On March 2007, the national specifications of China on
ETC&DSRC, GB/T20851-2007[2], had been published. Some
needs on the reader's antenna have been defined in it.
According to the specifications, the microstrip antenna array is
the leading choice for the RSU because of its low cost, low
profile and ease of fabrication[3] as well as the gain of the array is easy to meet the demands.