A Two-Dimensional Multibeam Lens Antenna for Hydrologic Radar Application

A K-band multibeam lens antenna is reported for hydrological radar applications. It is designed with a shared aperture and drifted feeds on elevation and azimuth. The feeds shift off the focal point of the lens onto a planar plane, which generates multibeam by refraction, meanwhile easing the mounting of the lens on a smooth surface. A conical horn array is designed as the feed for increased gain and better power capacity. Both dielectric and metallic three-dimensional printing technologies are adopted for fabrication. Measurement results agree with simulation, showing an impedance bandwidth of 18-25 GHz. The boresight gain lies in the range of 24-29 dBi. It radiates seven beams ±34° symmetrically on elevation and azimuth. Mutual coupling between adjacent ports is below -30 dB. The proposed multibeam lens enriches the choices for hydrological radar applications, in which a large area or multiple targets shall be looked upon from distance away.