Antenna Theory and Design MCQs

1. Which of the following properties of an antenna determines its directivity? A) Gain B) Polarization C) Efficiency D) Beamwidth Answer: A) Gain 2. What is the term for the ability of an antenna to concentrate radiation in a particular direction? A) Efficiency B) Beamwidth C) Directivity D) Polarization Answer: C) Directivity 3. Which type of antenna consists of a straight conducting wire or rod? A) Horn antenna B) Dipole antenna C) Yagi-Uda antenna D) Parabolic antenna Answer: B) Dipole antenna 4. What is the impedance of a half-wave dipole antenna in free space? A) 50 ohms B) 75 ohms C) 300 ohms D) 600 ohms Answer: A) 50 ohms 5. Which antenna parameter is a measure of how well the antenna radiates power? A) Gain B) Impedance C) Polarization D) VSWR (Voltage Standing Wave Ratio) Answer: A) Gain 6. Which antenna type is commonly used for satellite communication due to its high gain and narrow beamwidth? A) Yagi-Uda antenna B) Log-periodic antenna C) Parabolic (dish) antenna D) Loop antenna Answer: C) Parabolic (dish) antenna 7. What is the purpose of a balun in antenna systems? A) To balance the antenna’s impedance B) To increase the antenna’s directivity C) To reduce the antenna’s size D) To improve the antenna’s bandwidth Answer: A) To balance the antenna’s impedance 8. Which parameter describes the ability of an antenna to maintain a constant radiation pattern over different frequencies? A) Bandwidth B) Beamwidth C) Efficiency D) VSWR (Voltage Standing Wave Ratio) Answer: A) Bandwidth 9. Which antenna design is characterized by its wide bandwidth and omnidirectional radiation pattern? A) Log-periodic antenna B) Horn antenna C) Loop antenna D) Helical antenna Answer: A) Log-periodic antenna 10. What is the typical input impedance of a folded dipole antenna? A) 50 ohms B) 75 ohms C) 300 ohms D) 600 ohms Answer: C) 300 ohms 11. Which parameter of an antenna describes its ability to radiate efficiently in a specific direction? A) Polarization B) Efficiency C) Directivity D) Impedance Answer: C) Directivity 12. Which antenna type is known for its circular polarization, making it suitable for satellite communication and GPS? A) Yagi-Uda antenna B) Parabolic (dish) antenna C) Helical antenna D) Log-periodic antenna Answer: C) Helical antenna 13. What is the purpose of a ground plane in a monopole antenna? A) To increase the antenna’s directivity B) To reduce the antenna’s size C) To balance the antenna’s impedance D) To provide a reference point for radiation Answer: D) To provide a reference point for radiation 14. Which antenna characteristic describes how sensitive the antenna is to signals arriving from different directions? A) Directivity B) Gain C) Beamwidth D) Polarization Answer: A) Directivity 15. Which antenna design is often used in RFID systems due to its small size and omnidirectional radiation pattern? A) Loop antenna B) Yagi-Uda antenna C) Horn antenna D) Patch antenna Answer: D) Patch antenna 16. What is the primary function of a reflector in a parabolic antenna? A) To convert RF signals to digital signals B) To provide structural support for the antenna C) To amplify the received signals D) To focus RF signals onto the feed element Answer: D) To focus RF signals onto the feed element 17. Which type of antenna is commonly used for TV reception due to its high gain and directionality? A) Loop antenna B) Yagi-Uda antenna C) Dipole antenna D) Helical antenna Answer: B) Yagi-Uda antenna 18. What is the main advantage of using a phased array antenna system? A) Increased bandwidth B) Reduced power consumption C) Electronic beam steering D) Higher efficiency Answer: C) Electronic beam steering 19. Which antenna characteristic describes the range of frequencies over which the antenna operates effectively? A) Efficiency B) Bandwidth C) Impedance D) Beamwidth Answer: B) Bandwidth 20. What is the approximate radiation pattern of a dipole antenna in free space? A) Omnidirectional B) Bidirectional C) Unidirectional D) Spheroidal Answer: B) Bidirectional 21. Which type of antenna is characterized by its horn-shaped structure and is commonly used for microwave applications? A) Yagi-Uda antenna B) Parabolic (dish) antenna C) Horn antenna D) Log-periodic antenna Answer: C) Horn antenna 22. What is the primary purpose of a ground plane in a monopole antenna? A) To increase the antenna’s directivity B) To reduce the antenna’s size C) To balance the antenna’s impedance D) To enhance the antenna’s radiation efficiency Answer: D) To enhance the antenna’s radiation efficiency 23. Which parameter of an antenna describes the ability to withstand voltage standing wave ratio (VSWR) mismatches? A) Gain B) Polarization C) Impedance D) VSWR Answer: D) VSWR 24. Which antenna type is known for its ability to transmit and receive signals equally well in all directions? A) Dipole antenna B) Loop antenna C) Isotropic antenna D) Parabolic antenna Answer: C) Isotropic antenna 25. What is the primary function of a feed horn in a parabolic antenna system? A) To reflect signals onto the dish B) To receive signals and convert them to RF signals C) To focus signals onto the parabolic reflector D) To minimize interference from other signals Answer: C) To focus signals onto the parabolic reflector 26. Which antenna design is commonly used for cellular base station antennas due to its ability to provide sector coverage? A) Yagi-Uda antenna B) Patch antenna C) Sector antenna D) Log-periodic antenna Answer: C) Sector antenna 27. Which of the following is a method to improve the bandwidth of an antenna? A) Increase the antenna’s directivity B) Decrease the antenna’s size C) Use a wider range of frequencies D) Reduce the antenna’s impedance Answer: C) Use a wider range of frequencies 28. What is the primary advantage of using a log-periodic antenna over a dipole antenna? A) Higher gain B) Broader bandwidth C) Lower cost D) Smaller size Answer: B) Broader bandwidth 29. Which parameter of an antenna is typically measured in dBi (decibels relative to isotropic)? A) Efficiency B) Directivity C) Polarization D) Impedance Answer: B) Directivity 30. Which antenna characteristic is defined as the angle between half-power points on the radiation pattern? A) Gain B) Beamwidth C) Efficiency D) Polarization Answer: B) Beamwidth 31. Which type of antenna is commonly used for radar applications due to its narrow beamwidth and high gain? A) Patch antenna B) Yagi-Uda antenna C) Parabolic (dish) antenna D) Helical antenna Answer: C) Parabolic (dish) antenna 32. What is the primary function of a ground plane in a monopole antenna? A) To increase the antenna’s directivity B) To reduce the antenna’s size C) To balance the antenna’s impedance D) To provide a reference plane for radiation Answer: D) To provide a reference plane for radiation 33. Which parameter of an antenna describes the ability to handle power without significant losses? A) Efficiency B) Bandwidth C) Power handling capability D) Directivity Answer: C) Power handling capability 34. Which antenna type is known for its ability to radiate and receive signals equally well in all directions? A) Dipole antenna B) Loop antenna C) Isotropic antenna D) Parabolic antenna Answer: C) Isotropic antenna 35. What is the function of a director element in a Yagi-Uda antenna? A) To reflect signals back to the driven element B) To amplify received signals C) To improve the antenna’s bandwidth D) To minimize interference from other signals Answer: A) To reflect signals back to the driven element 36. Which antenna parameter is a measure of how well the antenna converts electrical signals into electromagnetic waves? A) Gain B) Efficiency C) Directivity D) Polarization Answer: B) Efficiency 37. Which antenna design is characterized by its circular polarization, making it suitable for satellite communication and GPS? A) Yagi-Uda antenna B) Parabolic (dish) antenna C) Helical antenna D) Log-periodic antenna Answer: C) Helical antenna 38. Which parameter of an antenna describes its ability to concentrate radiation in a particular direction? A) Efficiency B) Beamwidth C) Directivity D) Polarization Answer: C) Directivity 39. What is the typical input impedance of a folded dipole antenna? A) 50 ohms B) 75 ohms C) 300 ohms D) 600 ohms Answer: C) 300 ohms 40. Which type of antenna is commonly used for RFID systems due to its small size and omnidirectional radiation pattern? A) Loop antenna B) Yagi-Uda antenna C) Horn antenna D) Patch antenna Answer: D) Patch antenna

Antenna Theory and Design MCQs

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