Coupled-Fed Antenna with Parasitic Ground Structure for Octa-band WWAN/LTE Narrow-Frame Mobile Phone

In this work, an octa-band narrow-frame mobile phone antenna with the size of 80×7×5.5 mm3 is proposed and studied. The designed antenna adopts coupled-fed technology, which is mainly composed of an F-shaped feeding strip, a coupled bending shorted strip, an upright copper plate and a parasitic ground structure. By introducing the F-shaped feeding strip, the coupled bending shorted strip and the upright copper plate, the working frequency of the antenna can cover the lower band (LTE700/GSM850/GSM900) and part of the upper band. Then, with further use of the parasitic ground structure, the upper band (DCS1800/PCS1900/UMTS2100/LTE2300/LTE2500) can be successfully covered in the proposed antenna. Moreover, in this antenna the non-ground portion height is only 7 mm, showing a fully coverage of 2G/3G/4G operating bands without any matching circuit, and great potential for applications in mobile wireless communication systems. In addition, a prototype of the proposed antenna is fabricated and characterized. From the experimental results, the measured -6 dB impedance bandwidths of the antenna at the lower and upper bands are 305 MHz (660-965 MHz) and 1290 MHz (1630-2920 MHz), respectively. Meanwhile, this antenna shows good radiation characteristics in the operating bands.