Foreign object debris (FOD) in airport runway can damage aircraft or harm personnel on board, resulting in huge economic losses. For the sake of preventing FOD efficiently, many studies adopt millimeter-wave radar for FOD detection. However, due to the limited coverage of single millimeter-wave radar, there exists the possibility of overlooking certain debris. This paper addresses this limitation by presenting a solution that involves deploying multiple millimeter-wave radars and implementing a client/server model based on LoRa (Long Range) technology to integrate them into the Internet of Things (IoT). In this proposed system, multiple millimeter-wave radars are strategically positioned at equal distances along the airport runway, each connected to a LoRa device serving as the client side. The main control center computer at the airport establishes a connection with a LoRa device functioning as the server side. Through these LoRa connections, the multiple millimeter-wave radars and the central computer are seamlessly integrated into an IoT framework. A dedicated application program is designed for the radar-LoRa client side to collect and process data received by the radar, filtering out extraneous information such as clutter. Relevant information is then transmitted to the computer LoRa server side through LoRa communication. On the computer LoRa server side, a software algorithm is developed to receive FOD data from multiple radars, integrating them into a unified coordinate system for real-time display on a software application window. Airport personnel receive FOD coordinates, enabling them to locate, retrieve and remove debris. Simultaneously, the software application on server side updates FOD information in real-time. Experimental results demonstrate the effectiveness of this IoT-based solution in detecting FOD on airport runways. The paper discusses and analyzes challenges encountered during experiment and proposes new future research.