Internal Coupled-Fed Shorted Monopole Antenna for GSM850/900/1800/1900/UMTS Operation in the Laptop Computer

A simple shorted strip monopole with a coupling feed for penta-band WWAN (Wireless Wide Area Network) operation in the laptop computer is presented. With the coupling feed, which effectively compensates for the large inductive reactance of the antenna, a dual-resonance excitation for the antenna's lower band at about 1 GHz is achieved; the obtained bandwidth reaches 500 MHz, allowing the antenna to easily cover GSM850/900 operation. Also, a wide operating band is achieved for the antenna's upper band at about 1.9 GHz with a bandwidth of 540 MHz, hence easily covering GSM1800/1900/UMTS operation. With two wide operating bands achieved, the antenna occupies a thickness of 5 mm only and a small area of 9 x 79 mm(2) (not including the ground plane), making it very promising to be embedded inside the casing of the laptop computer as an internal WWAN antenna. The proposed antenna is studied in detail in this study.