WorksheetsAntennas
Total questions: 17
Worksheet time: 39mins
What is the primary function of the receiver in a wireless communication system?
Generate information to send
Convert signals into human speech
Overcome signal modifications and deliver information
Amplify the transmitted noise
Which of the following is considered multiplicative noise in a wireless channel?
Thermal noise
Reflection from smooth surfaces
Cosmic radiation
Interference from other transmitters
What are the three types of fading that occur in wireless communication channels?
Thermal, Doppler, and Rayleigh
Additive, multiplicative, and subtractive
Path loss, shadowing, and fast fading
Refraction, diffraction, and scattering
Which phenomenon causes signal distortion due to the edges of objects like rooftops and hilltops?
Absorption
Reflection
Diffraction
Refraction
What causes an electric field to be produced in space according to Maxwell’s equations?
A stationary charge only
A time-varying magnetic field
A static magnetic field
A constant electric potential
What is the direction of the Poynting vector in a plane electromagnetic wave?
Perpendicular to both the E and H fields
Parallel to the electric field only
Along the magnetic field direction
In the opposite direction of the electric field
What property defines the polarization of a plane electromagnetic wave?
The direction of the magnetic field
The magnitude of the wave
The alignment of the electric field vector
The Poynting vector amplitude
What type of polarization results from the combination of two orthogonal linearly polarized waves with a 90° phase difference?
Linear polarization
Unpolarized wave
Circular polarization
Elliptical polarization
What happens to the amplitude of an electromagnetic wave in a lossy medium?
It increases linearly
It stays constant
It diminishes exponentially
It oscillates unpredictably
What is the unit of the attenuation constant α?
Volts per meter (V/m)
Siemens per meter (S/m)
Meters per second (m/s)
Inverse meters (m⁻¹)
What does the axial ratio (AR) describe in an elliptically polarized wave?
Ratio of electric to magnetic field
Ratio of signal to noise
Ratio of maximum to minimum electric field amplitude
Ratio of wave speed in different media
Which polarization allows for reliable satellite communication regardless of antenna orientation?
Linear vertical polarization
Linear horizontal polarization
Unpolarized radiation
Circular polarization
What is the primary role of an antenna in an RF system?
To amplify signals from the transmitter
To store electrical energy for future use
To convert guided waves into radiating waves (and vice versa)
To measure electromagnetic interference
Which of the following scenarios results in electromagnetic radiation from a conductor?
Uniform motion of charges in a straight wire
Stationary charges on a wire
Charges reaching the end of a wire and reversing direction
Constant DC current in a loop
What is the condition for maximum power transfer from a transmitter to an antenna?
The antenna and transmitter are physically aligned
The antenna’s input reactance is zero
The antenna impedance is the complex conjugate of the source impedance
The antenna has the highest possible gain
According to the reciprocity theorem, which of the following is true about antennas?
An antenna works only for transmission, not reception
Antenna gain differs in transmission and reception
Radiation pattern remains the same for transmit and receive modes
Radiation efficiency is always 100%
Obtain the field pattern for a dipole of length Lambda/2.
Find the length of a wire carrying a current of 6 A peak at 1.5 MHz. The field strength measured at a distance 20 km in direction at right angles to the area of wire is 0.5 mv/m. The wire is being situated in free space.
