Wideband Millimeter-Wave Antennas With Magnetic-Dipole Patterns Integrated in Metallic Structures

Two realizations of millimeter-wave (mm-wave) antennas with wideband and broad beam characteristics are introduced for flush integration in metallic structures. The antenna design exploits the half-mode substrate-integrated waveguide structure and its characteristic radiation loss close to cutoff. The target bandwidth extends from 30 to 40 GHz. The proposed antennas are analyzed and optimized using a highly efficient and accurate semianalytical solution with dedicated considerations of the losses in mm-wave band as well as optimization with emphasis on the radiation pattern quality. The transition is carefully designed for structure integration and for reduction of discontinuity-induced ripples in the radiation patterns over the wideband operation. Good agreement between the analysis, simulation, and measurement results validates the theoretical approach of the designs. The unique characteristics make the proposed antennas excellent candidates for future wireless communication systems requiring broad beam and horizontal polarization.