STRUCTURE OF A CIRCULARL POLARIZED ANTENNA FOR UHF BAND RFID READER

摘要

A structure of a circular polarized wave antenna is provided to accurately recognize a plurality of tags at a long distance by minimizing an error due to multipath signals. A signal generating part divides an original signal into two signals having a phase difference of 90 degree. A pair of strip lines is formed in a radiation patch(110), and performs a circular polarized wave after receiving the signals. A radiation plate(130) has two feeding points which are separated from the radiation patch in order to improve radiation efficiency. The radiation patch and the radiation plate have different sizes. A hybrid coupler is mounted in the radiation patch, and divides the original signal into the two signals having a phase difference of 90 degree.