This book presents the papers presented at the 12th International Conference on Communications, Circuits, and Systems (ICCCAS 2023) held 5–7 May, in Singapore. It covers advanced research topics in the fields that encompass the design, analysis, and optimization of circuits and systems that enable communication between devices and networks, including but not limited to RF and microwave circuits, wireless communication systems, digital signal processing, power electronics, and control systems. It is expected that the collection and publication of those research papers with the advanced topics listed in this book will further promote high-standard academic research in the field and make a significant contribution to the development of economics and human society.