What is Vivaldi Antenna?

What is Vivaldi Antenna?

Vivaldi antenna is a broadband antenna, also known as Vivaldi aerial and tapered slot antenna. Vivaldi antenna was invented by Peter Gibson in 1978. It can be made using a solid piece of sheet metal or printed circuit board. The illustration shows a Vivladi antenna made from double sided printed circuit board material. A single Vivaldi antenna transmits linearly polarized electromagnetic waves. If two antennas placed orthogonally are fed 90 degree phase shifted signals they can generate circularly polarized electromagnetic waves similar to cross Yagi used in satellite communications. Vivaldi antennas are typically made on printed circuit boards cost effectively for microwave frequencies of 1 GHz and above. It has been mentioned that the antenna was named after Antonio Vivaldi a 17th century Italian composer, in the year of his 300th birth anniversary. You may note that the tapered slot of the Vivaldi antenna resembles a trumpet and Vivaldi had written a trumpet concerto. Peter Gibson the inventor of Vivaldi antenna, had a great interest in music!

This is the picture of an inexpensive Vivaldi antenna etched upon a printed circuit board and fed with a soldered-on coaxial cable and SMA connector, from Wikipedia. When the Vivaldi antenna is excited by a radiofrequency current, electromagnetic waves radiate from the tapered slot. Though it is a broadband antenna, its lower frequency is limited by the width of the gap and upper frequency limit by the size of the opening. The name tapered slot antenna is because its radiating elements taper outwards from the slot line. Shape and size of the slot determines the antenna’s radiation pattern. I read up Vivaldi antenna when a couple of hams on QRZ posted pictures of Vivaldi antennas which they use, in response to my earlier post on Frequency Independent Antennas. One of them at WA5VJB.com has a frequency range from 1.5 GHz to 15 GHz! Such antennas have been called Ultra Wide Band (UWB) antennas.