Chapter 2 - Characteristics of Planar Transmission Lines

Abstract

There are several reasons for the wide use of planar transmission lines. ,The planar transmission lines are broadband, while providing compact dimensions and light-weight and are generally economical to produce, as they are readily adaptable to hybrid and monolithic integrated circuit fabrication technologies at RF and microwave frequencies. In general, planar transmission lines consist of strip metallic conductors, usually produced by some photographic process, on a non-conducting substrate. Typical substrate materials are slabs of dielectric, ferrite, or high-resistivity semiconductors. In most cases, there are metal ground planes that can either be printed on the same substrate or be a part of the metal housing of a microwave integrated circuit (MIC), which is discussed in the chapter. The chapter also decribes commonly used types of planar transmission lines for MICs. Each of these types offers certain advantageous features with respect to other types. The various features of the different types are illustrated and discussed in this chapter.