Dual-band antenna system for SDARS and GPS applications

This paper presents a dual frequency band circularly polarized antenna system for Satellite Digital Audio Radio Service (SDARS) and Global Positioning System (GPS) applications. The proposed dual band antenna system consists of two circular patches each having four perpendicular slots for operating in two different frequency bands with left-handed circular polarization (LHCP) for SDARS and a right-handed circular polarization (RHCP) for GPS. The circular polarization characteristics for both antennas are obtained by choosing appropriate lengths of four perpendicular slots on the circular patches. The LHCP or RHCP radiation is readily obtained by selecting the proper feeding location. Results are presented in terms of the |S11|, radiation pattern and axial ratio.