Any microstrip antenna achieving wideband characteristics similar to Vivaldi antenna?

I have recently learned about Vivaldi antennas, which can be realized in microstrip technology. Does anybody aware of antennas with similar wideband characteristics that can be realized in microstrip technology?

I want to share my thoughts on Vivaldi antennas. With recent developments in SIWs (substrate integrated waveguides) such antennas become really attractive, because planar Vivaldi antenna can be fed using SIW, whole design can be made easy using only one layer two-sided PCB. Compared to complicated multi-layer designs of stacked patches and slot fed patches it is easier to design. I think it is good alternative for WiFi and similar antennas (patch arrays) because planar array of few Vivaldi elements forms narrow E-plane beam, beam shape and excellent gain can be maintained for several bands, antenna have low requirements to dielectric constant tolerances (FR4), i guess it can fit in same enclosure as traditional patch arrays for WiFi, though it must be positioned differently. Maybe a little bigger.

The are lots of examples of such antennas. Too many to list here. Run the following Google searches and click on images.

Google:- UWB Antenna; uwb cpw antenna ; uwb monopole antenna

Lots are can be seen as variants of the Vivaldi, but with 2 exponential slots that go off at plus and minus 90° to create a more omni pattern. e.g. the antennas with 2 circles places above and below each other, or a circle above a flat ground plane. Many of these use Co-Planar Waveguide(CPW) as a convenient feed. Beyond that there are many variations that aim to tailor the frequency responses, gain patterns etc for specific requirements.

I definitely see these as being more useful as we move to higher GHz radio systems in the future as transmission line losses mean they need to be closely located with the silicon, hence being integrated into the same substrate makes a lot of sense. And as the frequencies go up, the size implications on the substrate reduce. I don't know if current generation WiFi benefits too greatly from this as the antenna bandwidths can readily be supported by simple dipoles and patches in a smaller volume, and the frequency selectivity of these reduces the need for electronics filtering.

true, i did not considered that. It may be a problem in some application.