A novel dual-linear polarized ultra-wideband magneto-electric dipole antenna with gain improvement

A novel magneto-electric dipole antenna with dual linear polarization, ultra-wideband, and good unidirectional radiation is proposed. It consists of two bowtie-shaped electric dipoles, two orthogonally placed Gamma-shaped feeding structures, four parasitic patches, and a metal cylindrical cavity. In order to illustrate the operating mechanism, the radiation field is simulated and analyzed at lower, medium, and higher frequencies. Three operating modes (electric dipole mode, ME dipole mode, and magnetic dipole mode) are found and discussed to show the ultra-wideband radiation. Especially, the ME dipole mode is analyzed in detail. By adding four parasitic metal patches, the boresight gain at the lower and higher bands is enhanced. At 1.75 and 5.6 GHz, the boresight gain improves 1.65 and 2.8 dB, respectively. Additionally, the height of the cylindrical cavity is also analyzed to show its effect on VSWR and boresight gain. Finally, a prototype is designed, fabricated, and measured. Measured results show that the impedance bandwidth for VSWR <2 is up to 92.3% (from 2.1 to 5.75 GHz) and 103% (from 1.8 to 5.65 GHz) at the two feeding ports, respectively. In its impedance bandwidth, the boresight gain is 8.75 +/- 1.95 dBi and 8 +/- 3.3 dBi at two ports, respectively. And, the radiation patterns in the operating band show a unidirectional radiation characteristic. Therefore, the proposed antenna can be a candidate in the future UWB communication system.