Circularly-polarized microstrip array with low-sidelobe for RFID application

In this paper, a 4 times3 elements coplanar feed array is designed to obtain narrower beam width, higher gain and to optimize the feed network for low-sidelobe level in the horizontal plane. In order to achieve the low-sidelobe and narrow beamwidth characteristics, the array was synthesized by means of Chebyshev distribution in the horizontal direction and equal distribution in the vertical direction. A test array was fabricated and measured to verify the design.