Antennas are devices that transmit and receive electromagnetic waves, commonly used in communication systems. They convert electrical signals into radio waves and vice versa, enabling wireless communication for devices like radios, televisions, and mobile phones. Antennas come in various shapes and sizes, each designed for specific frequencies and applications. The effectiveness of an antenna depends on its design, which can include elements like dipoles, loops, and parabolic dishes. Proper placement and orientation are also crucial for optimal performance, as they can significantly affect signal strength and quality. Understanding antennas is essential for improving communication technologies.