4. Transceivers for the Fourth Industrial Revolution. Millimeter-Wave Low-Noise Amplifiers and Power Amplifiers

In this chapter, a review is presented on receiver subsystem-level of the low noise amplifier (LNA) in a millimeter-wave (mm-Wave)-compatible fifth-generation (5G) transceiver to identify the challenges and limitations of this subsystem at microwave operation (referring specifically in this context to centimeter-wave (3–30 GHz) and mm-Wave (30–300 GHz) operation. In this chapter, the expressions mm-Wave and microwave operation are used interchangeably and this includes mm-Wave frequencies. An overview of the considerations of the power amplifier (PA) in the transmitting front-end is correspondingly presented in this chapter, with a similar analysis of its microwave operation for 5G communications. Although the 5G specification allows for various options for carrier modulation, power levels, data rates and other capabilities as reviewed in Chap. 1 of this book, many of the performance characteristics are derived from the transmitter and receiver front-ends, more specifically the quality of the operation of the LNA and the PA. The LNA is responsible for receiving a weak, noisy signal and (ideally linearly and efficiently) amplifying this signal to a usable level without adding noise. Numerous LNAs have been used that are specifically designed for lower-GHz operation (such as for the 2.4 GHz and 5 GHz bands), but difficult operation in the mm-Wave 5G domain increases the complexity of these circuits significantly. Not only is it necessary for the architecture and topology of the LNA to be optimized for mm-Wave operation; the process technology and transistor type should also be considered based on their merits that are applicable and required for a specific application. Improvements on technologies such as “complementary metal-oxide semiconductor (CMOS), bipolar CMOS silicon germanium (SiGe), silicon-on-insulator and gallium arsenide field-effect transistors” are being researched to improve LNA performance from process level through inherent characteristics of the materials, such as leakage currents and electron mobility. References in this chapter to the process technologies are made for the subsystems being reviewed, and a detailed summary of the benefits and drawbacks of the various processes is presented in Lambrechts and Sinha [16]. In this chapter, a review of the fundamentals of LNAs and PAs is presented, along with an analysis on circuit level of the architectures that are typically used for high-frequency operation. The scope of this chapter is limited to describing the performance aspects of the LNA and the PA in terms of their architecture. This technical overview allows the reader to understand the performance limitations when designing transceiver subsystems for 5G communications; the overview does not aim to derive all performance metrics, as this has been reported in various works, referred to throughout this chapter. The subsequent chapters of this book focus on a techno-economic perspective of 5G the fourth industrial revolution, concentrating on emerging markets. Thorough understanding of the limitations and complexities of microwave circuit design is encouraged to avoid underestimating the skills required from researchers and engineers to implement and sustain the technology in these markets. Together with Chap. 2 of this book, the subsystems that are required to process high-frequency signals within a mm-Wave 5G communications system are therefore identified and reviewed. This provides the necessary background to implement these types of systems in preparation for big data communications.