As communication systems demand compact size and multi-functionality, advanced antenna elements with radiative feature including frequency-tunability, multi-band functionality, and polarization-flexibility are highly sought after. This paper presents a novel antenna structure delivering abovementioned desirable features. The antenna is fabricated on a single printed circuit board and tuned using varactors. The simulated results correspond well with the measured results. The proposed antenna shows frequency tuning range from 1.54 GHz to 2 GHz at first radiation band. Second radiation appears at around 5.3 GHz. The antenna has a very compact size of around 0.1\ {\lambda_{\mathrm{g}}}^{2}$ and 0.7\ {\lambda_{\mathrm{g}}}^{2}$ at first and second radiation frequencies, respectively.