Ultra-wideband (UWB) systems because of unique characteristics including specific frequency spectrum allocated by the Federal Communication Committee (FCC) obtained many applications in modern communication technologies like industrial IOT, outdoor and indoor positioning, healthcare and biomedical, intelligent home electronics and so forth. UWB Antennas present unique challenges, particularly in achieving size reduction and bandwidth enhancement. This chapter addresses these challenges by exploring a variety of UWB antenna types, including planar monopole and slot antennas, and examines techniques for bandwidth enhancement and size reduction. Given the potential interference with narrowband systems such as WLAN, WiMAX, and X-band satellite downlink, the chapter also delves into band notching and filtering techniques. Furthermore, the chapter discusses UWB pulse characteristics essential for impulse radio applications and provides an in-depth analysis of indoor UWB propagation characteristics. Through case studies and practical examples, the chapter offers insights into real-world UWB antenna designs and provides a comprehensive understanding of the challenges and solutions associated with UWB systems.