Small-size antenna for seven-band WWAN/LTE mobile handset

Abstract

In this article, a small-size seven band antenna covering GSM850/900/1800/1900/ UMTS2100/LTE2300/2500 bands for WWAN/LTE mobile handset is presented. The developed antenna only occupies a planar size of 15×25mm2. The capacitive coupling feed is used to generate fundamental resonant λ/8 mode and high-order λ/4 mode to reduce the size. EM coupling between the radiation strips is used to widen the operation band. The antenna consists of a feed strip and two radiation strips(RS1, RS2). RS2 is in the same side of the ground. RS1 is in the other side of substrate. Two λ/8 modes(at 850 and 925MHz) and two λ/4 modes(at 1850 and 2200 MHz) are generated by the capacitive feed. Strip RS1 contributes to 850 and 1850 MHz modes, and strip RS2 contributes to 925 and 2200MHz modes. In the mean time, there exists electromagnetic(EM) coupling between the two radiation strips (RS1, RS2), then dual-resonance mode at 845 and 925 MHz form a wide lower band covering GSM850/900, two high order resonant modes at 1850 and 2200MHz form a wide upper band covering GSM1800/1900/UMTS2100/LTE2300/2500. Design mechanics is analyzed and main parameters are studied. The proposed antenna is fabricated, and the simulated and measured results agree well.