Design of microstrip antenna and RF circuit for robust wireless communication of IoT devices under partial shield installation

In recent years, smart devices are popular in residents and commercial offices, which are often integrated into Internet of Things (IoT). To achieve it, those IoT devices often utilize microstrip antennas due to their low cost, low profile, and ease of forming antenna arrays. However, they may be installed inside the steel truss walls for the beauty of the environment. The partial metal shield is observed to reduce the signal strength significantly and blocks the wireless data transmission among those IoT devices over a long distance. This paper's objective is to design and fabricate an inverted-U shape microstrip antenna and 433MHz radio frequency circuit, which has a good performance even under partial shield installation. The method is to optimize the impedance matching circuit with side and rear metal shields. The experiments confirm that this new design has robust wireless communication among multiple IoT devices over 40-meter indoor and 100-meter outdoor environment.