The proposed paper presents a compact quad-band microstrip patch monopole antenna with a tunable capability. The proposed monopole antenna is formed by introducing the three C-shaped stubs of different lengths with a rectangular ring. The antenna uses an FR-4 substrate with a thickness of 0.5 mm. The proposed antenna is fed by a 50Ω CPW line and has a compact size of 20×21 mm 2 . The antenna operates at 2.58 GHz, 3.47 GHz, 3.66 GHz, and 4.07 GHz frequencies. The key parameters such as reflection coefficient, peak gain, and antenna radiation pattern are analyzed using ANSYS electronic desktop HFSS software.