Reconfigurable 3-D slot antenna design for 4G and sub-6G smartphones with metallic casing

Abstract

The design of a reconfigurable three-dimensional (3-D) slot antenna for 4G and sub-6G smartphone application is presented in this paper. The antenna is located at the bottom of the smartphone and integrated with a metallic casing. Positive-Intrinsic-Negative (PIN) diodes are loaded at the dual-open slot and the folded U-shaped slot, respectively, which are used to realize four working states. The antenna has a compact volume of 42 × 6 × 6 mm3, which can cover the long term evolution (LTE) bands of 698-960 MHz and 1710-2690 MHz, and the sub-6G bands of 3300-3600 MHz & 4800-5000 MHz. The design processes are presented and the structure is optimized, fabricated and measured. The comparison to other state-of-the-art antennas shows that the proposed design has multiband characteristics with small size.