A Wideband Endfire Double Dipole Antenna Fed From Double-Ridge Gap Waveguides for Multibeam Array Application

In this letter, an endfire double dipole antenna fed from double-ridge gap waveguides (DRGWG) is proposed and designed for multibeam array application. Two dipoles with different lengths are connected to the extension of the ridges of DRGWG in series. Different resonances can be generated by these two dipoles, which contributes to a wide impedance bandwidth, high gain, and stable radiation patterns across the working band. The double dipole antenna is vertically polarized and has a wide H-plane beamwidth suitable for beam scanning application. To verify the performance of the double dipole antenna, a Butler matrix is designed based on ridge gap waveguides to feed a 1 × 4 double dipole array arranging in H-plane. The maximum gains achieved for Ports 1 and 2 are 13.94 and 12.68 dBi, respectively. Besides, the simulated radiation efficiencies for Ports 1 and 2 are both above 83%.