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An antenna is a device that couples currents to electromagnetic waves for purposes of radiation or reception. The process by which antennas radiate can be easily understood in terms of the way in which accelerating charged particles or time-varying currents radiate, which is discussed in Section 10.1.
Before we can design an antenna or discuss antenna types, we must understand the basics of antennas, which are the fundamental parameters that characterize an antenna. So let us learn something. We'll start with frequency and step through radiation patterns, directivity and gain, and ultimately close with an explanation on why antennas radiate.
The dipole antenna is symmetric when viewed azimuthally (around the long axis of the dipole); as a result the radiation pattern is not a function of the azimuthal angle . Hence, the dipole antenna is an example of an omnidirectional antenna.
25 paź 2024 · In radio communications, the length of an antenna is closely related to the frequency of the signal it is designed to transmit or receive. The general rule is that the higher the frequency, the shorter the wavelength, and as a result, the required antenna length decreases.
ANTENNAS. Antennas couple propagating electromagnetic waves to and from circuits and devices, typically using wires (treated in Section 3.2) or apertures (treated in Section 3.3).
1. Definition of the Antenna and Wave-Motion The radio antenna may be defined as the interface between a circuit in which electrical power is constrained to follow conducting paths, and electromagnetic radiation travelling freely through space. The antenna may convert power in the circuit into radiated energy or vice versa, forming either
An intuitive tutorial of antennas and antenna theory. This website is designed to present a comprehensive overview of antennas, from design, to measurement and theory. Unnecessarily complicated math is avoided throughout.
