Abstract:
Temporal late-time reflection and transmission natural mode amplitudes ( A_{n} , B_{n} , R_{n} , and Q_{n} ) of an {N} -layer multilayer structure are exami...Show MoreMetadata
Abstract:
Temporal late-time reflection and transmission natural mode amplitudes ( A_{n} , B_{n} , R_{n} , and Q_{n} ) of an {N} -layer multilayer structure are examined by separating the whole structure into left and right regions and middle layer. Due to this separation, some relations among these amplitudes are analytically disclosed. It is shown that if the structure has reflection symmetry, then the relation between A_{n} and B_{n} (and R_{n} and Q_{n} ) is in the form A_{n} = (-1)^{n-1} B_{n} (and R_{n} = (-1)^{n-1} Q_{n} ), where n is the mode number. These relationships are independent of material properties. A practical example related to damage or defect detection is considered to show the usefulness of these simple relations. The effect of noise on this detection was examined by introducing a Gaussian white noise (with a signal-to-noise ratio (SNR) ranging from 40, 30, and 20 dB to 10 dB) to the scattering parameters. It is observed that our proposed formalism is resistant to noise when detecting material defects or damages in reflection-symmetric multilayer structures. The effectiveness and feasibility of the derived objective function for a reflection-symmetric multiliayer structure were validated by coaxial line spectral (up to 26.5 GHz) and time-domain (via transformation) measurements of a three-layer structure.
Published in: IEEE Transactions on Instrumentation and Measurement ( Volume: 73)