That is what Airgain has done. The company’s patented beam switching antenna can greatly improve the performance of some wireless applications. Their MaxBeam 75, shown in Figure 1, is designed for use in Wi-Fi APs, routers, and gateways used in enterprise and home networks. Airgain CEO Pertti Visuri explained the antenna this way: If you look closely, you will see four unusually-shaped monopole antennas at each corner of a ground plane. In the center is an X-shaped passive reflector for the antennas that provides the gain and directionality. All of the antenna elements are fed by transmission lines and matching circuits that tie together back to the single 50-ohm input/output connector. PIN diodes connected to each antenna switch each antenna off or on. By turning on two adjacent antennas at a time, it is possible to create eight beams over a 360° range. Turning on a third beam in some positions creates a total of 10 beams. The final result is an antenna that produces as much as a 300% increase in performance over that of a conventional dipole. Typical gain is 7 to 7.5 dBi.
The MaxBeam 75 is only 90 mm square, so it can fit inside most AP housings. And it is fully compatible with any 802.11b/g AP. The beam switching software runs on the host processor in the AP and the control signals are sent to the PIN diodes over a 6-wire cable. The software makes the decisions about what antennas to turn off and on to zero in on the signal for the best transmission and reception.
Airgain makes a number of other antennas that use the same beam switching techniques. Their MaxBeam65N incorporates MIMO, so it is compatible with the forthcoming 801.11n standard. A version called MaxBeam80N also uses MIMO. It covers the 5.7-5.9 GHz range, in addition to the 2.4 -2.49 GHz band. The H Smart antenna is designed for CardBus wireless products. And their MaxBeam 30 is a collinear array that can replace dipoles in some Wi-Fi and ISM band products.
For more information about Airgain’s smart antennas, visit airgain.com.
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