Mixed-Mode Impedance and Reflection Coefficient of Two-Port Devices

Carrasco, Tomás; Sieiro, J.; López-Villegas, J.M.; Vidal, N.; Gonzalez-Echevarria, R.; Roca, E.

doi:10.2528/pier12052906

Cited by 19 publications

(14 citation statements)

References 20 publications

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“…To convert the two‐port scattering parameters of the inductor to Z eq , there exist different alternatives that correspond to how the device is excited from a source. [ 65 ] In this work, the differential impedance Z diff was chosen, which is associated with the impedance seen by a current source differential excitation. From the scattering parameters, the actual value of Z diff is given by

Z_{diff} = 2 Z_{0} \frac{1 + {normalΓ}_{diff}}{1 - {normalΓ}_{diff}}

where Z 0 is the characteristic impedance of the measurement system, i.e., 50 Ω, and Γ diff is given by the next combination of the scattering parameters

{normalΓ}_{diff} = \frac{1}{2} (S_{11} + S_{22} - S_{21} - S_{12})

where S ij corresponds to each one of the components in the scattering matrix, and which relates the input and output signals in the measurement.…”

Section: Resultsmentioning

confidence: 99%

Laser‐Induced Forward Transfer: A Digital Approach for Printing Devices on Regular Paper

Sopeña

Sieiro

Fernández-Pradas

et al. 2020

Adv Materials Technologies

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Inkjet printing (IJP) is the most widespread direct‐write technique in paper electronics. However, this technique cannot be used for printing devices on untreated regular paper, since its low‐viscosity nanoinks leak through the cellulose fibers. Thus, a planarization coating is frequently used as a barrier, even though this makes substrates more expensive and less eco‐friendly. Alternatively, high solid content screen printing (SP) inks could allow printing on regular paper due to their high viscosity and large particle size; however, they cannot be printed through IJP. Another digital technique is then required: laser‐induced forward transfer (LIFT). This work aims at proving the feasibility of LIFT for printing devices on regular paper. The main transfer parameters are systematically varied to obtain uniform Ag‐SP interconnects, whose performance is improved by a multiple‐printing approach. It results in low resistances with much better performance than those typical of IJP. After optimizing the functionality of the printed lines, a proof‐of‐concept consisting of a radio‐frequency inductor is provided. The characterization of the device shows a substantially higher performance than that of the same device printed with IJP ink in similar conditions, which proves the potential of LIFT for digitally fabricating devices on regular paper.

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Z_{diff} = 2 Z_{0} \frac{1 + {normalΓ}_{diff}}{1 - {normalΓ}_{diff}}

where Z 0 is the characteristic impedance of the measurement system, i.e., 50 Ω, and Γ diff is given by the next combination of the scattering parameters

{normalΓ}_{diff} = \frac{1}{2} (S_{11} + S_{22} - S_{21} - S_{12})

where S ij corresponds to each one of the components in the scattering matrix, and which relates the input and output signals in the measurement.…”

Section: Resultsmentioning

confidence: 99%

Laser‐Induced Forward Transfer: A Digital Approach for Printing Devices on Regular Paper

Sopeña

Sieiro

Fernández-Pradas

et al. 2020

Adv Materials Technologies

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“…where f is the frequency and eq Z is the equivalent input impedance. The equivalent input impedance can be easily obtained from the scattering parameters of the two-port structure representation of the inductor [15]. In Fig.…”

Section: Problem Formulationmentioning

confidence: 99%

Radio-frequency inductor synthesis using evolutionary computation and Gaussian-process surrogate modeling

Passos

Roca

Castro-López

et al. 2017

Applied Soft Computing

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In recent years, the application of evolutionary computation techniques to electronic circuit design problems, ranging from digital to analog and radiofrequency circuits, has received increasing attention. The level of maturity runs inversely to the complexity of the design task, less complex in digital circuits, higher in analog ones and still higher in radiofrequency circuits. Radiofrequency inductors are key culprits of such complexity. Their key performance parameters are inductance and quality factors, both a function of the frequency. The inductor optimization requires knowledge of such parameters at a few representative frequencies. Most common approaches for optimization-based radiofrequency circuit design use analytical models for the inductors. Although a lot of effort has been devoted to improve the accuracy of such analytical models, errors in inductance and quality factor in the range of 5% to 25% are usual and it may go as high as 200% for some device sizes. When the analytical models are used in optimization-based circuit design approaches, these errors lead to suboptimal results, or, worse, to a disastrous non-fulfilment of specifications. Expert inductor designers rely on iterative evaluations with electromagnetic simulators, which, properly configured, are able to yield a highly accurate performance evaluation. Unfortunately, electromagnetic simulations typically take from some tens of seconds to a few hours, hampering their coupling to evolutionary computation algorithms. Therefore, analytical models and electromagnetic simulation represent extreme cases of the accuracy-efficiency trade-off in performance evaluation of radiofrequency inductors. Surrogate modeling strategies arise as promising candidates to improve such trade-off. However, obtaining the necessary accuracy is not that easy as inductance and quality factor at some representative frequencies must be obtained and both performances change abruptly around the self-resonance frequency, which is particular to each device and may be located above or below the frequencies of interest. Both, offline and online training methods will be considered in this work and a new two-step strategy for inductor modeling is proposed that significantly improves the accuracy of offline methods. The new strategy is demonstrated and compared for both, singleobjective and multi-objective optimization scenarios. Numerous experimental results show that the proposed two-step approach outperforms simpler application strategies of surrogate modelling techniques, getting comparable performances to approaches based on electromagnetic simulation but with orders of magnitude less computational effort.

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“…where ƒ is the frequency and Z eq is the equivalent input impedance. The equivalent input impedance can be easily obtained from the S-parameters of the two-port structure representation of the inductor [10]. In Fig.…”

Section: Modeling Strategymentioning

confidence: 99%

An inductor modeling and optimization toolbox for RF circuit design

et al. 2017

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This paper describes the SIDe-O toolbox and the support it can provide to the radio-frequency designer. SIDe-O is a computer-aided design toolbox developed for the design of integrated inductors based on surrogate modeling techniques and the usage of evolutionary optimization algorithms. The models used feature less than 1% error when compared to electromagnetic simulations while reducing the simulation time by several orders of magnitude. Furthermore, the tool allows the creation of S-parameter files that accurately describe the behavior of inductors for a given range of frequencies, which can later be used in SPICE-like simulations for circuit design in commercial environments. This toolbox provides a solution to the problem of accurately and efficiently optimizing inductors, which alleviates the bottleneck that these devices represent in the radio-frequency circuit design process.

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Mixed-Mode Impedance and Reflection Coefficient of Two-Port Devices

Cited by 19 publications

References 20 publications

Laser‐Induced Forward Transfer: A Digital Approach for Printing Devices on Regular Paper

Laser‐Induced Forward Transfer: A Digital Approach for Printing Devices on Regular Paper

Radio-frequency inductor synthesis using evolutionary computation and Gaussian-process surrogate modeling

An inductor modeling and optimization toolbox for RF circuit design

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