A slot dipole antenna capable of triple band operation is presented. The antenna configuration is consists of three parallel pairs of thin slots, where each pairs of slot generate a single band. By placing variable capacitors at the specific location on the each arm pairs, the operating frequency of the antenna can be tuned over a wide range. Depending on the capacitor values, the operating frequency can be tuned from 2.0 GHz to 5.3 GHz. The proposed antenna is designed to suit the future multi-mode applications such as cognitive radio systems. The analyses of the antenna were based on the return loss, surface current distribution, and radiation pattern with gain performance will be discussed.