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A wideband fractal slot antenna is proposed, designed, and fabricated in this communication. The broadband characteristic is achieved by introducing a Sierpinski fractal into a square wide slot without increasing the overall antenna size. A simple microstrip line is used to excite the Sierpinski-based slot. As the iteration order of the Sierpinski square radiator increases, the number of resonance increases, and the bandwidth of the slot antenna is enhanced. From the measured results, the 10 dB reflection coefficient bandwidth of the 2nd iteration Sierpinski slot antenna is 63.4%.

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Abstract-In this paper, a frequency reconfigurable antenna for cell-phone applications is presented. The proposed structure is based on a conventional PIFA. In addition, two stubs, each with a varactor diode, are incorporated. In order to achieve the wideband characteristic, the first two resonant frequencies (f 1 and f 2 ) of the proposed antenna are controlled independently by the supplied voltages with the variation of the capacitances. The equivalent circuit of the varactor diode has been extracted in order to accurately predict the performance of the proposed antenna. In addition, parametric studies regarding the capacitance and antenna length have been conducted. The measurement results show that the proposed antenna has a tunable bandwidth defined by a VSWR < 2.5 of 45.7%