A novel planar dual-band antenna by using a panel of photovoltaic cells as a metamaterial layer for dual-band operation is presented. A 10-Watt, 72-cell unmodified commercial photovoltaic panel is applied as a transparent layer in the first operation band and as a semi-transparent layer for λ/2 Fabry-Pérot cavity in the second operation band to achieve high antenna gain. Unit-cell transmission analysis is adopted to determine the frequency point of operation. The proposed prototype achieves remarkable 17.3 dBi and 6.6 dBi antenna gain at 3.5 GHz and 1.23 GHz, respectively fed by a dual-band dipole. With the aid of PV panel, the antenna can support an upper band at about 3550 MHz to cover the WiMAX 3.5 GHz (3400–3600 MHz) operation band and a lower band at about 1185 MHz to cover the 70 MHz operation bandwidth. The very combination of photovoltaic cell and antenna exhibits high fill factor, high-gain, and simple construction characteristics.