Ultra-wideband, dual-mode millimeter-wave micro hemispherical shell antenna

This paper presents a novel ultra-wideband millimeter-wave micro-hemispherical shell antenna. The antenna is comprised of a hemispherical metallic shell with a diameter of 800-1200 microns and a thickness 3-5 microns suspended above a high-resistivity substrate. It can be fabricated using a fabrication technology originally developed for micro-scale hemispherical shell resonators. The antenna can operate in two separate operational modes with the same feeding structure, common and differential mode, demonstrating omnidirectional and directive radiation pattern respectively. An ultra-wide bandwidth of more than 60 GHz at the common mode and more than 80 GHz at the differential mode is achieved in the millimeter-wave regime.