Development of a small form factor switched-beam antenna for IoT applications at the 868 MHz ISM band

In this paper, the design and development of a Switched-Beam Array (SBA) antenna for WSN and IoT networks at the 868 MHz frequency range is presented. Our motivation is to contribute to the improvement of the capacity and energy consumption of such networks by using SBAs that have been proven capable to decrease interference and node collision. Our contribution lies in a small-form factor yet efficient antenna design of favorable performance for the size-demanding frequency of 868 MHz. The proposed antenna achieves two different switching beams, intended for during active operation, and an omnidirectional radiation pattern for idle operation (listening mode). Furthermore, it does so with not at all or minimal matching components. The infrastructures of the University of West Attica (UNIWA) and the EMC Hellas S.A. were used for its simulation, implementation and measurements, while measurements results show good agreement with simulated data.