A Full Metal-Rimmed Antenna Using Capacitive Feed and Ground for LTE Mobile Handsets

In this letter, a full metal-rimmed antenna using a capacitive feed and ground is proposed and designed for LTE mobile handsets. The full metal rimmed antenna can be structurally represented by a loop antenna formed along the metal rim and PCB ground. The capacitive feed decreases the large reactance seen at the half wavelength mode for the loop antenna, which leads to excitation of the half wavelength mode for the loop antenna and reduces the length of the proposed antenna. In addition, a gap-coupled ground is employed to obtain additional resonance in the high band. To verify its feasibility and performance, we simulated and measured the characteristics of the proposed antenna, such as the reflection coefficient, total efficiency, and far-field radiation patterns. The overall dimension of the metal rimmed antenna is 75 mm x 10 mm (length x width), and the total efficiencies are measured more than 60% in the quad-band.