Small-size printed loop-type antenna integrated with two stacked coupled-fed shorted strip monopoles for eight-band LTE/GSM/UMTS operation in the mobile phone

Abstract

A small-size internal printed antenna formed by a loop-type antenna integrated with two stacked coupled-fed shorted strip monopoles is presented.The proposed antenna has a small uniplanar structure of 40 × 15 mm2 (600 mm2) for eight-band LTE/GSM/UMTS operation in the mobile phone. The loop-type antenna comprises a driven monopole and a coupled portion short-circuited to the system ground plane of the mobile phone; the driven monopole alone contributes a resonant mode for the antenna's upper band, whereas the driven monopole and shorted coupled portion together provide a loop-type resonant path to generate a resonant mode for the antenna's lower band. Two stacked strips are then integrated with the loop-type antenna, with the two strips coupled-fed by the driven monopole and short-circuited to the ground plane through the shorted coupled portion. That is, two stacked coupled-fed shorted strip monopoles are formed and incorporated with the loop-type antenna in an integrated configuration. The two strip monopoles contribute two additional resonant modes to incorporate those generated by the loop-type antenna to achieve the desired wide lower band (698–960 MHz) and upper band (1710–2690 MHz) for eight-band LTE/GSM/UMTS operation. Details of the proposed antenna are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1471–1476, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25257