Antenna and Propagation Quiz

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Questions and Answers

What is the main advantage of the two-hole directional coupler?

High SWR

Narrow bandwidth

Low directional coupling (correct)

Poor directivity

What is the best device to couple a coaxial line to a parallel-wire line?

Quarter-wave transformer

Slotted line

Directional coupler

Balun (correct)

What is the name of the method used to determine antenna impedance?

Stub matching

Reactance circle

Smith chart (correct)

Trial and error

What type of antenna has a unity gain?

Isotropic Signup and view all the answers

What is the velocity factor of a transmission line?

The velocity of the wave on the transmission line divided by the velocity of light in a vacuum Signup and view all the answers

What type of transmission line consists of two conductors that have equal resistance per unit length?

Balanced line Signup and view all the answers

What does EIRP stand for?

Effective isotropic radiated power Signup and view all the answers

Which of the following is not a common transmission line impedance?

120 Ω Signup and view all the answers

What is the smallest beam of a satellite antenna's radiation pattern?

Spot beam Signup and view all the answers

What is the region in front of a parabolic antenna?

All of these Signup and view all the answers

What is the relationship between the characteristic impedance of the line (Zo) and the load impedance (Zl) for maximum absorption of power at the antenna?

Zo = ZL Signup and view all the answers

What type of antenna can only receive a television signal?

TVRO Signup and view all the answers

What determines the characteristics of a transmission line?

Physical dimensions Signup and view all the answers

What is the standing-wave ratio (SWR) when a 50 Ω coax is connected to a 73 Ω load?

1.46 Signup and view all the answers

What is the radiation pattern of a discone?

Omnidirectional Signup and view all the answers

What is the product of the power supplied to an antenna and its gain relative to a half-wave dipole?

ERP Signup and view all the answers

What is the measure of superiority of a material over a vacuum as a path of magnetic lines of force?

Permeability Signup and view all the answers

What is the name of the transmission line that uses ground return?

Grounded line Signup and view all the answers

What is the characteristic impedance of a transmission line independent of?

Length Signup and view all the answers

What is the most commonly used transmission line?

Coax Signup and view all the answers

What happens when the terminating impedance is exactly equal to the characteristic impedance of the transmission line?

The return loss is zero Signup and view all the answers

What is the permeability of free space equal to?

1.257 x 10-6 henry/meter Signup and view all the answers

What is the impedance of a balance 4-wire with a diameter of 0.25cm and spaced 2.5 cm apart using an insulator with a dielectric constant of 2.56?

75 ohms Signup and view all the answers

What is the impedance of the matching section when matching a 73-ohm antenna to a 600 ohm polyethylene coaxial feeder line?

209.28 ohms Signup and view all the answers

Study Notes

Antennas and Transmission Lines

Circular polarization is a type of antenna polarization.

Antenna Impedance and Radiation Pattern

Unity gain antenna is a half-wave dipole.
EIRP stands for Effective Isotropic Radiated Power.
Spot beam is the smallest beam of a satellite antenna's radiation pattern.
A region in front of a parabolic antenna is known as the Fresnel zone.
A TVRO is a type of antenna that can only receive a television signal.
Radiation pattern of a discone is omnidirectional.
Major lobe radiation refers to the concentration of radio waves in the direction of the signal emitted by a directional antenna.

Antenna Arrays and Components

Reflector and director of an antenna array are considered parasitic elements.
The product of the power supplied to the antenna and its gain relative to a half-wave dipole in a given direction is known as ERP.

Antenna Design and Characteristics

Adding C in series or top loading can make an antenna physically long electronically short.
The capture area of an antenna is directly proportional to the wavelength squared.
Velocity factor of a transmission line is the ratio of the velocity of the wave on the transmission line to the velocity of light in a vacuum.

Transmission Lines

A balun is used to couple a coaxial line to a parallel-wire line.
The velocity factor of a transmission line is the ratio of the velocity of the wave on the transmission line to the velocity of light in a vacuum.
A balanced line consists of two conductors with equal resistance per unit length.
Common transmission line impedances include 50 Ω, 75 Ω, and 120 Ω.
For maximum absorption of power at the antenna, the characteristic impedance of the line (Zo) should be equal to the load impedance (Zl).

Transmission Line Characteristics

Twin lead is also referred to as an open pair.
The standing-wave ratio is a ratio expressing the percentage of incident voltage reflected on a transmission line.
Termination refers to the load connected to the output end of a transmission line.

Electrical Properties of Materials

Permeability is a measure of a material's superiority over a vacuum as a path for magnetic lines of force.
The permeability of free space is 1.257 x 10-6 henry/meter.

Common Transmission Lines

Coaxial cable is the most commonly used transmission line.
The characteristic impedance of a transmission line does not depend on its length.

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Description

Test your knowledge of antenna and propagation concepts, including impedance, polarization, and gain. Covers topics like EIRP and isotropic radiated power.