_{Wireless Communications Industry Chair Professor of electrical and computer engineering at the University of California San Diego. Ph.D. - California Institute of Technology.}

An antenna is a device that is designed to transmit or receive electromagnetic waves. These waves are a type of energy that travels through the air and is used for various forms of communication, such as radio and television broadcasting, cell phone communication, and satellite communication.

The design of an antenna depends on the specific frequency of the electromagnetic waves it is intended to transmit or receive. Different frequencies require different types of antennas. For example, an antenna used for AM radio broadcasting will have a different design than an antenna used for satellite communication.

Antennas can be designed to be highly directional, focusing their energy in a specific direction, or they can be designed to be more omnidirectional, radiating energy in all directions. The specific design of an antenna is determined by the specific application for which it will be used.

In general, antennas are made up of a conductor, or wire, that is shaped in a specific way to transmit or receive electromagnetic waves. The shape and size of the conductor, as well as the materials it is made of, will affect the performance of the antenna. Antennas can be made from a variety of materials, including metal, plastic, and even wood.

The first antennas were built in 1888 by German physicist Heinrich Hertz in his pioneering experiments to prove the existence of waves predicted by the electromagnetic theory of James Clerk Maxwell. Hertz placed dipole antennas at the focal point of parabolic reflectors for both transmitting and receiving. Starting in 1895, Guglielmo Marconi began development of antennas practical for long-distance, wireless telegraphy, for which he received a Nobel Prize [1].

_{[1] Wikipedia}