As an antenna achieves gain and propagates in certain directions, it will propagate less in other directions. This is because the power being fed into the antenna does not change; the power output of the radio driving the antenna is always constant. A phased array antenna does not change the power output, only the direction in which the power is sent (in the form of radio waves). As the gain on a phased array antenna increases, so does the directionality of the antenna.
Compared to omni-directional antenna solutions, the VT2210 Outdoor Base Station can cover over 10 times the range and up to 25 times the coverage area with its beamforming phased array antenna design and Packet Steeringª technology. Vivato base stations uniquely utilize 6 Wi-Fi radios operating at 200 mw each, which are coupled to a passive 8x8 slot phased array antenna with 23dbi gain. To be clear, the 200 mw Wi-Fi radio is applied to the passive antenna with no additional injected power.
A slot array antenna simply focuses each radio's beam more accurately. The beam tracks the client across 6 pointing directions, one for each radio, across the 90 degree span, to optimize the communications path to the client. Using the patented Packet Steering Technology each antenna beam is very narrowly focused delivering a beam pattern, which is 15 degrees horizontal by 12 degrees vertical, limiting the amount of extraneous RF noise. The EIRP from multiple channels will not be cumulative because each radio is aimed in a different direction and each radio operates independently and coordinated to produce a "Virtual Point-to-Point" mode of operation.
The Access Point constantly monitors the 6 radios for inbound client transmissions to determine the best path and then associates the client to a particular WLAN interface. This information is utilized by the Base Station to determine which WLAN interface to use to send traffic. To the client, the VP2210 Base Station appears as 6 individual WLANs. The client can roam across these WLANs just as it would roam across coverage cells provided by 6 separate APs in a typical WLAN environment.
EIRP is used to measure the effective power rating based on the theoretical isotropic model, the RF transmissions pattern for Vivato is within a narrow RF energy lobe extending from the phased array antenna in the direction of one of the 6 sectors. Omni-directional transmissions send RF energy in all directions, more realistically within a donut shaped pattern emanating from the antenna. The Vivato system more effectively delivers the RF energy to the intended target and decreases the contributed noise in the 2.4GHz spectrum when compared to omni or sectorized antenna transmissions.
The FCC's Part 15 rules allow for the use of Point-to-Point and Point-to-Multipoint deployments. The Point-to-Point regulations allow higher field strength than the Point-to-Multipoint rules. The Point-to-Point regulations, however, require that the power to the transmitter be reduced by an amount that depends on the transmitter antenna gain. Wi-Fi APs and client devices typically operate under the Point-to-Multipoint rules. Under these rules higher gain antennas can be added to these devices as long as the limit of 4W (Watts) EIRP is not exceeded. Typical client devices operate from 10mW to 100mW of transmitter power for battery life, safety and other considerations.
The Vivato Wi-Fi Base Station, on the other hand, is authorized and operated under Point-to-Point rules while servicing standard Wi-Fi clients. When designing the Wi-Fi Base Station, Vivato's engineers were able to achieve symmetric range improvements of 5 to 10 times that of standard APs with an antenna gain of 23dBi and transmitter power no greater than that found in a standard client resulting in an EIRP of 20W.
The combination of this extended range and the phased array's ability to electronically synthesize multiple high gain antennas covering a 90 degree field of view makes the Vivato Wi-Fi Base Station an ideal solution for the needs of a Wi-Fi WMAN deployment.