Reconfigurable PIFA with a parasitic strip line for a hepta-band WWAN/LTE mobile handset

In this study, a reconfigurable planar inverted-F antenna (PIFA) with a parasitic strip line for a hepta-band wireless wide area network (WWAN)/long term evolution (LTE) mobile handset is proposed. The PIN diode is located between the end of the parasitic strip line and the protruded ground plane. Depending on the on/off-state of the PIN diode, the degree of coupling between the conventional PIFA and the parasitic line is controlled and the fundamental resonant frequency of the proposed antenna is adjusted. As a result, the fundamental resonant frequencies cover the (global system for mobile communication) GSM850 (824-894 MHz) and GSM900 (880-960 MHz) bands. By the parasitic strip line extended from the protruded ground plane, impedance matching at the higher-order modes (f₂ and f₃) is improved and the fourth resonant frequency f₄ is remarkably decreased. The high band of the antenna is formed by combining these three higher-order modes to cover the GSM1800 (1710-1880 MHz), GSM1900 (1850-1990 MHz), universal mobile telecommunication system (UMTS) (1920-2170 MHz), LTE2300 (2305-2400 MHz) and LTE2500 (2500-2690 MHz) bands.