Microwave and Millimeter-Wave Shared-Aperture Antenna Using Bifunctional Slot and Integrated Decoupling Structure for Smart Glasses

This letter presents a microwave and millimeter-wave shared-aperture antenna for smart glasses. It consists of a hook-shaped open-ended slot, an F-shaped open-ended slot, four millimeter-wave patches and parasitic strips. It is novel that the hook-shaped slot is used to simultaneously feed millimeter-wave patches and realize 2.45-GHz radiation. To achieve high cross-band isolation between microwave and millimeter-wave radiators, a coupled feeding structure is designed for each millimeter-wave patch. By using parasitic strips, the hook-shaped slot is equivalent to be a complete resonant slot in three quarter-wavelength mode at 2.39-2.53 GHz, and divided into four segmented feeding slots for millimeter-wave patches. In-band isolation between millimeter-wave elements is enhanced to be 24.6 dB by parasitic strips. Measured results demonstrate that the proposed antenna has omnidirectional radiation pattern at 1.22-1.59 (Global Navigation Satellite System, GNSS), 2.39-2.53 (Wi-Fi) and 3.17-3.78 GHz (5G-n78 band). The beam scans from -42°to +40° with a gain of 10.1 dBi at 24.1-26.8 GHz (5G-n258 band). The cross-band isolation level is over 19.9 and 27.4 dB at 1-4 and 24.1-26.8 GHz, respectively. Compared with previous works, the proposed antenna has compact size, wider bandwidth and better millimeter-wave beam-scanning performance, and simultaneously supports microwave and millimeter-wave communication.