Digital Twin (DT) technology is emerging as a powerful tool for optimizing energy efficiency and industrial sustainability. By creating virtual replicas of physical systems, DTs enable real-time monitoring, predictive maintenance, and resource optimization, offering new opportunities to meet growing energy demands. Despite its potential, the comprehension of DT technology’s applications, benefits, and challenges remains limited. This systematic review explores the role of Digital Twins in energy efficiency across various industries. A structured literature search was conducted in IEEE Xplore, Elsevier, Springer, MDPI, and Google Scholar, following PRISMA 2020 guidelines. After applying the predefined inclusion criteria, 50 studies were selected for in-depth analysis. The findings highlight that DT implementation can lead to energy savings of up to 30%, reduce operational costs, and improve predictive maintenance strategies. Their impact is particularly notable in smart buildings, manufacturing, and industrial processes, where real-time data analytics contribute to better energy management. However, significant barriers remain, including high implementation costs, data security risks, and the complexity of integrating DTs with existing infrastructures. By synthesizing the current research, this review underscores the transformative potential of Digital Twins while identifying key challenges that need to be addressed for their wider adoption. Future efforts should focus on developing standardized methodologies, reducing implementation costs, and enhancing cybersecurity measures to maximize their benefits in energy efficiency and sustainability.

In this study, a new approach for the design of microstrip antenna is proposed. The resonant frequency of the proposed antenna is 3.55 GHz allowing it to operate in the mobile network current 5G band (the mid band). The design approach is based on a wedge shaped substrate having relative low thickness at the level of the feed line and a higher thickness at the level of the radiating patch. The FR4 wedge substrate based design of 6 mm linear slope enhance the radiation by 9% and the bandwidth by 10.3 % while degrading the return loss by 2.3 dB with respect to a standard box substrate based antenna design of the same dimensions. To remedy the degradation in terms of S11, the rectangular inset feed line is replaced by a trapezium one which re-enhance the return loss by 3.4 dB and then making it better than the original one.