A Microstrip Square-Ring Slot Antenna (MSRSA) for UWB (Ultra WideBand) antenna applications is proposed and improved by compaction. This structure is fed by a single microstrip line with a fork like-tuning stub. By splitting the Square-Ring Slot Antenna (SRSA) and optimization of the feeding network, the required impedance bandwidth is achieved over the UWB frequency range (3.1 to 10.6GHz). The experimental and simulation results exhibit good agreement together. Parametric study is applied to compaction of structure. This compaction provides a good radiation pattern and a relatively constant gain over the entire band of frequency.