Parallel Dual-Loop Antenna for WWAN/LTE Metal-Rimmed Smartphone

A simple internal antenna design for wireless wide-area network/long-term evolution (LTE) operations is investigated, and it can be incorporated into a mobile phone that has an unbroken metal rim of height 5 mm. The proposed antenna is mainly composed of two parallel slots (dual loop) embedded on the system ground, and by feeding them with an L-shaped coupled feedline with matching networks, good excitation of multiple loop resonant modes can be obtained, which is capable of covering the GSM850/900 (824–960 MHz), DCS/PCS/UMTS2100, and LTE2300/2500 (1710–2690 MHz) operating bands. In addition, the feasibility of realizing decoupled multiantennas ( $2 \times 2$ multi-in multi-out antenna system) is also demonstrated, and its performances are acceptable for smartphone applications.