Freguency-domain analysis of nonlinear microwave circuits: Dissertation

Tapani Närhi

Research output: ThesisDissertationMonograph


A frequency-domain method is presented for the numerical steady-state analysis of nonlinear microwave circuits. Nonlinear elements are described with Chebyshev expansions or rational functions of Chebyshev expansions and their response is calculated directly in the frequency domain. Since no time-to-frequency conversions are needed, the method is especially suitable for multi-tone problems which are difficult to solve with harmonic-balance methods. Numerically stable recursive procedures allow the use of high-degree expansions for strongly nonlinear devices. The analysis method is coupled with a new measurement-based modelling approach, where the frequency-domain large-signal model is directly constructed through integration from the measured small-signal y-parameters. The resulting model is inherently consistent and allows an accurate representation of the frequency-dependent characteristics of nonlinear devices. The analysis method and modelling approach are experimentally verified by two- and three-tone measurements on a MESFET mixer.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Helsinki University of Technology
Award date9 Jul 1993
Place of PublicationEspoo
Print ISBNs951-38-4386-6
Publication statusPublished - 1993
MoE publication typeG4 Doctoral dissertation (monograph)


  • telecommunications
  • microwave devices
  • nonlinear systems
  • numerical analysis


Dive into the research topics of 'Freguency-domain analysis of nonlinear microwave circuits: Dissertation'. Together they form a unique fingerprint.

Cite this