A Multimode Antenna Design with Polarization Diversity

In this article, a multimode antenna with polarization diversity is designed for smartwatch applications. The antenna structure consists of a circular watch frame and a circuit mainboard. Two ports are used to excite the antenna in odd and even modes, and polarization-diversity resonances are achieved. Additionally, a circular current is excited on one port to realize low-frequency multimode operation. Furthermore, high-order modes are excited by introducing slots in the circuit board, enabling multiband and multimode operation. The port 1 is working at 2.45 GHz, 4.1 GHz, and 5.8 GHz. And Port 2 works at 0.82 GHz 2.45 GHz, 4.1 GHz. and 5.8 for ISM band. The proposed antenna exhibits stable radiation patterns and high port isolation across multiple frequency bands, making it a promising candidate for next-generation smartwatch devices.