Wideband Linearly-Polarized and Circularly-Polarized Aperture-Coupled Magneto-Electric Dipole Antennas Fed by Microstrip Line With Electromagnetic Bandgap Surface

Wideband aperture-coupled magneto-electric (ME) dipole antennas fed by microstrip line are proposed in this paper. The aperture-coupled microstrip-line-fed method was utilized in the proposed configuration to replace the conventional Γ-shaped probe to excite the ME dipole antenna. Particularly, a printed mushroom-like electromagnetic bandgap (EBG) surface was mounted below the microstrip line to effectively eliminate the back radiation caused by the aperture on the ground plane. Two configurations of ME dipole antennas with linear polarization (LP) and circular polarization (CP) have been proposed for adequately studying the effect of the EBG surface. Both the simulation and measurement of the two prototypes had been carried out for verification. Based on the measured results, wide impedance bandwidth (SWR <; 2) of 54.9% and 58% can be obtained for both the proposed LP and CP ME dipole antennas, respectively. Besides, the performances of the stable broadside radiation pattern with the enhanced front-to-back ratio (FBR) can also be achieved for both configurations.