Vivaldi Antenna

A Vivaldi 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 dielectric plate metalized on one or both sides.

A one-piece sheet metal vivaldi antenna undergoing testing in an anechoic chamber

Vivaldi antennas are useful for any frequency, as all antennas are scalable in size for use at any frequency. Printed circuit technology makes this type antenna cost effective at microwave frequencies exceeding 1 GHz.

FT-RF Vivaldi Antenna uses for 700MHz to 10GHz frequency.

Source: Wikipedia