A low-profile antenna solution for mobile phones with GSM, UMTS and WLAN operation

A novel low-profile antenna solution for mobile communication devices consisting of a first antenna for EGSM and DCS, a second dual-band antenna for the Tx and Rx bands of UMTS and a third antenna for standards operating in the ISM 2.4 GHz and 5 GHz frequency bands (WLAN and Bluetooth) is presented in this paper. Our antenna concept is based on a dual-layer approach. The λ/4 resonances of the radiators on top and bottom layer are used to form a dual-band resonator antenna. The main advantage of the proposed structure is the very low profile of the antenna with no additional height above the substrate. This might be an issue for other multi-band antennas based on a folded planar inverted-F antenna (PIFA). In the future devices for mobile communication become even smaller than today. A minimal height (flatness) of these products is a design criteria. Our printed antenna arrangement is an ideal candidate for those applications. The performance of the antenna test board has been simulated using commercial FDTD/FEM software tools. These simulation results have been validated with measurements on a fabricated prototypes.