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Efficient estimation of adjoint‐variable S ‐parameter sensitivities with time domain TLM
Author(s) -
Bakr M. H.,
Nikolova N. K.
Publication year - 2005
Publication title -
international journal of numerical modelling: electronic networks, devices and fields
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.249
H-Index - 30
eISSN - 1099-1204
pISSN - 0894-3370
DOI - 10.1002/jnm.571
Subject(s) - classification of discontinuities , sensitivity (control systems) , transmission line , mathematics , time domain , estimation theory , port (circuit theory) , frequency band , transmission (telecommunications) , frequency domain , algorithm , computer science , mathematical analysis , electronic engineering , engineering , telecommunications , bandwidth (computing) , computer vision
We present a novel algorithm for efficient estimation of S ‐parameter sensitivities with the time‐domain transmission line modelling (TLM) method. The original electromagnetic structure is simulated using TLM to obtain the S ‐parameters in the desired frequency band. For each port, an adjoint TLM simulation that runs backward in time is derived and solved. The sensitivities of the S ‐parameters in the desired frequency band are estimated using only the original and adjoint simulations. For a structure with N p ports and n designable parameters, our approach requires only N p additional simulations regardless of n . This can be easily contrasted with the 2 nN p additional simulations required by the central difference approximation. Our algorithm is illustrated through the estimation of S ‐parameter sensitivities with respect to the dimensions of waveguide discontinuities. Very good match is obtained between our sensitivity estimates and those obtained using central difference approximation. Copyright © 2005 John Wiley & Sons, Ltd.