CWS Antenna Theory & Types 3

Question 1

In a MIMO wireless system, what is spatial multiplexing?

Accepted Answer

Transmitting separate, independent data streams simultaneously over multiple spatial paths to increase throughput

Answer

Broadcasting the same data stream redundantly over multiple antennas for reliability

Answer

Using multiple channels on the same antenna to reduce co-channel interference

Answer

Distributing access points across multiple physical locations in a building

Question 2

What is the primary characteristic of a Yagi-Uda antenna that makes it useful for outdoor wireless links?

Accepted Answer

It is a highly directional antenna offering high gain and a narrow beamwidth

Answer

It provides uniform 360-degree omnidirectional coverage

Answer

It operates exclusively in the licensed spectrum above 6 GHz

Answer

It requires no line of sight between endpoints

Question 3

Why is polarization matching important when aligning antennas in a point-to-point wireless link?

Accepted Answer

To maximize received signal strength and minimize polarization mismatch loss between the link endpoints

Answer

To ensure both antennas operate on the same regulatory frequency band

Answer

To reduce the number of antennas required at each end of the link

Answer

To comply with FCC power limits for licensed point-to-point systems

Question 4

What is the maximum conducted (transmitter output) power permitted by the FCC under Part 15 rules for 2.4 GHz WLAN devices?

Accepted Answer

1 watt (30 dBm)

Answer

100 mW (20 dBm)

Answer

500 mW (27 dBm)

Answer

4 watts (36 dBm)

Question 5

What is beamforming as implemented in 802.11ac and 802.11ax (Wi-Fi 6) wireless standards?

Accepted Answer

Steering the transmitted signal toward specific client devices using phase-shifted antenna arrays to improve signal quality

Answer

Physically reshaping antenna elements to form a beam toward a target client

Answer

Using multiple separate frequency channels to form a broader aggregate beam

Answer

Configuring multiple access points to collectively aim their signals at a common area

Question 6

What is the key difference between a passive antenna and an active antenna system?

Accepted Answer

Active antennas integrate amplifiers or radio transceivers within the antenna assembly, while passive antennas contain only radiating elements without active components

Answer

Passive antennas require battery power while active antennas are powered by the network cable

Answer

Passive antennas work only outdoors while active antennas are designed for indoor use

Answer

Active antennas require manual gain calibration while passive antennas are self-tuning

Question 7

When an antenna specification lists a gain of 6 dBd, approximately what is its gain in dBi?

Accepted Answer

8.15 dBi

Answer

3.85 dBi

Answer

6.00 dBi

Answer

12.00 dBi