Beam Pattern Set Download
Fidelity Comtech is pleased to provide the pattern set download to enhance the design options and performance of your Phocus Array 802.11 wireless system
The following pattern sets are included in this download:
- 90 Degree Beam Pattern Set
- 180 Degree Beam Pattern Set
- Figure Eight Beam Pattern Set
If your Phocus Array is running a version of 2.1.x firmware, please select the following download files,
If your Phocus Array is running a version of 2.2.x firmware, please select the following download files,
Beam Pattern Set Application Notes
Selecting an Appropriate Pattern for the Phocus Array™ System
The Fidelity Comtech Phocus Array™ System has a phased array antenna that can shape the radiation contour, or “pattern”, emitted by the antenna. Possible patterns range from an omni directional pattern (the same signal strength in every direction) to directional patterns (maximizing the signal strength in one direction). This application note discusses Fidelity Comtech’s current library of general purpose patterns and how to select the right one for a particular application.
The current pattern library contains the following pattern types: omni directional, high gain directional patterns (co-phase patterns), low side lobe directional patterns, 90 degree sector patterns, 180 degree sector patterns, and figure eight patterns. The omni directional pattern (see Figure 1, below) is a general purpose pattern identical to the one emitted by simple antennas.
Figure 1. Phocus Array™ omni directional pattern
There are a variety of reasons to consider using a pattern other than an omni directional pattern. They fall into two general groups: extending the reach of the signal (making the signal strength as high as possible in a few directions) and reducing interference (minimizing the signal strength in the directions you do not want to cover). For technical reasons, the same pattern cannot effectively do both, so Fidelity Comtech optimizes some of its patterns primarily for reach and some primarily for interference mitigation.
The current pattern library contains two sets of directional patterns: the high gain directional patterns and the low side lobe directional patterns. The first is optimized for reach, the second for interference mitigation. Both patterns have a 43 degree beam width (from peak power in the center to half power on each side is 22.5 degrees). Graphics of these patterns can be seen below in Figure 2.
The pattern graphics in Figure 2 reveals that the high gain pattern has approximately 6 dB more gain (four times the power) in the direction it is pointed, and the low side lobe version has approximately 12 dB more rejection (less sensitivity by more than an order of magnitude). If the purpose of using the directional pattern is to maximize coverage in the direction the antenna is pointed, then the high gain pattern is appropriate. On the other hand, if the purpose is to avoid interference behind the antenna, then the low side lobe version is appropriate. Note that interference has two meanings – some source behind your antenna can be interfering with your antenna, or your antenna can be interfering with some one else operating behind it (likely another of your antennas).
Figure 2. High gain and low side lobe directional patterns
The directional patterns come in sets consisting of essentially the same pattern pointed in 16 different directions, each 22.5 degrees from the one before it. This allows the user to “point” the antenna in different directions without physically moving it. The black reference mark on the bottom of the Phocus Array™ System indicates the “North” direction (corresponding to the top of the graphic).
Figure 3. 90 degree and 180 degree sector patterns
The sector pattern sets (see Figure 3, above) are both optimized for interference mitigation. These patterns might be used on an antenna located in the corner of a yard (the 90 degree sectors) or an antenna located at the side of a yard (the 180 degree sectors). As with the directional patterns, the sector patterns come in sets of sixteen allowing the sector to be pointed without physically moving the antenna.
The figure eight patterns (see Figure 4, below) are intended for the situation where there is a long narrow area to be covered and the antenna is located in the center. There is approximately a 10 dB difference between the RSSI for the front and back and the RSSI for the sides. These patterns come in a set of eight to allow pointing.
Figure 4. Figure eight pattern
Installing A New Pattern Library
The Fidelity Comtech pattern library comes in two versions. The file “CommStd_11_10_421.tgz” is for Phocus Array™ Systems running version 2.1.x of the Phocus Array™ firmware. The file “CommStd_11_10_422.tgz” is for Phocus Array™ Systems running version 2.2.x of the Phocus Array™ firmware. Download the appropriate file to a computer that has access to the Phocus Array™.
Bring up the GUI for the Phocus Array™. Select the “Phocus Array” menu item then the “Upload Patterns” sub menu item (see Figure 5, below). Browse to the file you have downloaded then press the “Upload” button. After the patterns have loaded and the Phocus Array has rebooted (several minutes), select the “Phocus Array” menu item then the “Configure Antenna” sub menu item and use the drop-down menu to select the pattern you want. Pattern graphics can be viewed by selecting the “Phocus Array” menu item then the “Upload Patterns” sub menu item and clicking “Next” or “Previous” on the display.
Figure 5. Pattern Upload page
If you have any questions, please contact Fidelity Comtech technical support at 303-678-8245.