“…This antenna can provide wide impedance bandwidth, identical E-plane and H-plane radiation patterns, stable gain and low back radiations [1,2]. Despite the antenna has shown excellent performance with a staircase-shaped structure [3][4][5][6], where additional need of balun may be removed and antenna can provide dual-band with wide impedance bandwidth and high gain, with differential feeding structure [7,8], where the originally single ended operation is converted into differential ended to provide ultra-wide band, theoretically infinite differential port to port isolation and to be directly connected to differential microwave circuits, and with dielectric material [8][9][10], where magneto-electric dipole antenna is printed on dielectric material, it suffers from disadvantages of being bulky and pertaining complex structures. In [11][12][13], circular polarization has been achieved with 3-dB axial ratio bandwidth of 42.9%, 61.5% and 82% respectively, but the magneto-electric dipole antenna structure is non-planar.…”