radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...

and

telecommunication Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...

, a traveling-wave antenna is a class of

antenna Antenna ( antennas or antennae) may refer to: Science and engineering * Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves * Antennae Galaxies, the name of two collid ...

that uses a traveling wave on a guiding structure as the main radiating mechanism. Its distinguishing feature is that the radio-frequency current that generates the radio waves travels through the antenna in one direction. This is in contrast to a ''resonant antenna'', such as the monopole or

dipole In physics, a dipole () is an electromagnetic phenomenon which occurs in two ways: *An electric dipole deals with the separation of the positive and negative electric charges found in any electromagnetic system. A simple example of this system i ...

, in which the antenna acts as a

resonator A resonator is a device or system that exhibits resonance or resonant behavior. That is, it naturally oscillates with greater amplitude at some frequencies, called resonant frequencies, than at other frequencies. The oscillations in a resonator ...

, with radio currents traveling in both directions, bouncing back and forth between the ends of the antenna. An advantage of traveling wave antennas is that since they are nonresonant they often have a wider

bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...

than resonant antennas. Common types of traveling wave antenna are the

Beverage antenna The Beverage antenna or "wave antenna" is a long-wire receiving antenna mainly used in the low frequency and medium frequency radio bands, invented by Harold H. Beverage in 1921. It is used by amateur radio, shortwave listening, and longwav ...

, axial-mode

helical antenna A helical antenna is an antenna consisting of one or more conducting wires wound in the form of a helix. A helical antenna made of one helical wire, the most common type, is called ''monofilar'', while antennas with two or four wires in a ...

, and

rhombic antenna A rhombic antenna is made of four sections of wire suspended parallel to the ground in a diamond or "rhombus" shape. Each of the four sides is the same length – about a quarter-wavelength to one wavelength per section – converging but not to ...

. Traveling-wave antennas fall into two general categories: ''slow-wave antennas'', and ''fast-wave antennas''. Fast-wave antennas are often referred to as leaky wave antenna.

References

* C. H. Walter, ''Traveling Wave Antennas'', McGraw-Hill, 1965, Dover, 1970, reprinted by Peninsula Publishing, Los Altos, California, 1990. * T. Rozzi and M. Mongiardo, ''Open Electromagnetic Waveguides'', The Institution of Electrical Engineers(IEE), London, 1997. * M. J. Ablowitz and A. S. Fokas, ''Complex variables: Introduction and Applications'', second edition, Cambridge University Press, 2003. * A. A. Oliner and T. Tamir, "Guided complex wave, part I: field at an interface", Proc. IEE, Vol. 110, pp. 310-324, February 1963. * A. A. Oliner and T. Tamir, "Guided complex wave, part II: relation to radiation pattern", Proc. IEE, Vol. 110, pp. 325–334, February 1963. * A. Hessel, "General characteristics of traveling-wave antennas", Chapter 19 in Antenna Theory, R. E. Collin and F. J. Zucker, Editors, McGraw-Hill, New York, 1969. Antennas (radio)

See also

References