A compact microstrip antenna for GPS and DCS application

This communication presents a novel design of a compact microstrip antenna practical for both the global positioning system (GPS) and digital communication system (DCS). The proposed antenna consists of two parts: a fundamental mode truncated square patch antenna and a higher-order mode annular ring patch antenna. The truncated square patch operated in right-hand circular polarization at 1575 MHz with 8-MHz CP bandwidth, making the design suitable for the GPS. Further, four slots were embedded into a ground plane to meander the current path of the annular ring patch at the TM₂₁ mode, which considerably lowered the resonant frequency and effectively increased the impedance bandwidth. These features reduce the antenna size and make the design appropriate for DCS. Both radiators are placed in a common space but operate independently. The experimental results show that this design is ideally suited for GPS/DCS dual-band mobile communications.