INTERNAL WWAN ANTENNA FOR THE CLAMSHELL MOBILE PHONE WITH VARIOUS CHASSIS SHAPES

Stable performances of an internal WWAN antenna applied in the clamshell mobile phone with various chassis shapes are obtained. Six different states including,five possible operating states and one closed state (idle condition) of the clamshell mobile phone, wherein the chassis shapes (main ground and upper ground) vary greatly, are studied. The WWAN antenna is mounted at the bottom of the main ground, and there are three connecting positions between the main ground and the upper ground. For each operating states, the upper ground is connected to the main ground at one of the three connecting positions. At each position, a band-stop circuit formed by two parallel LC chip elements is embedded, which is designed to excite a parallel resonance at around 900 MHz and hence leads to very high impedance seen into the upper ground in the 900 MHz band. This greatly decreases the excited surface currents on the upper ground, making the presence of the upper ground to have very small effects on the performances of the WWAN antenna mounted at the bottom of the main ground. At around 1900 MHz, owing to its shorter wavelength, the surface currents on the upper ground excited by the WWAN antenna on the main ground are small. Thus, over both the 900- and 1900-MHz bands, the various orientations of the upper ground to the main ground cause small effects on the WWAN antenna embedded therein. Details of the obtained results are presented. (C) 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2148-2154, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25413