Vivaldi-antenna

The Vivaldi antenna, also tapered slot antenna abbreviated TSA is a broad-band antenna for the microwave range, consisting of a co-planar structure on a double-sided metallized dielectric substrate. The name goes back to PJ Gibson, which this antenna design in 1979 at the IEEE European Microwave Conference first described.

Operation

Vivaldi antennas are fed by a slot line. If the matching unit present in microstrip technology, a transition is necessary. This can be realized in a relatively broad band when the strip line is terminated with a sector-shaped surface element. A current node is realized at the crossing point. The slot-line, however, is also terminated with a broadband circular space, which is a quarter wavelength long. The actual antenna is a two-dimensional exponential horn, which causes the directed emission of a linearly polarized electromagnetic wave. Overall, a low-reflection transformation of the wave impedance of the strip line is at the different free-space wave resistance.

Vivaldi antennas can be used for linear polarization, or - be established for both polarization directions - when two antennas are perpendicular to each other.

When the two orthogonal antennas are fed with a phase shifted by 90 ° signal, a circularly polarized wave is radiated or received. Generating a wideband constant phase shift of 90 ° is, however, difficult to realize.

The advantage of Vivaldi antennas is their simple preparation, the PCB manufacturing can be used in the conventional methods, as well as its wide bandwidth and ease of adaptation to the feed line impedance using the modeling of the stripline feed structure.

The Vivaldi antenna can be considered as planar shape of a ridge horn.