INTERNAL EIGHT-BAND WWAN/LTE HANDSET ANTENNA USING LOOP SHORTING STRIP AND CHIP-CAPACITOR-LOADED FEEDING STRIP FOR BANDWIDTH ENHANCEMENT

摘要

A planar inverted-F antenna (PIFA) with a loop shorting strip and a chip-capacitor-loaded feeding strip to achieve a small size yet wideband operation for eight-band WWAN/LTE operation (698960/17102690 MHz) in the mobile handset is presented. The antenna occupies a small no-ground footprint of 15 × 35 mm~2 on the main circuit board of the handset and is closely integrated with the surrounding system ground plane to achieve compact integration inside the handset. By applying the proposed shorting strip and feeding strip, a dual-resonance excitation at about 800 MHz which forms the antenna's wide lower band to cover the LTE700/GSM850/900 operation is obtained. Further, the proposed shorting strip and feeding strip lead to the generation of additional higher-order resonant modes to assist in forming a wide upper band for the antenna to cover the GSM1800/1900/UMTS/LTE2300/2500 operation. The proposed antenna also shows good radiation characteristics over the eight operating bands. The obtained SAR values of the antenna are well less than the limit of 1.6 W/kg for 1-g head tissue for practical handset applications.