Microwave Engineering – MCQs

1. : What frequency range is typically considered as microwave?
(A) 1 Hz to 100 Hz
(B) 300 Hz to 3 kHz
(C) 300 MHz to 300 GHz
(D) 3 GHz to 30 GHz

2. : Which component is used for isolating microwave components?
(A) Directional coupler
(B) Isolator
(C) TWT
(D) Klystron

3. : Which waveguide mode has the lowest cutoff frequency?
(A) TE01
(B) TE10
(C) TM11
(D) TM01

4. : What is the main disadvantage of waveguides?
(A) High loss
(B) Bulky size
(C) High attenuation
(D) Low power handling

5. : Which of the following is a microwave semiconductor device?
(A) BJT
(B) FET
(C) Gunn diode
(D) Zener diode

6. : Reflex klystron is mainly used as a:
(A) Oscillator
(B) Amplifier
(C) Filter
(D) Mixer

7. : The function of a circulator is to:
(A) Block signals
(B) Allow signal flow in one direction only
(C) Mix signals
(D) Distribute power equally

8. : S-parameters are used in:
(A) Low-frequency analysis
(B) Power analysis
(C) Microwave network analysis
(D) Antenna analysis only

9. : A two-port device with no energy storage is called:
(A) Passive
(B) Active
(C) Linear
(D) Non-linear

10. : Which microwave tube is used for amplification in radar systems?
(A) Magnetron
(B) Klystron
(C) TWT
(D) IMPATT

11. : The dominant mode in rectangular waveguide is:
(A) TM11
(B) TE11
(C) TE10
(D) TM10

12. : What is the unit of VSWR (Voltage Standing Wave Ratio)?
(A) Ohms
(B) dB
(C) Unitless
(D) Volts

13. : A Smith chart is used for:
(A) Voltage calculations
(B) Time-domain analysis
(C) Impedance matching
(D) Current calculations

14. : A device that allows signals to pass in one direction and blocks in reverse is called:
(A) Modulator
(B) Attenuator
(C) Isolator
(D) Amplifier

15. : The main application of a magnetron is in:
(A) Microwave oven
(B) Wireless LAN
(C) Satellite
(D) Fiber optics

16. : What is the purpose of a directional coupler?
(A) To split power equally
(B) To detect standing waves
(C) To couple a defined amount of signal power
(D) To oscillate signals

17. : The wavelength in a waveguide is:
(A) Same as in free space
(B) Always larger than free space
(C) Always smaller than free space
(D) Depends on frequency and dimensions

18. : Microwave frequencies are generally generated using:
(A) ICs
(B) Microprocessors
(C) Microwave tubes and special diodes
(D) MOSFETs

19. : What is the typical impedance of a rectangular waveguide?
(A) 25 ohms
(B) 50 ohms
(C) 100 ohms
(D) Depends on mode and frequency

20. : Ferrite materials are often used in:
(A) Oscillators
(B) Microwave circulators and isolators
(C) Frequency mixers
(D) Waveguide windows

21. : The insertion loss of an ideal microwave isolator is:
(A) Zero
(B) High
(C) Infinite
(D) One

22. : Microwave signals are typically transmitted via:
(A) Twisted pair
(B) Coaxial cable
(C) Waveguides and antennas
(D) Optical fiber

23. : Which of the following parameters describes power handling in a microwave component?
(A) S11
(B) Insertion loss
(C) VSWR
(D) Power rating

24. : What does the Q-factor of a microwave cavity indicate?
(A) Resistance
(B) Capacitance
(C) Energy storage efficiency
(D) Radiation efficiency

25. : What is the cutoff wavelength in a waveguide?
(A) Shortest possible wavelength
(B) Wavelength below which wave cannot propagate
(C) Wavelength above which wave cannot propagate
(D) Maximum voltage wavelength