Chapter 3 Basic concepts and theories of filtersMicrostrip Filters for RF/Microwave Applications. Jia-Sheng Hong, M. J. Lancaster Copyright 2001 John Wiley & Sons, Inc. ISBNs: 0-471-38877-7 (Hardback); 0-471-22161-9 (Electronic) CHAPTER 3 Basic Concepts and Theories of Filters This chapter describes basic concepts and theories that form the foundation for design of general RF/microwave filters, including microstrip filters. The topics will cover filter transfer functions, lowpass prototype filters and elements, frequency and element transformations, immittance inverters, Richards’ transformation, and Kuroda identities for distributed elements. Dissipation and unloaded quality factor of filter elements will also be discussed. 3.1 TRANSFER FUNCTIONS 3.1.1 General Definitions The transfer function of a two-port filter network is a mat……