Small-size multiband planar antenna for LTE700/2300/2500 operation in the tablet computer



A small-size multiband planar antenna can be obtained using a long parasitic shorted strip and a monopole feed encircled by the same. Such a configuration can lead to a small antenna size for multiband operation, and a promising design with a small size of 12 × 35 mm2 for covering three-band LTE700/2300/2500 operation (704–787/2300–2400/2500–2690 MHz bands) in the tablet computer is presented. The antenna is easy to fabricate on one surface of an FR4 substrate and is composed of an inverted-L strip as the monopole feed and a long parasitic shorted strip encircling the inverted-L monopole. The long shorted strip is parasitically excited to generate a 0.25-wavelength resonant mode at about 750 MHz to cover the LTE700 operation, while the inverted-L monopole generates a 0.25-wavelength resonant mode at about 2.5 GHz to cover the LTE2300/2500 operation. Details of the proposed antenna are described. Radiation characteristics of the antenna and its body specific absorption rate results for tablet computer applications are also presented. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:81–86, 2012; View this article online at DOI 10.1002/mop.26507