Circular polarized patch antenna for 5.8 GHz dedicated short-range communication

A circular polarized patch antenna for the 5.8 GHz dedicated short-range communication (DSRC) band is proposed. This frequency band includes road transport and traffic telematics (RTTT) applications, which impose severe cost and size limitations on microwave RTTT devices. The patch antenna is based on low-cost, but lossy, FR-4 material. It consists of a rectangular radiator patch, which is fed by a single feed point, Because of the size limitations, detuning and power loss caused by the device case are taken into consideration. A design method for the antenna, which is based on EM simulations and equations, is given. The proposed 5.8 GHz patch antenna shows low sensitivity to manufacturing tolerances. EM simulation results are compared to theoretical considerations and measurements results. Special attention has been given to the radiation pattern and cross-polarization ratio, which both are regulated by RTTT standards.