Small‐size adjustable LTE/WWAN coupled‐fed loop antenna for mobile handset applications

Abstract

ABSTRACTA compact reconfigurable coupled‐fed loop antenna of the mobile handset for multiband long‐term evolution (LTE)/wireless wide area network operation is presented. The antenna volume is 5 × 10 × 30 mm3 only, while the protruded ground has a width of 30 mm for mounting electronic components. The proposed antenna is consisted of a loop strip and a driven strip. Through the driven strip capacitively coupled to the loop strip, the antenna can generate a 0.25‐wavelength loop resonant mode to form the antenna's lower band to cover the GSM850/900 bands (824–960 MHz). The simple driven strip is also an efficient radiator to excite a resonant mode for the antenna's upper band to cover the GSM1800/1900/WCDMA Band1 bands (1710–2170 MHz). Moreover, when the chip inductor connected to the loop strip has been adjusted from 0 to 12 nH, the antenna's lower band can be shifted to lower frequency and cover the LTE Band17 band (704–746 MHz) and the antenna's upper band is not varied. This tunable technique can allow the loop antenna to cover more operating bands without adding the antenna volume. Detailed operating principle and performances of the proposed antenna are discussed in this article. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2687–2691, 2014