An antenna is a critical device used to radiate or receive electromagnetic energy efficiently in desired directions. This tutorial outlines core operational properties and reviews major classes of antennas, including dipoles, loops, apertures, reflectors, and arrays.
Antennas act as matching systems between sources of electromagnetic energy and free space. The primary goal in antenna design is to optimize this energy transfer. All antennas are reciprocal and can be used interchangeably to transmit or receive energy.
Depending on application requirements, frequency bands, and physical constraints, antennas are grouped into several standard configurations:
One of the most common configurations consisting of a straight conductor excited by a voltage from a transmission line or waveguide. They are simple to construct.

Configured using a loop of wire with single or multiple turns, utilized effectively for specialized radiation and reception applications.

Horn antennas are typical examples of aperture antennas. These robust systems are heavily utilized in aircraft and aerospace communication systems.

Parabolic reflectors excel at microwave frequencies. Historically common in space tech, they are now ubiquitous globally for satellite television reception.

Formed by grouping similar or distinct individual radiator elements together. Controlling the relative phase shift element-by-element allows electronic scanning of the radiation beam direction (beamforming).
