A Wideband 3-D-Printed Multibeam Circularly Polarized Ultrathin Dielectric Slab Waveguide Luneburg Lens Antenna

This letter presents a wideband three-dimensional (3-D)-printed circularly polarized (CP) ultrathin dielectric slab waveguide (DSW) Luneburg lens (LL) with multibeam application in X-band. The characteristic that DSW supports TE0 and TM0 waves to pass through with different phase constants is used to generate 90° phase difference to compose CP wave for the proposed structure. To prove the point, the prototype antenna is fabricated by 3-D printing and measured. The results show that the proposed LL supports multibeam application with 11 beams covering ±60° range in azimuth plane, and the 3 dB axial ratio bandwidth for multibeam antenna is 23.5% with reflection coefficient lower than -10 dB and gain higher than 13.7 dBi. The measured results show good coincidence with simulated ones.