Comparison of subspace and ARX models of a waveguide's terahertz transient response after optimal wavelet filtering

S. Hadjiloucas, R. K. H. Galvao, V. M. Becerra, J. W. Bowen, R. Martini, M. Brucherseifer, H. P. M. Pellemans, P. H. Bolivar, H. Kurz, J. M. Chamberlain

    Research output: Contribution to journalArticlepeer-review


    A quasi-optical deembedding technique for characterizing waveguides is demonstrated using wide-band time-resolved terahertz spectroscopy. A transfer function representation is adopted for the description of the signal in the input and output port of the waveguides. The time-domain responses were discretized and the waveguide transfer function was obtained through a parametric approach in the z-domain after describing the system with an AutoRegressive with eXogenous input (ARX), as well as with a state-space model. Prior to the identification procedure, filtering was performed in the wavelet domain to minimize both signal distortion, as well as the noise propagating in the ARX and subspace models. The optimal filtering procedure used in the wavelet domain for the recorded time-domain signatures is described in detail. The effect of filtering prior to the identification procedures is elucidated with the aid of pole-zero diagrams. Models derived from measurements of terahertz transients in a precision WR-8 waveguide adjustable short are presented.
    Original languageEnglish
    Pages (from-to)2409-2419
    Number of pages11
    JournalIEEE Transactions on Microwave Theory and Techniques
    Issue number10
    Publication statusPublished - 2004


    • identification algorithms, multimode waveguide characterization, signal, processing, terahertz spectroscopy, TIME-DOMAIN SPECTROSCOPY, IDENTIFICATION, SPACE


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