Using parallel resonators to create improved maximally flat quarter-wavelength transformer impedance-matching networks

Journal Article

This paper presents a general approach for designing maximally flat quarter-wave transformer impedance-matching networks (QWT-IMN's) used in conjunction with parallel resonators. The approach used finds a maximally flat form by setting lower order terms of the general form to zero. This general form is found using ABCD matrices [1]. The resulting maximally flat form is identical to the form for quarter-wavelength-coupled filters. Using parallel resonators improves QWT-IMN designs in three ways. First, adding parallel resonators to a QWT-IMN improves the poor stopband rejection from which QWT-IMN's suffer. Second, for a given load-to-source mismatch, a QWT-IMN has a fixed response, i.e., a fixed total Q. By using more than one parallel resonator, numerous response realizations, i.e., values of total Q, can be achieved for a given load-to-source mismatch. Third, using parallel resonators requires one less quarter-wave transformer to achieve the same order of response. © 1999 IEEE.

Full Text

Duke Authors

Cited Authors

  • Drozd, JM; Joines, WT

Published Date

  • 1999

Published In

Volume / Issue

  • 47 / 2

Start / End Page

  • 132 - 141

International Standard Serial Number (ISSN)

  • 0018-9480

Digital Object Identifier (DOI)

  • 10.1109/22.744287