest lobes?

a. parabolic

b. V-beam

c. corner-reflector beam

d. plane reflector

View Answer:

Answer: Option A

Solution:

387. Why would the wires of V-beam be closer together when used on higher frequencies?

a. main lobe lays farther to wire

b. main lobe lays closer to wire

c. secondary lobes closer to wire

d. secondary lobes farther to wire

View Answer:

Answer: Option B

Solution:

388. How the V-beam is made unidirectional?

a. impedance terminated

b. capacitive terminated

c. inductive terminated

d. resistor terminated

View Answer:

Answer: Option D

Solution:

389. Why might a rhombic be better than a V-beam?

a. it is resistor terminated

b. more acreage needed

c. less acreage needed

d. it is unidirectional

View Answer:

Answer: Option C

Solution:

390. Why is the usual rhombic not frequency – sensitive?

a. unidirectional

b. with its characteristic impedance

c. less acreage required

d. main lobe is greater than back lobe

View Answer:

Answer: Option B

Solution:

391. In what direction is the null of small diameter loop in relation to the plane of the loop?

a. 45 degrees angle

b. 180 degrees angle

c. 360 degrees angle

d. 90 degrees angle

View Answer:

Answer: Option D

Solution:

392. When is a loop unidirectional?

a. when horizontal

b. when vertical

c. when circular

d. when unidirectional

View Answer:

Answer: Option A

Solution:

393. Why are verticals sometimes top-loaded?

a. to resonate on high frequency

b. to decrease the electrical length

c. to resonate on low frequency

d. to look better

View Answer:

Answer: Option C

Solution:

394. Why is pi-network superior to direct coupling to an antenna?

a. reduce harmonic radiation

b. better frequency response

c. better radiation of energy

d. reduce power dissipation

View Answer:

Answer: Option A

Solution:

395. Why might L networks be used between an antenna and transmission line?

a. step impedance up

b. step impedance down

c. better radiation of energy

d. reduce power radiation

View Answer:

Answer: Option A

Solution:

396. Why are antenna ammeters often shorted out or disconnected from the antenna except when readings are desired?

a. to replace it with dummy

b. not to interface with transmission

c. for proper reception of signals

d. to protect from lightning

View Answer:

Answer: Option D

Solution:

397. Device to split transmission line current to two or more antenna towers

a. splitter

b. coupler

c. isolator

d. phasor circuit

View Answer:

Answer: Option D

Solution:

398. What method can be used to determine the feed-point impedance of a vertical antenna?

a. resistance substitution

b. impedance matching

c. dissipated resistance measurement

d. grounding the antenna

View Answer:

Answer: Option A

Solution:

399. In what unit is field intensity measured?

a. volts

b. amperes

c. watts/m

d. mV/m

View Answer:

Answer: Option D

Solution:

400. How fast does low-frequency field strength attenuate?

a. directly proportional to distance

b. inversely proportional to distance

c. directly proportional to time

d. inversely proportional to time

View Answer:

Answer: Option A

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

Complete List of MCQ in Communications Engineering per topic

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