Low-Profile Compact Antenna for Octa-Band Metal-Rimmed Mobile Phone Applications

In this article, a compact low-profile antenna for octa-band unbroken metal-rimmed smartphone applications is proposed. The antenna consists of a capacitive coupling rectangular vertical plate and two new-type extended ground branches. For lower frequency, the LTE700, GSM850, and GSM900 bands are provided by the bezel mode which is generated through capacitive coupling excitation of a rectangular vertical plate to the bezel. For upper frequency, the DCS, PCS, UMTS, LTE2300 and LTE2500 bands are covered by the multiple modes of two ground branches. With the proposed structure, the operating bands can be expanded and optimized simply. All the mentioned bands are achieved in the size of (70 × 7 + 20 × 2) × (1.5 + 0.8) mm
³
on the 130 mm × 70 mm system board. The antenna is fabricated and measured to verify this proposal. The tested results include reflection coefficient, radiation patterns, efficiency, and gain.