Antenna

An electrical device used to transmit or receive electromagnetic waves is called an antenna. They are used in systems such as radio and television broadcasting, radar and space exploration etc. It is basically an arrangement of conductors that generate a radiating electromagnetic field in response to an alternating voltage and the associated alternating electric current, or can be placed in the electromagnetic field so that the field will induce an alternating current in the antenna and a voltage between its terminals. There are two types of antennas, omni-directional antenna which radiates in all the direction of the plane and directional antenna which radiates more in one direction than the other. There are several parameters that affect an antenna's performance such as resonant frequency, impedance, gain, aperture, radiation pattern, polarization, efficiency and bandwidth. When people connect their PC's , entertainment systems or telephones they connect them either with the help of cables, wires, radio waves ( by using antenna), or by infrared light beams, Bluetooth and even greater variety of connectors, plugs and protocols. Bluetooth is an industrial specification for wireless personal area networks. It provides a way to connect and exchange information between devices such as PDA's, mobile phones, laptops etc. It is a radio standard and communications protocol primarily designed for low per consumption, with a short range (1 meter, 10 meter, and 100 meters) based around low-cost transceiver microchips in each device. The Bluetooth specifications were first developed by Sony Ericsson and were later formalized by Bluetooth Special Interest Group. There were different versions of Bluetooth; they have different enhancements e.g. Bluetooth version1.2 has major enhancements such as Adaptive Frequency-hopping spread spectrum, which improves resistance to radio frequency interference, higher transmission speeds, extended Synchronous Connections and Host controller interface.