Estimation of Q-factors and resonant frequencies

Coakley, Kevin J.; Splett, Jolene D.; Janezic, Michael D.; Kaiser, Raian F.

doi:10.1109/tmtt.2003.808578

Cited by 57 publications

(23 citation statements)

References 6 publications

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“…The complex transmission coefficients were then modeled as a damped driven harmonic oscillator [25]- [27]. Fitting enabled us to more accurately obtain the loaded damping ratio for tested materials and the empty cavity [25]- [27], which is essential to the accuracy of cavity perturbation technique.…”

Section: B Analysismentioning

confidence: 99%

Dielectric Characterization by Microwave Cavity Perturbation Corrected for Nonuniform Fields

Orloff

Obrzut

Long

et al. 2014

IEEE Trans. Microwave Theory Techn.

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Nonuniform fields decrease the accuracy of dielectric characterization by microwave cavity perturbation. These fields are due to the slot in the cavity through which the sample is inserted and the boundary between the sample and the metallic walls inside of the cavity. To address this problem, we measured the natural frequency and damping ratio of a resonant cavity as a sample is inserted into the rectangular cavity. We found that for a range of cavity filling fractions, a linear regression on the natural frequency and damping ratio versus the effective volume fraction of the sample in the cavity could be used to extract the complex permittivity of the sample. We verified our technique by measuring a known quartz substrate and comparing the results to finite-element simulations. When compared to the conventional technique, we found a significant improvement in the accuracy for our samples and measurement setup. We confirmed our technique on two lossy samples: a neat stoichiometric mixture bisphenol A epoxy resin and one containing a mass fraction of 3.5% multi-walled carbon nanotubes (MWCNTs). At the mode (7.31 GHz), the permittivity and loss tangent of the epoxy were measured to be and , respectively. The epoxy with a mass fraction of 3.5% MWCNTs had a permittivity of and loss tangent of .Index Terms-Bisphenol A epoxy, metrology, microwave, multi-walled carbon nanotubes (MWCNTs), nanocomposites, noncontact, nondestructive, resonator.

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Section: B Analysismentioning

confidence: 99%

Dielectric Characterization by Microwave Cavity Perturbation Corrected for Nonuniform Fields

Orloff

Obrzut

Long

et al. 2014

IEEE Trans. Microwave Theory Techn.

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“…Regression analysis from the data set revealed that linear regression was not a good estimation in calculating the uncertainty in . Since uncertainty of the measured quality factor is the major error source [18], if other uncertainties are neglected, such as resonant frequency, the uncertainty in can be calculated from the uncertainty in the measured . For these sets of measurements, a 10% uncertainty in measured was assumed [19].…”

Section: Rf Characterization Of Paper Substratementioning

confidence: 99%

RFID Tag and RF Structures on a Paper Substrate Using Inkjet-Printing Technology

Yang

Rida

Vyas

et al. 2007

IEEE Trans. Microwave Theory Techn.

589

318

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Abstract-In this paper, inkjet-printed UHF and microwave circuits fabricated on paper substrates are investigated for the first time as an approach that aims for a system-level solution for fast and ultra-low-cost mass production. First, the RF characteristics of the paper substrate are studied by using the microstrip ring resonator in order to characterize the relative permittivity ( ) and loss tangent (tan ) of the substrate at the UHF band for the first time reported. A UHF RFID tag module is then developed with the inkjet-printing technology, proving this approach could function as an enabling technology for much simpler and faster fabrication on/in paper. Simulation and well-agreed measurement results, which show very good agreement, verify a good performance of the tag module. In addition, the possibility of multilayer RF structures on a paper substrate is explored, and a multilayer patch resonator bandpass filter demonstrates the feasibility of ultra-low-cost 3-D paper-on-paper RF/wireless structures.

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“…[16][17][18][19][20] Petersan and Anlage 16 provided a comprehensive comparison between the different methods. The focus of this work, however, is to calculate the Q-factor based on the magnitude transfer characteristic of the resonator, i.e., based on the magnification factor ␤ described by Eq.…”

Section: B Common Methods In Extraction Of Q-factormentioning

confidence: 99%

An iterative curve fitting method for accurate calculation of quality factors in resonators

Naeli

Brand

2009

Review of Scientific Instruments

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A new method for eliminating the noise effect in interpreting the measured magnitude transfer characteristic of a resonator, in particular in extracting the Q-factor, is proposed and successfully tested. In this method the noise contribution to the measured power spectral density of resonator is iteratively excluded through a sequence of least-square curve fittings. The advantage of the presented method becomes more tangible when the signal to noise power ratio (SNR) is close to unity. A set of experiments for a resonant cantilever vibrating at different amplitudes has shown that when SNR is less than 10, the calculation results of conventional methods in extracting the Q-factor, i.e., the 3 dB bandwidth and single least-square curve fit, exhibit significant deviations from the actual Q-factor, while the result of the proposed iterative method remains in 5% margin of error even for a SNR of unity. This method is especially useful when no specific data is available about the measurement noise, except the assumption that the noise spectral density is constant over the measured bandwidth.

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Estimation of Q-factors and resonant frequencies

Cited by 57 publications

References 6 publications

Dielectric Characterization by Microwave Cavity Perturbation Corrected for Nonuniform Fields

Dielectric Characterization by Microwave Cavity Perturbation Corrected for Nonuniform Fields

RFID Tag and RF Structures on a Paper Substrate Using Inkjet-Printing Technology

An iterative curve fitting method for accurate calculation of quality factors in resonators

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