# Antenna and Wave Propagation 1

Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject: Antenna and Wave Propagation 1

Part 1: List for questions and answers of Antenna & wave Propagation

Q1. A rectangular horn antenna operating at 4GHz has the wavelength of 0.075m and gain of about 13dBi. What will be its required capture area?

a) 0.0149 m^2

b) 0.0475 m^2

c) 0.5521 m^2

d) 0.9732 m^2

Q2. Which mode of radiation occurs in an helical antenna due to smaller dimensions of helix as compared to a wavelength?

a) Normal

b) Axial

c) Both a and b

d) None of the above

Q3. By how many times is an input impedance of a folded dipole at resonance greater than that of an isolated dipole with same length as one of its sides?

a) 2

b) 3

c) 4

d) 6

Q4. How do the elements of an active region behave?

a) Inductive

b) Capacitive

c) Resistive

d) None of the above

Q5. In an electrically large loop, an overall length of the loop is equal to ______

a) λ /2

b) λ

c) λ /10

d) λ /50

Q6. What is/are the major applications of an infinitesimal dipole that contribute/s to its analysis?

a) Field pattern estimation due to any length of antenna

b) Improvement in radiation resistance by increasing dipole length

c) Both a and b

d) None of the above

Q7. A dipole carries r.m.s. current of about 300A across the radiation resistance 2 ?. What would be the power radiated by an antenna?

a) 90 kW

b) 135 kW

c) 180 kW

d) 200 kW

Q8. If J and M are active at the same time, which principle theorem is used for field estimation?

a) Reciprocity

b) Superposition

c) Causality

d) Relativity

Q9. The concept of magnetic vector potential finds its major application in deriving expression of magnetic field intensity especially for ______

a) Real fields

b) Imaginary fields

c) Complex fields

d) None of the above

Q10. Which among the below mentioned magnetic quantities is/are dependent on media/medium?

a) B

b) H

c) Both a and b

d) None of the above

Q11. In solution evaluation process of inhomogeneous vector potential wave equation, if points are completely removed from the source, then by which factor does the time varying field and static solution differ?

a) e^-jkr

b) e^jkr

c) e^-jk/r

d) e^(jk + r)

Q12. Self impedance of an antenna is basically __________

a) Its input impedance during the removal of all other antennas

b) Its impedance by taking into consideration the consequences of other antennas

c) Both a and b

d) None of the above

Q13. Which property of antenna is/are likely to be evidenced in accordance to Reciprocity theorem?

a) Equality of impedances

b) Equality of directional patterns

c) Equality of effective lengths

d) All of the above

Q14. Under which conditions of two unit vectors, the polarization loss factor (PLF) is equal to unity?

a) Perpendicular

b) Perfectly aligned

c) Angle inclination (?p)

d) All of the above

Q15. If an antenna draws 12 A current and radiates 4 kW, then what will be its radiation resistance?

a) 22.22 ohm

b) 27.77 ohm

c) 33.33 ohm

d) 39.77 ohm

Q16. In radio communication link, what is the shape/nature of waves generated by transmitting antenna?

a) Spherical

b) Plane

c) Triangular

d) Square

Q17. What is the functioning role of an antenna in receiving mode?

b) Converter

c) Sensor

d) Inverter

Q18. In lens antenna, what kind of wave energy is transformed into plane waves?

a) Convergent

b) Divergent

c) Contingent

d) Congruent

Q19. According to Secant law, which frequency is greater than critical frequency by a factor of secθi

a) MUF

b) LUF

c) OWF

d) UHF

Q20. Which layer has the atmospheric conditions exactly opposite to that of standard atmosphere?

a) Depression layer

b) Regression layer

c) Inversion layer

d) Invasion layer

Part 1: List for questions and answers of Antenna & wave Propagation