MCQ in Microwave Communications Part 8 | ECE Board Exam

This is the Multiples Choice Questions Part 8 of the Series in Microwave Communications 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.

MCQ Topic Outline included in ECE Board Exam Syllabi

• MCQ in Basic Principles of Microwave Communications
• MCQ in Electro-Optics
• MCQ in Photonics
• MCQ in Optoelectronics
• MCQ in Electromagnetics
• MCQ in Avionics, Aerospace, Navigational and Military Applications
• MCQ in Medical Electronics
• MCQ in Cybernetics
• MCQ in Biometrics

Continue Practice Exam Test Questions Part 8 of the Series

351. What are limits of microwaves?

a) 1 – 25,000 GHz

b) 1 – 50,000 GHz

c) 1 – 75,000 GHz

d) 1 – 100,000 GHz

352. The following transmission lines are used for microwave frequencies, except:

a) waveguide

b) twin lead

c) coax

d) stripline

353. How much must a waveguide be?

a) over a half-wave

b) over a quarter-wave

c) over a wavelength

d) over three-fourths of a wavelength

354. How high must a waveguide be?

a) over a wavelength

b) over a quarter wave

c) over a half wave

d) over two wavelengths

355. What is the designation of the lowest-frequency microwave band?

a) V band

b) X band

c) Ku band

d) L band

356. What is the designation of the highest-frequency microwave band?

a) R band

b) Ka band

c) V band

d) L band

357. What is reduced by using choke flanges?

a) refraction

b) reflection

c) absorption

d) cancellation

358. What is the name of the microwave transmission line that is used in printed circuits?

a) microstrip

b) coax

c) twin lead

d) twisted pair

359. Where is the resistive load placed in a directional coupler?

a) front end of the primary

b) front end of the secondary

c) back end of the primary

d) back end of the secondary

360. One of the following is a type of bolometer

a) calorimeter

b) thermocouple

c) barreter

d) carreter

361. Why are bolometers not used to detect modulation?

a) thermal sluggishness

b) inefficiency

c) less accurate

d) less precise

362. The advantage of a resonant cavity over a hairpin tank?

a) lesser Q

b) wider bandwidth

c) higher Q

d) efficiency

363. What type of coupling is used between a waveguide and a waveguide wavemeter?

a) loop antenna

b) quarterwave antenna

c) hole

d) E probe

364. Which microwave tube has a repeller?

a) TWT

b) Klystron

c) Magnetron

d) BWO

365. Which microwave tube has a series of cavities?

a) magnetron

b) klystron

c) TWT

d) BWO

366. Which microwave tube has a helix

a) klystron

b) magnetron

c) multicavity klystron

d) BWO

367. Which microwave tube has a horseshoe magnet?

a) magnetron

b) klystron

c) TWT

d) BWA

368. What is the advantage of a gridless klystron

a) power input

b) gain

c) attenuator

d) power output

369. Which vacuum tube do you think oscillate at the highest frequency

a) Magnetron

b) Gunn

c) Klystron

d) BWO

370. How would a balun be used to change 200 ohms to 50 ohms?

a) use a higher turns ratio

b) use a higher frequency

c) reverse it

d) use low frequency

371. How could a balun change 100 ohms to 900 ohms

a) use 3:1 turns ratio

b) use 1:3 turns ratio

c) use 9:1 turns ratio

d) use 1:9 turns ratio

372. How high a frequency can transistor generate?

a) above 10 GHz

b) above 5 GHz

c) above 2 GHz

d) above 7.8 GHz

373. What is the microwave application of a varactor?

a) mixer

b) frequency multiplier

c) demodulator

d) demultiplexer

374. What diode does better than varactor in microwave frequencies?

a) step recovery

b) tunnel

c) PIN

d) Gunn

375. The following diodes can generate microwave AC except:

a) Tunnel

b) LSA

c) IMPATT

d) Magnetron

376. For what are PIN diodes used in microwave?

a) mixers

b) modulators

c) oscillators

d) amplifier

377. What is the other name for LSA diodes?

a) negative resistance

b) bulk-effect

c) tunneling effect

d) time-space

378. What is the advantage of LSA over a Gunn Diode?

a) more efficient

b) higher power

c) less noise

d) higher frequency

379. What is wrong with the term Gunn Diode?

a) not a gun

b) not a semiconductor

c) not a diode

d) should be spelled with single “n”

380. What is important property do ferrites have which is used as a switch?

a) faraday rotation

b) resonance absorption

c) magnetic properties

d) high curie temperature

381. Which is used in circulators?

a) resonance absorption

b) magnetic properties

c) ion resonance

d) faraday rotation

382. What is the advantage of using a circulator with two transmitter and two receivers?

a) many antennas

b) less interference

c) easy coupling

d) one antenna only

383. To what must the fourth port be connected in a tunnel diode amplifier?

a) resistor

b) inductor

c) capacitor

d) impedance

384. To what must the third port be connected in a multiplexer circulator

a) reflecting short circuit

b) absorbing short circuit

c) reflecting open circuit

d) absorbing open circuit

385. What does radar mean?

a) radio detection and range

b) radio direction and radiation

c) radio direction and range

d) range direction radiation

386. In what distance unit are marine radars calibrated?

a) statute miles

b) kilometers

c) nautical miles

d) feet

387. What time unit is the equivalent of a radar mile?

a) 12.3 microseconds

b) 6.8 microseconds

c) 4.5 microseconds

d) 7.1 microseconds

388. In what frequency band does marine radar operate?

a) 9.5 GHz S band

b) 3 GHz X band

c) 9.5 GHz Ku band

d) 3 GHz S band

389. To what two circuits would a radar timer circuit feed signals?

a) modulator and mixer

b) amplifier and circulator

c) modulator and circulator

d) amplifier and modulator

390. What is the target display on a CRT called?

a) crosshair

b) blip

c) center spot

d) round

391. What is the main bang on a PPI radar set?

a) blip

b) center spot

c) bearing

d) round

392. What is the ability to separate adjacent equidistant targets called?

a) bearing resolution

b) narrow bandwidth

c) high frequency

d) shorter wavelength

393. What is the approximate rotational rate of a radar antenna?

a) 20 rpm

b) 5 rpm

c) 25 rpm

d) 10 rpm

394. How is radar CRTs differ from TV?

a) square

b) round

c) rectangular

d) trapezoidal

395. What circuits make up the radar transmitter?

a) multivibrator

b) trapezoidal oscillator

c) sine wave generator

d) blocking oscillator

396. What type of oscillator determines the PRR?

a) blocking

b) pulse

c) square

d) blocking or pulse

397. What other circuit might be used as an oscillator that determines the PRR?

a) trapezoidal generator

b) unbalanced multivibrator

c) bistable multivibrator

d) sinewave generator

398. Why are hydrogen-gas thyratrons used in radar?

a) fast-ionize

b) cheaper

c) accurate

d) efficient

399. What is the other name for a pulse-forming network in radars?

a) tuned circuit

b) oscillators

c) delay line

d) capacitive circuits

400. What determines the PRR in odd-time radar sets?

a) tuned circuit frequency

b) oscillator frequency

c) spark gap speed

d) MOPA transmitter time

Questions and Answers in Microwave Communications and Principles Series

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

Complete List of MCQ in Communications Engineering per topic