Millimeter-Wave Wideband Dual-Beam Endfire Dielectric Resonator Antenna

A dual-beam endfire dielectric resonator antenna (EFDRA) with wideband performance for millimeter-wave application is proposed. An equivalent electrical wall composed of three metal strips and a row of metal vias is introduced to the middle position of the dielectric resonator (DR) and connected with the T-shaped feeding structure to achieve wideband dual beam by generating the modified TE_12δ mode and the anti-phase TE_13δ mode. The two modes can be equivalent to two and four anti-phase magnetic currents, respectively, which can both support dual-beam endfire radiation and form wideband design. Meanwhile, the vertical E-field components contributing to unwanted broadside radiation in the two modes will cancel each other out because they are distributed symmetrically in even numbers with similar amplitude and anti-phase, thus restraining broadside radiation. The T-shaped feeding structure is used to generate anti-phase currents, which can simultaneously excite the two modes. Compared with the state-of-the-art dual-beam endfire antennas, the proposed antenna shows a wider bandwidth and higher radiation efficiency. For demonstration, a wideband dual-beam EFDRA prototype is designed and measured. The proposed antenna achieves a 10 dB impedance matching bandwidth of 27.6% [(21.2 to 28) GHz] with a stable direction of the dual beams.