WiMAX Antennas

Figure 11: Different antenna types are designed for different applications

WiMAX antennas, just like the antennas for car radio, cell phone, FM radio, or TV, are designed to optimize performance for a given application. The figure above illustrates the three main types of antennas used in WiMAX deployments. From top to bottom are an omni directional, sector and panel antenna each has a specific function.

Omni directional antenna


Figure 12: An omni-directional antenna broadcasts 360 degrees from the base station

Omni directional antennas are used for point-to-multipoint configurations. The main drawback to an omni directional antenna is that its energy is greatly diffused in broad-casting 360 degrees. This limits its range and ultimately signal strength. Omni directional antennas are good for situations where there are a lot of subscribers located very close to the base station. An example of omni directional application is a WiFi hotspot where the range is less than 100 meters and subscribers are concentrated in a small area.


Sector antennas



Figure 13: Sector antennas are focused on smaller sectors

A sector antenna, by focusing the beam in a more focused area, offers greater range and throughput with less energy. Many operators will use sector antennas to cover a 360-degree service area rather than use an omni directional antenna due to the superior per-formance of sector antennas over an omni directional antenna.


Panel antennas



Figure 14: Panel antennas are most often used for point-to-point applications

Panel antennas are usually a flat panel of about one foot square. They can also be a configuration where potentially the WiMAX radio is contained in the square antenna enclosure. Such configurations are powered via the Ethernet cable that connects the ra-dio/antenna combination to the wider network. That power source is known as Power over Ethernet (PoE). This streamlines deployments as there is no need to house the radio in a separate, weatherproof enclosure if outdoors or in a wiring closet if indoors. This configuration can also be very handy for relays. 

Jose Galviz

http://www.wimax.com/education/wimax/antennas

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