Uncertainty quantification of crosstalk using stochastic reduced order models

This paper introduces a novel statistical method, referred to as the stochastic reduced order model (SROM) method, to predict the variability of cable crosstalk subject to a range of parametric uncertainties. The SROM method is a new member of the family of stochastic approaches to quantify propagated uncertainty in the presence of multiple uncertainty sources. It is nonintrusive, accurate, efficient, and stable, thus could be a promising alternative to some well-established methods, such as the Stochastic Galerkin and stochastic collocation (SC) methods. In this paper, the SROM method is successfully applied to obtain the statistics of cable crosstalk subject to single and multiple uncertainty sources. The statistics of uncertain cable parameters is first accurately approximated by SROM, i.e., pairs of very few samples with known probabilities, such that the uncertain input space is well represented. Then, a deterministic solver is used to produce the samples of cable crosstalk with the corresponding probabilities, and finally the uncertainty propagated to the crosstalk is quantified with good accuracy. Compared to the conventional Monte-Carlo simulation, the statistics of crosstalk obtained by the SROM method converge much faster by orders of magnitude. Also, the computational cost of the SROM method is shown to be small and can be tuned flexibly depending on the accuracy requirement. The SC method based on tensor product sampling strategy is also implemented to validate the efficacy of the SROM method

Numerical Analysis of a Transmission Line Illuminated by a Random Plane-Wave Field Using Stochastic Reduced Order Models

A novel nonintrusive statistical approach, known as the stochastic reduced order model (SROM) method, is applied to efficiently estimate the statistical information of the terminal response (i.e., the induced current) in transmission lines excited by a random incident plane-wave field. The idea of the SROM method is conceptually simple, i.e., to represent the uncertain input space dimensioned by random variables using the SROM-based input model. This input model consists of a very small number of selected samples with assigned probabilities. Thus, only these input samples in the model need to be evaluated using the deterministic solver. The SROM-based output model can be constructed to approximate the propagated uncertainty to the real output response with elementary calculation. The efficiency and accuracy of the SROM method to obtain the statistics of the induced current are analyzed using two examples, where the complexity of the uncertain input space gradually increases. The performance of the SROM method is compared with that of the traditional Monte Carlo (MC) method. The stochastic collocation (SC) method based on sparse grid sampling strategy computed via the Smolyak algorithm is also implemented to fairly evaluate the SROM performance. The result shows that the SROM method is much more efficient than the MC method to obtain accurate statistics of the induced current, and even shows a faster convergence rate compared with that of the SC method in the examples considered. Therefore, the SROM method is a suitable approach to investigate the variability of radiated susceptibility in electromagnetic compatibility problems with a random incident wave

Advancements in RF, microwave and millimeter-wave circuits and devices

Microwave is a term used to describe electromagnetic (EM) waves with frequencies ranging from 300 MHz to 300 GHz. This frequency range corresponds to the free space wavelengths of 1 m to 1 mm respectively. EM waves with frequencies ranging from 30 GHz to 300 GHz are commonly known as millimetre-waves because their wavelengths fall above 1 mm and below 10 mm. The radio frequency (RF) spectrum lies below the microwave spectrum. However, the boundary between RF and microwave spectrums is arbitrary and depends on the technology developed for the exploitation of the specific spectrum

Truth of Chinese Survivors Concealed and Rediscovered From Titanic to The Six

Conventional film Titanic fooled the Chinese audience with an untold story of Chinese survivors through following narrative features of transitivity, identification, transparency, single diegesis, closure, and pleasure. Based on its skillfully designed narration strategy, the noble image of Anglo-Saxon gentlemen was well constructed. However, documentary film The Six pieced together the fragmented records of various sources and revealed the truth of what happened to those Chinese survivors through six corresponding narrative features by Peter Wollen, namely intransitivity, estrangement, foregrounding, multiple diegesis, aperture, and unpleasure. The unfair treatment Chinese survivors received added misfortunes to their sufferings in a huge tragic disaster in a foreign land. The images and characters of Chinese survivors reconstructed in The Six clear up what has been twisted and optionally forgotten.

Implementing the Global University Publications Licence: a new open scholarship model for advocating change

Universities want a voluntary, non-exclusive licence from authors to disseminate publications. This practitioner case study explores an innovative model to communicate and advance open and equitable scholarship through the implementation of the Global University Publications Licence at the University of Nottingham Ningbo China. This article explains the licensing policy and key influences, including, the copyright law of the People’s Republic of China and the Declaration on Research Assessment (DORA). The University approved the Global University Publications Licence, with implementation from 1 August 2019. It is available in Chinese and English. Since implementation, the University has retained rights for 74% of research publications submitted. 100% of those publications are available through the University with a CC-BY licence and zero embargo. The open scholarship model provides an equitable approach to versions and citation. The article concludes by suggesting university libraries can exploit copyright law in China to progress open scholarship strategies, including recognition of employers as authors of works, a priority right to the exploitation of works and an embargo protection of two years after the completion of the work. The author’s final version of publications can be open, discoverable, cited and preserved through trusted universities with global reputations for high-quality research

A Wide Dynamic Range Rectifier Based on HEMT Device with a Variable Self-Bias Voltage

This brief focuses on a highly efficient rectifier based on a high-electron-mobility transistor (HEMT) with a wide dynamic range of input power. Due to the nonlinear characteristics of HEMT, the impedance mismatch at different input power levels is a major challenge in rectifier design. Herein, a variable voltage gate self-bias network is proposed. It can dynamically generate a DC voltage according to the input power level, and continuously provide the optimal bias for the HEMT, thereby improving the RF to DC conversion efficiency in a wide input power range. This design does not require any external sensing or dynamic control circuit. The power needed by the self-bias network is provided using a weak coupling structure placed at the input port, which couples a small amount of the received RF power to operate the self-bias network. It is demonstrated that the proposed rectifier can achieve a dynamic operating power range of 24 dB (from 1 to 25 dBm) for over 60% conversion efficiency, or 16 dB for over 70% conversion efficiency in the measurement