Nowadays, several interesting antenna structures are proposed. However, monopole antenna still presents major interest to many authors. This paper proposes a new compact multi-wideband monopole antenna for wireless communication (5G), medical, and radar applications. The miniaturized antenna is printed on an FR4 substrate and fed by a 50 Ω microstrip line, the resulting antenna has a size of 18 × 15.5 × 1.6 mm. A parametric study was performed to improve the performance of our proposed antenna, S11, gain and radiation patterns, are investigated in detail. The steps of the parametric study and the results obtained from the miniaturized antenna are discussed. The results show that the proposed antenna is well used for different applications. The proposed antenna was simulated and optimized by HFSS software. Firstly, the simulation results show that the proposed design is verified by good resonance frequencies for 5G, medical, and radars (satellite) applications.