The Intrinsic Impedance and Its Application to Backward and Forward Coupled-Line Couplers

Author

Mextorf, Henning ; Knochel, Reinhard

Author_Institution

Microwave Group, Univ. of Kiel, Kiel, Germany

Volume

62

Issue

2

fYear

2014

fDate

Feb. 2014

Firstpage

224

Lastpage

233

Abstract

The even-odd-analysis of a reciprocal and twofold symmetrical four-port provides four eigenimpedances. A method for the derivation of the intrinsic impedance of the network from these eigenimpedances is shown. Once the conjugate complex of its intrinsic impedance is presented to the external ports of the network, it will be a quadrature coupler. The usefulness of the intrinsic impedance is shown exemplarily by two detailed examples: the improvement of the directivity of microstrip coupled-line couplers and the development of forward coupled-line couplers. Approaches for the broadening of the bandwidth are shown. All couplers presented achieve superior performance regarding directivity, return loss, and bandwidth.

Keywords

eigenvalues and eigenfunctions; microstrip couplers; microstrip lines; backward coupled-line couplers; directivity improvement; eigenimpedances; even-odd-analysis; external ports; forward coupled-line couplers; intrinsic impedance; microstrip coupled-line couplers; quadrature coupler; reciprocal four-port; return loss; twofold symmetrical four-port; Couplings; Directional couplers; Equations; Impedance; Mathematical model; Ports (Computers); Coupled-line directional coupler; directional coupler; equivalent impedance; intrinsic impedance; proximity coupler;

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/TMTT.2013.2294853

Filename

6698397