RF Fundamentals & Signal Propagation Flashcards

Which antenna characteristic describes the angular range over which the antenna radiates at least half its maximum power?

Answer: Beamwidth

Beamwidth is the angular measure of the antenna's radiation pattern at the -3 dB (half-power) points.

What is the noise floor in a wireless receiver typically expressed as?

Answer: dBm (negative value)

The noise floor is the lowest detectable signal level, expressed as a negative dBm value representing thermal and system noise.

Which propagation behavior occurs when a radio wave hits a large flat surface and bounces back at an angle equal to the angle of incidence?

Answer: Reflection

Reflection occurs when radio waves strike a smooth, large surface and bounce off at the same angle as the incoming wave.

What does a link budget analysis calculate to determine if a wireless link will function reliably?

Answer: Received signal level versus receiver sensitivity

A link budget compares the expected received signal level (after all gains and losses) against the receiver's minimum sensitivity threshold.

Which of the following best describes the effect of antenna polarization mismatch between transmitter and receiver?

Answer: Reduced signal strength (polarization loss)

Polarization mismatch between transmitting and receiving antennas causes polarization loss, typically up to 3 dB or more of signal degradation.

What is the primary advantage of using MIMO (Multiple Input Multiple Output) antennas in 802.11n/ac/ax?

Answer: Improved throughput and link reliability using multipath

MIMO exploits multipath propagation to transmit multiple data streams simultaneously, increasing throughput and improving link reliability.