AP7131 facade antenna vs. rubber whip

E Efrem Robinson 3 years 7 months ago
1 3 0

Does anyone have any real world info on the difference in performance/coverage I could expect when using a tri-radio AP7131 with the built-in facade antenna vs. using 6 of the rubber (plastic) whip antenna ML-2452-APA2-01??? The environment is carpeted office space.

Thanks in advance....

Efrem Robinson

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3 Replies

R Ritesh Patel

Hi Efrem,

I do not have any performance/coverage data to share at this point but I do hope that my long answer to your question actually answers your question.

Based on following antenna parameters I believe certain conclusion can be drawn.

1. Max Gain Facade: 3dbi / 5 dbi ML-2452-APA2-01: 6 dbi / 7 dbi

2. Beamwidth Azimuth Facade: 360 degrees ML-2452-APA2-01: 360 degrees

Elevation Facade: 90 degrees ML-2452-APA2-01: 35 degrees

It is necessary first to understand that Gain is a measurement of concentration of power/energy from an antenna when compared to the radiating energy of an isotropic radiating element.  Simply, higher the gain more the antenna concentrates the energy that is being radiated. Energy is concentrated over a given area based on the design of an antenna and is defined by the RF pattern of an antenna in horizontal and vertical plane.

In case of the Facade antenna, note that the gain is less compared to the dipole antenna.  This means that the energy will be less concentrated compared to the dipole antenna.

Here it is important to note that the Elevation beamwidth of the facade antenna is higher than the dipole antenna.  This shows that the RF energy through use of the facade antenna will be spread over a greater angle in the vertical plane compared to the dipole antenna.  You can also say that the dipole antenna concentrates/focuses energy more in the elevation plane compared to the facade antenna.

Therefore, when comparing facade (which is a patch and not a dipole antenna) vs. dipole antenna it can be concluded that using the dipole antenna the RF energy will be spread more horizontally compared to the facade antenna (since energy is being squeezed more vertically) at a cost of less energy spread in the vertical plane.  This will allow an increase of coverage area in the horizontal plane.

One thing to also note here is that the Patch antennas, similar to or with higher gain than facade antenna, are more designed to provide coverage in half of a plane (usually vertical plane) than in the entire plane which is the case for dipole antenna.  So when the patch antenna is mounted on the ceiling the RF coverage is expected to be more in the area underneath the antenna (below the ceiling) and not above the antenna (over the ceiling). Please also refer to the antenna guide v. 1.5

K Keith Bray

FYI, the LANPlanner team is working with hardware engineering in San Jose to get the full details of the facade antenna modeled correctly in LANPlanner.  We hope to have something by mid to end of next week.  Once we have that you will be able to get some pretty side-by-side predictive comparison screenshots of the coverage in various facility layouts.  Feel free to ping me next week for an update. -KB

K Keith Bray

LANPlanner version 12.1.1 is available, and it now has both the facade antenna and the rubber ducky antenna versions of the 7131(N) modeled in the software as part of the shipping defaults.  Using LANPlanner you can visualize the difference in signal strength coverage for the two different AP configurations for the same environment model.  If anyone needs assistance obtaining a copy of LANPlanner (zero-cost for internal Motorolans using the tool for sales demonstration purposes), please visit http://compass.mot.com/go/lanplanner  for details, and you may also email RFSoftwareContact@motorola.com for assistance. -KB

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