A Compact 3D Printed Mirror Folded Lens Antenna for 5G Applications
Dr. Bin Xu
Progress In Electromagnetics Research C, Vol. 131, 35-48, 2023
A concept to minimize the volume of the classic bifocal elliptical lens antenna is proposed. By applying the image theory, a reflective ground plane is placed along the short axis of a bifocal elliptical lens. An antenna-on-chip (AoC), as the lens's feed source, is placed at the upper focus and packaged by the lens body. The AoC radiates toward the ground plane instead of the free space. The geometric optics (GO) ray tracing analysis shows that the optical path of the miniaturized monofocal integrated lens antenna (ILA) is equal to that of the classic bifocal ILAs, so the gain is almost unaffected on the basis of the lens' volume reduction. For the quantitative evaluation of the gain loss caused by feed occlusion, a set of analytical equations is given. To verify the design concept, a 26 GHz miniaturized self-packaged monofocal elliptical ILA is designed and fabricated by 3D printing technology. The ILA achieves a 26.5 dBi gain and a size reduction rate of 38% compared with the classic bifocal elliptical lens. Moreover, the ILA also functions as the package for the AoC's die. The proposed design concept can not only reduce the volume of the classic bifocal elliptical lens dramatically but can also save the effort and cost to package the AoC's die in a highly integrated system, which is believed to have great potential to create large profit margins for the fifth-generation (5G) mobile network applications.