Abstract
The deployment of wireless devices has increased exponentially in recent years, not only for mobile applications but also for IoT. Typically, these IoT devices exchange data with other devices by means of wireless connections, where battery consumption depends on the antenna system's efficiency. In applications where long battery life and reliable transmission are essential, improving the efficiency of the antenna is crucial. This study aims to investigate how shaping the ground plane of a wireless device can enhance bandwidth and antenna efficiency, specifically in low-frequency bands of 824-960 MHz, a common frequency band used in IoT where transmitting a small amount of data provides long battery life. Specifically, this work shows that by adding a slot in the ground plane, the current distribution is enlarged, which enables the excitation of its fundamental mode and, consequently, enhances the bandwidth and antenna efficiency by 2 dB. This approach is assessed using three different printed circuit boards (PCBs) that aim to characterise different form factors of IoT devices. A physical prototype is built to validate the results obtained in simulations.