Microwave Transmission-Line Impedance Data
A compendium of data for computing the characteristic impedance of transmission lines based on physical dimensions, this book covers both conventional structures and unusual geometries.
TABLE OF CONTENTS Microwave Transmission-Line Impedance Data
3.4: The Rectangular Coaxial Line
3.4 The Rectangular Coaxial Line
This is the "basic form" from which almost all of the other lines considered in this chapter can be derived, by suitable transformations and/or limiting processes which will be indicated where appropriate.
This basic structure consists of a conducting strip of rectangular cross-section (of width W ? and thickness t) which is (usually but not necessarily) axially and symmetrically located within an enclosing conducting shield, also of rectangular cross-section (of width W and height b), as shown schematically in Fig. 3-3.
Figure 3-3: Cross-section of the general rectangular coaxial line. ? is the dielectric constant of the medium filling the line interior.
3.4.1 Analysis of the General Rectangular Line
Although the structure is of a pleasing and simple symmetry, an exact general analysis is extremely difficult, and until recently none had been given. However, in [12] Sato and Ikeda (in a contributed chapter) have given a fairly comprehensive coverage of several types of microwave transmission lines, and, using conformal transformation techniques, have derived exact formulae for the various line parameters. Among these one can find some rather complex, implicit, but exact, formulae which can be used to determine the exact characteristic impedance of rectangular coaxial line of arbitrary cross-sectional dimensions.
Using present notation, these are as follows:
where
In a masterpiece of understatement, the authors baldly state that "These relations can be used to determine k." It is indeed true that, once k is known, the characteristic...
Copyright Noble Publishing Corporation 1997 under license agreement with Books24x7
