A Frequency-Reconfigurable Antenna With 1-mm Nonground Portion for Metal-Frame and Full-Display Screen Handset Applications Using Mode Control Method

A frequency-reconfigurable antenna featuring four integrated switches for metal-frame and full-display screen handset applications is proposed in this paper. To achieve full-display aesthetics, the nonground portion of the proposed antenna is reduced to only 1 mm, making it impossible to formulate additional parasitic strips to enhance the bandwidth and radiation efficiency of the antenna. Four switches are employed in conjunction with the devised antenna to excite five resonant modes using the mode control method (MCM) to operate from 699 to 960 MHz and from 1710 to 2690 MHz. The proposed antenna is designed by employing several peripheral metallic components, such as steel sheet, USB, speaker box, and full-display screen into consideration, which enables the overall structure to be much closer to a practical smartphone environment. A prototype was fabricated and measured. The experimental results confirm that the proposed antenna features radiation efficiency from 30% to 55% for metal-frame and full-display screen handset applications.