This chapter reviews ultra wideband (UWB) planar spoof surface plasmon polaritons (SSPP) antennas that operate in microwave to millimeter-wave bands. The techniques used to determine the UWB properties of SSPP-based antennas and their performance in various operating bands have been carefully analyzed and compared. Leaky-wave and end-fire antennas are the two types into which they are categorized. The pros and cons of various antenna design structures, sizes, radiation types, beam scanning capacities, bandwidths, and gains are evaluated. Most of the studies used gradient grooved transitions to SSPP mode and a variety of slots to achieve bandwidths of 100% or more. The end-fire antennas exhibit high efficiency, ranging from 75–98%, with an average gain change of about 5 dBi. On the other hand, the leaky-wave antennas present a total wide beam-scanning range of 90° to 142°, a high efficiency of 70–98%, and a low gain variation of about 3 dBi. The purpose of this paper is to serve as a reference for future research by emphasizing the most significant characteristics of the SSPP-based UWB antennas that are currently being investigated for potential use in the next generation of applications.