Dual-Linear or Dual-Circular Polarized Slot Excited ME-Dipole Antenna with Single-Layer Feeding

A magnetoelectric (ME) dipole antenna with a single-layer microstrip line feeding network is proposed for either dual-linear or dual-circular-polarizations. To achieve better isolation, a hook and fork-shaped feedlines are designed to excite dual linear polarizations, which are combined with a quadratic hybrid to provide dual-circular polarizations. Furthermore, in the proposed feeding configuration, the isolation level is tuned properly according to the requirements. The operational bandwidth of the antenna (impedance bandwidth <; -10 dB, Isolation > 30 dB (linear) and > 20 dB (circular), and Axial Ration <; 3 dB) is 23% at 30 GHz. The average radiation efficiency and maximum gain of the antenna are calculated to be 95% and 9.2 dBi, respectively.