Design of a Coplanar Integrated Microstrip Antenna for GPS/ITS Applications

This letter presents a novel low-profile coplanar multifunctional microstrip antenna for both global positioning system (GPS) and intelligent transportation system (ITS) applications. The multifunctional antenna consists of two parts: a directional coupled square-ring patch antenna and a center-fed square-ring loaded patch antenna. A coplanar simple single-fed method is proposed in the directional coupled square-ring patch antenna, which operates at the fundamental TMn mode with right-handed circular polarization at the GPS L2 frequency of 1.227 GHz. More-over, the square-ring is also utilized to load the center-fed square patch antenna at TM₀₂ mode with a vertical linear polarization for ITS application, which considerably increases the impedance bandwidth. Very good consistency between the measurement and simulation for the return loss and radiation patterns is achieved.