Smart Antennas (Repost)

Smart antennas involve processing of signals induced on an array of sensors such as antennas, microphones, and hydrophones. They have applications in the areas of radar, sonar, medical imaging, and communications. Smart antennas have the property of spatial filtering, which makes it possible to receive energy from a particular direction while simultaneously blocking it from another direction. This property makes smart antennas a very effective tool in detecting and locating an underwater source of sound such as a submarine without using active sonar. The capacity of smart antennas to direct transmitting energy toward a desired direction makes them useful for medical diagnostic purposes. This characteristic also makes them very useful in canceling an unwanted jamming signal. In a communications system, an unwanted jamming signal is produced by a transmitter in a direction other than the direction of the desired signal. For a medical doctor trying to listen to the sound of a pregnant mother’s heart, the jamming signal is the sound of the baby’s heart.