Wide-Beam Circularly Polarized Microstrip Magnetic-Electric Dipole Antenna for Wide-Angle Scanning Phased Array

In this letter, a circularly polarized (CP) wide-beamwidth microstrip magnetic-electric dipole (ME-dipole) antenna is proposed. The antenna is comprised by a microstrip electric dipole and a cavity-backed slot. The electric dipole is excited by a coaxial probe directly, and the cavity-backed slot is excited by the coupling energy. φ-directional polarized electric field E
_φ
is generated by the current on the electric dipole. Meanwhile, θ-directional polarized electric field E
_θ
is generated by the equivalent magnetic current in the slot. When they have a phase difference of 90°, the CP radiation is obtained. The simulated and measured results show that the 3-dB beamwidth of the antenna is 128° and the CP beamwidth is 121° in the elevation plane. Furthermore, an eight-element linear phased array is comprised by the ME-dipole antennas. CP scanning is obtained in a wide-angle range. The measured results show that the array can scan the main lobe from -66° to 66°. Moreover the axial ratio of the main lobe is below 3 dB in the total scanning range.