What is a Vivaldi antenna?
A Vivaldi antenna is a printed endfire tapered-slot antenna whose slot widens exponentially from a narrow feed region to a wide mouth. Described by P. J. Gibson in 1979,[1] it offers multi-octave bandwidth, moderate gain (typically several to over 10 dBi) and linear polarization, and is widely used in UWB systems, wideband phased arrays and measurement.[2][3]
How does a Vivaldi work?
Waves travel along the slotline and are progressively released where the slot width reaches about half a wavelength, so different frequencies radiate from different parts of the taper. The lowest frequency is set approximately by the mouth width (around λ/2) and the antenna length.[1][3]
How is it fed?
A microstrip-to-slotline transition with radial stubs or a cavity provides a broadband balun. The antipodal Vivaldi places the two flares on opposite sides of the substrate, fed directly by microstrip transitioning to parallel strips.[3]
Why are Vivaldis used in arrays?
Closely spaced Vivaldi elements form “tapered-slot” or notch arrays with wide scan and bandwidth; mutual coupling actually helps broadband behavior in such arrays, though scan blindness must be managed.[4]
Frequently asked questions
Is a Vivaldi directional?
Yes, endfire along the taper axis.
What is a typical bandwidth?
Multi-octave; 10:1 is commonly reported.
Does it have a stable phase center?
It moves with frequency, a consideration for UWB pulse fidelity.
See also
References
Online sources accessed October 21, 2026; printed works cited by edition. See all sources.
- “The Vivaldi Aerial”. P. J. Gibson, Proceedings of the 9th European Microwave Conference, pp. 101-105. 1979.
- “The Art and Science of Ultrawideband Antennas”. H. G. Schantz, Artech House. 2005.
- “Antenna Engineering Handbook, 4th ed.”. J. L. Volakis (ed.), McGraw-Hill. 2007.
- “Phased Array Antenna Handbook, 3rd ed.”. R. J. Mailloux, Artech House. 2017.