TRANSMISSION LINES QUIZ

Why is impedance matching of a transmission line to antenna important?

• For maximum efficiency

• For maximum time delay

• For maximum power transfer

• For greater energy transformation

The speed at which signals travel down a transmission line

• Velocity factor

• Propagation velocity

• Standing waves

• Reflected waves

What is the meaning of the term velocity factor in a transmission line?

• The index of shielding for a coaxial cable

• The velocity of the wave on the transmission line multiplied by the velocity of light in vacuum

• The ratio of the characteristic impedance of the line to the terminating impedance

• The velocity of the waves on the transmission line divided by the velocity of light in vacuum

What affects the velocity factor in transmission lines?

• The center conductor resistivity

• Dielectrics in the line

• The termination impedance

• The line length

What is the electrical length at 150 MHz for a 2.5m cable with a propagation velocity of 0.85c?

• 1.47m

• 0.68m

Transmission lines are either balanced or unbalanced with respect to:

• Negative terminal

• Ground

• Input

• Positive terminal

Skin effect describes the tendency of:

• DC conductors to carry the circuit current on their surface

• AC conductors to carry the circuit current on their surface

• DC conductors to carry minimum current on their surface

• AC conductors to carry minimum current on their surface

Which of the following is not used for microwave frequencies?

• Coaxial

• Waveguide

• Twin lead

• Strip line

Coaxial cable is not widely used for long microwave transmission lines because of its ___

• High loss

• High cost

• Large size

• Excessive radiation

The characteristic impedance will ___, if the spacing between wires of a balanced transmission line is increased

• Increase

• Decrease

• Remain the same

• Cannot be determined