A Lightweight 3-D Printed Dual-Band High-Gain Slotted Spherical Antenna

A new class of slotted spherical antenna is proposed in this letter. The antenna is composed of a single air-filled high-quality-factor spherical resonator that is properly slotted on the cavity shell, and is fed by a rectangular waveguide on the other side of the slots, radiating the TM101 and TM211 modes. A 3-slot antenna prototype operating at X and Ku bands is designed and implemented as proof of concept. Good directional radiation patterns are achieved at both bands by optimizing dimensions of the three circumferential slots. The prototype is additively and monolithically manufactured by incorporating stereolithography apparatus and electroless copper plating techniques, showing enhanced flexibility and improved efficiency in the fabrication. The antenna demonstrates a light weight (11.2 g) and a reflection coefficient below -10 dB at the lower band from 9.88 to 10.68 GHz and the upper band from 13.05 to 15.05 GHz, with the maximum realized gains of 8.8 and 10.1 dBi, respectively.