Small‐size internal eight‐band LTE/WWAN mobile phone antenna with internal distributed LC matching circuit

Abstract

AbstractA coupled‐fed planar inverted‐F antenna (PIFA) to be mounted at the small no‐ground portion of the system circuit board of the mobile phone with a low profile of 10 mm to the system ground plane and a thin profile of 3 mm to the system circuit board is presented.The proposed small‐size PIFA is formed by a simple structure of two radiating strips of different lengths, both capacitively fed by a coupling feed and short circuited to the system ground plane by a shorting strip. The coupling feed and shorting strip together function as an internal distributed LC matching circuit, with the coupling feed as a capacitive element and the shorting strip as an inductive element. This internal distributed LC matching circuit has an equivalent layout as the conventional external high‐pass LC matching circuit with lumped elements; both are effective in tuning the antenna's lower band bandwidth. In addition, the antenna with the proposed internal distributed LC matching circuit, in this study, can lead to much widened bandwidths in both the antenna's lower and upper bands to cover the 698–960 and 1710–2690 MHz bands, respectively. That is, eight‐band LTE/WWAN operation can be achieved. Results of the proposed antenna with the internal distributed LC matching circuit are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2244–2250, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25431