Multi-band reconfigurable antenna for mobile handset applications

In this study, a novel reconfigurable antenna using a PIN diode is proposed for multiband (GSM900/1800/1900/UMTS/LTE2300/2500) operation in mobile handsets. By adjusting the on/off state of the PIN diode, the reconfigurable antenna operates in a planar inverted-F antenna (PIFA) mode as well as a loop mode. The operating bandwidth at a low band is attributed to the PIFA mode. The broad bandwidth at a high band is easily achieved in the PIFA mode as well as the loop mode. It is observed from the measured results that this planar antenna exhibits an impedance bandwidth of ~8.7% at the 920-MHz band and ~48.3% at the 2250-MHz band. With the reconfigurable technology, the antenna can achieve a compact size of 27 × 10 × 1.6 mm³.