A Study on 28 GHz Power Amplifiers for Industrial Revolution 4.0 Compatible 5G NR FR2 IoT Transceivers

Industrial Revolution 4.0 (IR 4.0) has always been a hot topic to be discussed along with the Internet of Things (IoT). With current 5G wireless technology, IoT systems are able to be connected even wider and can cover more applications such as AI/ML, edge computing, and smart factories. 5G NR have standardized FR1 and FR2 bands, and FR2 have the potential to establish the network for Industrial-IoT (I-IoT) system. Although FR2 have limits on transmission distance, a power amplifier (PA) located in the transmitter circuit is able to boost the distance with its produced high output power. In this paper, we will investigate the potential of 5G NR FR2 28 GHz for I-IoT applications and review the available state-of-the-art PA designs and their available modulation scheme. Each PA design in this article will be discussed, and compared. This paper will serve as a small review for authors to design PA for I-IoT applications in the 5G NR FR2 band.