A 3D-Printed Subterahertz Metallic Surface-Wave Luneburg Lens Multibeam Antenna

This letter presents an experimental realization of a subterahertz metallic gradient index (GRIN) lens multibeam antenna operating at 355 GHz. The antenna is composed of a surface-wave Luneburg lens based on a bed of nails and a feeder array of nine WR-2.2 waveguides. The lens and the feeding structures are fabricated by the same high-precision 3D printing technique and are metalized using magnetron-sputtering gold coating. The antenna has been measured, showing good reflection coefficients below −12.5 dB at all ports and multiple independent beams covering a range of ±60°, which agree very well with the simulation. The measured gains are above 16 dBi and the scan loss is below 1.2 dB. This work demonstrates a novel manufacture and implementation approach for metallic multibeam lens antennas at subterahertz frequencies.