A planar triple-band antenna for GSM/DCS/GPS operations

With the rapid progress in wireless communications, the integration of different radio modules into the same piece of equipment has given a need for multiband antennas. It seems to be highly desirable to develop lightweight. low-profile, flush-mounted and single-feed mobile antennas, which can be used simultaneously in different frequency ranges and for different mobile services. In this paper, a planar single-feed triple-band antenna for GSM 900, DCS 1800 and GPS is presented. The proposed triple-band antenna is composed of a microstrip patch antenna and two triangular monopole antennas. An additional feeding network is also integrated into the triple-band antenna, which provides good impedance matching for each of three operating frequency bands and good isolation between different antenna ports. From the experimental results, it is shown that the impedance bandwidths, determined from 10 dB return loss, are 21.7% referenced to 920 MHz for GSM 900 and more than 33% referenced to 1795 MHz for DCS 1800, respectively. Furthermore, right-hand CP radiation and omni-directional patterns toward the upper hemisphere are also obtained for the GPS band.