Radio Frequency (RF) Filter Networks for Wireless Communications—The System Perspective

This chapter provides the sufficient background to be able to appreciate the critical role and requirements of radio frequency (RF) filters in wireless communication systems. It first presents a simple model of a communication system: the radio spectrum and its utilization, the concept of information, and system link budgets. The chapter then describes the noise and interference environment in a communication channel, the nonideal amplitude and phase characteristics of the channel, the choice of modulation‐demodulation schemes, and how these parameters affect the efficient use of the allocated bandwidths. It further explores information transmission over a medium by reviewing the seminal work of Shannon on information theory, highlighting the fundamental trade‐offs between signal power, noise in the system, and available bandwidth. The chapter concludes with a discussion of system requirements and the specifications of microwave filter networks in satellite and cellular communication systems.