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A Vivaldi antenna or Vivaldi aerial or tapered slot antenna is a co-planar broadband- antenna, which can be made from a solid piece of sheet metal, a printed circuit board, or from a 
Vivaldi antennas can be made for linear polarized waves or – using two devices arranged in orthogonal direction – for transmitting / receiving both polarization orientations.
If fed with 90° phase-shifted signals, orthogonal devices can transmit/receive 
Advantages of Vivaldi antennas are their broadband characteristics (suitable for
dielectric
In electromagnetism, a dielectric (or dielectric medium) is an electrical insulator that can be polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the mate ...
plate metalized on one or both sides.
The feedline
In a radio antenna (radio), antenna, the feed line (feedline), or feeder, is the cable or other transmission line that connects the antenna with the radio transmitter or Radio receiver, receiver. In a transmitting antenna, it feeds the radio ...
excites an open space via a microstrip line
Microstrip is a type of electrical transmission line which can be fabricated with any technology where a conductor is separated from a ground plane by a dielectric layer known as the substrate. Microstrip lines are used to convey microwave-freque ...
or coaxial cable, and may be terminated with either a sector
Sector may refer to:
Places
* Sector, West Virginia, U.S.
Geometry
* Circular sector, the portion of a disc enclosed by two radii and a circular arc
* Hyperbolic sector, a region enclosed by two radii and a hyperbolic arc
* Spherical sector, a p ...
-shaped area or a direct coaxial connection. From the open space, the signal traverses an exponentially tapered pattern via a symmetrical slot line.
Vivaldi antennas can be made for linear polarized waves or – using two devices arranged in orthogonal direction – for transmitting / receiving both polarization orientations.
If fed with 90° phase-shifted signals, orthogonal devices can transmit/receive circular
Circular may refer to:
* The shape of a circle
* ''Circular'' (album), a 2006 album by Spanish singer Vega
* Circular letter (disambiguation)
** Flyer (pamphlet), a form of advertisement
* Circular reasoning, a type of logical fallacy
* Circular ...
-oriented electromagnetic wave
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visib ...
s.
Vivaldi antennas are useful for any frequency, as all antennas are scalable in size for use at any wavelength. Printed circuit technology makes this type antenna cost effective for microwave
Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ra ...
frequencies 1 GHz or higher.
Advantages of Vivaldi antennas are their broadband characteristics (suitable for ultra-wideband
Ultra-wideband (UWB, ultra wideband, ultra-wide band and ultraband) is a radio technology that can use a very low energy level for short-range, high-bandwidth communications over a large portion of the radio spectrum. UWB has traditional applicati ...
signals ), their easy manufacturing process using common methods for PCB
PCB may refer to:
Science and technology
* Polychlorinated biphenyl, an organic chlorine compound, now recognized as an environmental toxin and classified as a persistent organic pollutant
* Printed circuit board, a board used in electronics
* ...
production, and their easy impedance matching
In electronics, impedance matching is the practice of designing or adjusting the input impedance or output impedance of an electrical device for a desired value. Often, the desired value is selected to maximize power transfer or minimize si ...
to the feeding line using microstrip line
Microstrip is a type of electrical transmission line which can be fabricated with any technology where a conductor is separated from a ground plane by a dielectric layer known as the substrate. Microstrip lines are used to convey microwave-freque ...
modeling methods.
The MWEE collection of EM simulation benchmarks includes a Vivaldi antenna.
Several researchers have experimented variations in the shape of the Vivaldi antenna to improve some of its characteristics. An example is the Palm Tree Vivaldi Antenna, with greater gain and directivity, used in Near-Field Microwave Biomedical Imaging Applications.
References
{{radio-stub Radio frequency antenna types