Internet of meta-material things (meta-IoT) is a network of sensors composed of meta-materials with the advantages of low cost, ultra-low power consumption, and robust, showing great potential for the coming 6G communications. However, existing meta-IoT systems assume specular reflection on meta-IoT sensors, which limits their applications. For example, in chemical factories with harsh environments, receivers are often deployed on mobile robots. Due to their mobility, when measuring the signals, it is infeasible to ensure that the receivers are located at a certain angle relative to the meta-IoT sensors. Therefore, it is necessary to broaden the angle range of reflected signal coverage. In this paper, we propose a meta-IoT system capable of supporting receivers deployed at arbitrary angles in a broadened angle range. To be specific, we first propose an inhomogeneous structural design for meta-IoT sensors to achieve reflection coverage broadening. Then, we establish the signal transmission model from the transmitter to the receiver, going through the proposed meta-IoT sensor. To maximize the reflection coverage while ensuring accurate sensing results, we formulate a joint meta-IoT structure and sensing function optimization problem and propose efficient algorithms to solve it. Simulation results verify the effectiveness of the design method for the proposed meta-IoT system to achieve reflection coverage broadening.