Incorporation of feed-network and circuit modeling into the time-domain finite element analysis of antenna arrays and microwave circuits

Wang, Rui

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https://hdl.handle.net/2142/16536 Copy

Description

Title

Incorporation of feed-network and circuit modeling into the time-domain finite element analysis of antenna arrays and microwave circuits

Author(s)

Wang, Rui

Issue Date

2010-06-29T00:59:58Z

Director of Research (if dissertation) or Advisor (if thesis)

Jin, Jianming

Doctoral Committee Chair(s)

Jin, Jianming

Committee Member(s)

• Cangellaris, Andreas C.
• Feng, Milton
• Schutt-Ainé, José E.

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Time-domain finite element method
• antenna arrays
• domain decomposition
• feed-network modeling
• vector-fitting technique
• hybrid solver
• linear/nonlinear circuit simulation
• transient analysis
• admittance matrices
• multiport lumped networks
• recursive convolution
• full-wave analysis
• time marching
• tree-cotree splitting
• multi-rate simulation
• time-stepping scheme

Abstract

In this dissertation, accurate and efficient numerical algorithms are developed to incorporate the feed-network and circuit modeling into the time-domain finite element analysis of antenna arrays and microwave circuits. First, simulation of an antenna system requires accurate modeling of interactions between the radiating elements and the associated feeding network. In this work, a feed network is represented in terms of its scattering matrix in a rational function form in the frequency domain that enables its interfacing with the time-domain finite element modeling of the antenna elements through a fast recursive time-convolution algorithm. The exchange of information between the antenna elements and the feed network occurs through the incident and reflected modal voltages/currents at properly defined port interfaces. The proposed numerical scheme allows a full utilization of the advanced antenna simulation techniques, and significantly extends the current antenna modeling capability to the system level. Second, a hybrid field-circuit solver that combines the capabilities of the time-domain finite element method and a lumped circuit analysis is developed for accurate and efficient characterization of complicated microwave circuits that include both distributive and lumped-circuit components. The distributive portion of the device is modeled by the time-domain finite element method to generate a finite element subsystem, while the lumped circuits are analyzed by a SPICE-like circuit solver to generate a circuit subsystem. A global system for both the finite-element and circuit unknowns is established by combining the two subsystems through coupling matrices to model their interactions. For simulations of even more complicated mixed-scale circuit systems that contain pre-characterized blocks of discrete circuit elements, the hybrid field-circuit analysis implemented a systematic and efficient algorithm to incorporate multiport lumped networks in terms of frequency-dependent admittance matrices. Other advanced features in the hybrid field-circuit solver include application of the tree-cotree splitting algorithm and introduction of a flexible time-stepping scheme. Various numerical examples are presented to validate the implementation and demonstrate the accuracy, efficiency, and applications of the proposed numerical algorithms.

Graduation Semester

2010-5

Permalink

http://hdl.handle.net/2142/16536

Copyright and License Information

Copyright 2010 Rui Wang

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