Why antennas matter

In WLAN systems, antenna placement and RF environment often have a greater impact on performance than radio settings. Most throughput and stability issues are caused by poor antenna deployment.

Common antenna mistakes

1. Placement near metal structures

Omni antennas installed near ducts, grids or reflectors cause reflections and multipath distortion, reducing data rates and stability.

2. Antennas partially inside metal surfaces

Dipoles passing through metal panels become detuned. Radiation pattern and efficiency are degraded.

3. Unknown mounting materials

Placing antennas on materials with high permittivity detunes the antenna and shifts resonance.

4. High ceiling with omni antennas

Energy is directed sideways instead of towards users, increasing co-channel interference and reducing effective coverage.

5. High-gain omni on ceiling

Narrow vertical beam causes overshooting and interference between cells.

6. Antenna next to wall

Half of the radiation pattern is lost into the wall, reducing usable gain.

7. Wrong mounting orientation

Ceiling antennas installed on walls distort the radiation pattern and degrade coverage.

8. Conductive coating

Metallic paint introduces attenuation and reduces antenna efficiency.

9. Devices inside metal enclosures

Detuning and shielding cause severe attenuation (>10 dB).

10. Human body attenuation

Hand and head absorption significantly affect handheld and VoIP devices.

Practical RF guidelines

• Keep antennas away from conductive objects.
• Understand radiation patterns and aim energy towards users.
• Do not hide antennas above ceilings.
• Match antenna type to mounting height and environment.
• Use directional antennas in high ceiling environments.
• Ensure full MIMO chain support.
• Adjust transmit power according to antenna gain.

In real deployments, antenna placement directly affects SNR, which determines throughput and stability.