Circularly polarized microstrip antenna with slots for Beidou(COMPASS) Navigation System

A single layer, single-feed circularly polarized (CP) microstrip antenna designed with four slits equally spaced and inset at the boundary of the circular patch for Beidou (COMPASS) Navigation System is proposed. The experimental results shown that by simply tuning the lengths of the slotted pairs, two orthogonal near-degenerate resonant modes for CP radiation can be excited. The measured impedance bandwidth corresponding to return loss less than -10dB of 0.09GHz and the 3dB axial ratio (AR) bandwidth of 0.033GHz have been achieved for the antenna which is designed at 2.492GHz. Details of the experimental results are presented and analyzed.