TABLE OF CONTENTS This chapter describes a family of transmission line transformers that was not included in earlier editions of this book. There are two distinct paths of development for these transformers, each of which can be characterized as achieving a more generalized form of transformer derived from the earlier work of Ruthroff and Guanella. Although parallel development was done by others, this chapter describes the work of W.A. Lewis at Collins Radio (Ref 41), [1] which was further developed by Blocksome at Collins (now a division of Rockwell) (Refs 42-43), and independent work by McClure at RCA (Refs 44-45).
[1]References (1-36) are in Chapter 15, additional references are in Chapter 19.
The work of McClure was specifically directed toward the development of fractional-ratio transformers, while the work at Collins Radio included both integer and fractional ratio transformers. Although thereare differences in these approaches, one of the primary reason for these development efforts was done to obtain a wider range of transformation ratios than the basic 1:4, 1:9, 1:16 and so on that characterized earlier work in this area.
Most transformers explored in the previous chapters are designed for transformation ratios of n 2 or 1/ n 2, where n is an integer. There are, however, many applications where other impedance transformation ratios are desired. Examples include a 1.5:1 ratio for matching between 50-ohm and 75-ohm transmission line systems and 2:1 or 1:2 ratio...
