A Reconfigurable Antenna for Quad-Band Mobile Handset Applications

A reconfigurable antenna using two PIN diodes is presented for quad-band (GSM900/GSM1800/GSM1900/UMTS) mobile handset applications. The proposed antenna has a size of 45 × 11×6mm³. By independently adjusting the on/off states of the two PIN diodes located on the radiating element, the proposed structure can be operated in the PIFA and loop mode, respectively. The PIN diodes are replaced by conducting tape in order to verify the concept. In regards to the fabricated reconfigurable antenna, when operating in the PIFA mode, the measured results show that the 7 dB bandwidth is 8.62%, which covers the GSM900 (880 ~ 960 MHz) band. When operating in the loop mode, the measured results show that the 7 dB bandwidth is 26.36%, which covers the GSM1800 (1710 ~ 1880 MHz), GSM1900 (1850 ~ 1990 MHz), and UMTS (1920 ~ 2170 MHz) bands, respectively. The measured 3D average gains are -4.66 dBi ~ -3.8 dBi , -2.99 dBi ~ -1.81 dBi, -1.98 dBi ~ -1.75 dBi, and -2.31 dBi ~ -1.75 dBi for the GSM900, GSM1800, GSM1900 and UMTS bands, respectively.