This article introduces a novel multiphysics modeling framework for the high-fidelity simulation of superconductors in microwave. The proposed approach integrates the time-dependent Ginzburg-Landau (TDGL) equations with full-field radio frequency (RF) finite element method (FEM) simulations to enable seamless coupling between superconducting physics and electromagnetic wave propagation. By relying on standard RF design tools and workflows, this methodology bridges fundamental superconducting phenomena with practical engineering applications, offering designers enhanced simulation accuracy without requiring specialized expertise in superconductor physics. Demonstrative implementations include a microstrip line and a microstrip coupled-line structure, where time-dependent insertion losses, mode impedances, and the dependence of Josephson junctions (JJs) on geometrical dimensions are analyzed. The presented examples relying on the implementation of this novel workflow in the COMSOL Multiphysics platform highlight its potential to predict power-dependent losses and critical thresholds dependence on geometry and temperature, providing crucial insights for the design of high-power RF systems. An extension of the study toward JJs within the same framework is presented, opening the way to fully coupled design methods for quantum sensors relying on both RF fields and Josephson effects. The compatibility of the model with commercial RF tools positions it as a powerful resource for advancing the development of superconducting technologies in microwave engineering.

This article details the design and manufacturing process of a compact module fed through a transition between a grounded coplanar waveguide (GCPW) input line and an air-filled (AF) waveguide integrated into the substrate. This waveguide feeds a micromachined horn antenna. The developed technology is based on the micromachining of an AF waveguide on a first substrate and a horn antenna on a second one. These two substrates are then assembled by a thermal diffusion process, which allows for creating an electrically conductive bonding interface. The novelty of this work relies in the use of this innovative technological process for the realization of millimeter-wave (mm-wave) subsystems. Furthermore, the developed technology enables the creation of high-performance components utilizing AF substrate integrated waveguides (AF-SIWs). This approach effectively addresses the challenges associated with transferring, integrating, and reducing costs often encountered in high-frequency systems development. The resulting device forms a highly integrated, low-cost, yet electrically performant mm-wave module entirely manufactured with a printed circuit board (PCB) process. The manufactured prototype operates at V-band, exhibiting a bandwidth of 3.1% and a maximum gain of 6.4 dBi.

This article presents a novel multiphysics modeling approach to achieve high fidelity modeling of superconductors applied to microwave, THz and quantum devices. The implementation aims to help designers improve the fidelity of the simulations of superconductor-based devices while retaining the standard tools used in RF design. Examples of implementations of a microstrip line and a microstrip coupled line are exposed, illustrating the intricate coupling of the superconductor physics and the full-field RF simulations by extracting time-dependent insertion loss and even/odd mode impedance, opening the way to new design methods for superconducting devices.

This paper presents the study, design, realization, and measurement of a hybrid module integrating printed circuit board (PCB) and waveguide structures. The proposed approach leverages the advantages of both technologies: the compact integration and cost-effectiveness of PCB-based circuits combined with the high electrical performance of waveguides. Waveguides structures were fabricated by using metallized plastic additive manufacturing, enabling complex geometries while maintaining low mass and costs. Detailed synthesis of two transitions between PCB and waveguide sections is provided, addressing impedance matching, mode conversion, and fabrication constraints. A careful attention was brought to the mechanical and mass aspects of the assembly to account for highly demanding environments, thus avoiding any screws in the fabrication process. The module is then designed and optimized through full-wave electromagnetic simulations, followed by prototype fabrication and experimental validation. Measured results demonstrate good electrical performances, confirming the relevancy of the proposed integration strategy. This work contributes to the development of efficient, compact and lightweight RF front-end modules for emerging microwave and millimeter-wave applications.

This manuscript presents a platform called SAMBA dedicated to RADAR measurements. The platform is a completely modular receiver. This allows to obtain datas related to any devices at a level system by considering differential measurements. Indeed, the Direction of Arrival can be directly obtained instead of measuring S-parameters or radiation pattern. Twenty-four Rx modules are available which allow the measurements of quite complex antennas. In this paper, the platform is described and an example of application on radome performances is proposed.

In this work a novel TE10-TE20 mode converter for rectangular waveguide (RW) is presented. The proposed structure is conceived as a device that can be inserted in an empty straight section of a RW to yield the desired mode conversion. The converter is formed by a single 'V' shaped two-dielectric compact solid that can be scaled according to the frequency of operation and to fit inside the targeted RW section. It is a very low-cost light structure easy to fabricate compared to conventional alternatives of mode converters. To demonstrate the advantages of the proposed design and show its performance, a RW TE10-TE20 mode converter has been designed, simulated and measured at a center frequency of 10.7 GHz in a WR-137. It has been implemented by using additive manufacturing techniques and two materials with different dielectric permittivity. Simulated results show a mode conversion efficiency higher than 85% for a frequency bandwidth between 10.1 GHz and 11.7 GHz, and a mode purity higher than 98% for a frequency range between 9.5 GHz and 11.6 GHz. Back-to-back conversion measurements performed using WR-90 to WR-137 adapters and two of the proposed converter designs, are used to demonstrate the response of the novel TE10-TE20 mode converter. Also, the measurement of the H-plane radiation pattern of a TE20 fed WR-137 aperture is provided to corroborate the good performance of the proposed mode converter. The comparison between these measurements and electromagnetic simulations are in good agreement and show a band of operation between 10.1 GHz and 11.1 GHz.

This chapter presents the application of planar microwave sensors based on coupled resonators for the detection of solute concentration in aqueous solutions. First, the dielectric and conductive properties of these solutions, based on broadband experimental measurements, are presented. Then, different aspects of the sensor design, as well as a sensor circuit model, are exposed. For this model, the theoretical response and the influence of the mutual and self-capacitances of the resonators on the sensitivity are studied. The last section presents two practical examples of sensors applied, respectively, to binary (water-glucose) and ternary (water-sucrose-sodium chloride) solutions.

This work presents a microwave resonant multi-parameter sensor devoted to the simultaneous extraction of three characteristics of a homogeneous solid sample: its dielectric permittivity, its loss tangent and its thickness. The device is composed of three coupled resonators in two different substrate boards, having the sample between the boards, in a sandwich configuration. Presence of the sample impacts the electrical response of the device, not only influencing resonators, but also by affecting inter-resonator couplings. A method to analyse the response of the device, allowing for the extraction of the desired characteristics of the sample is proposed, as well as an experimental calibration procedure. The model is built upon 990 simulations, calibrated with three reference-samples measurements and then tested over 18 experimental measurements, with good results, thereby validating the multi-parameter sensing approach.

In this work a novel TE10–TE20 mode converter for rectangular waveguide (RW) is presented. The proposed structure is conceived as a device that can be inserted in an empty straight section of a RW to yield the desired mode conversion. The converter is formed by a single ‘V’ shaped two-dielectric compact solid that can be scaled according to the frequency of operation and to fit inside the targeted RW section. It is a very low-cost light structure easy to fabricate compared to conventional alternatives of mode converters. To demonstrate the advantages of the proposed design and show its performance, a RW TE10–TE20 mode converter has been designed, simulated and measured at a center frequency of 10.7 GHz in a WR-137. It has been implemented by using additive manufacturing techniques and two materials with different dielectric permittivity. Simulated results show a mode conversion efficiency higher than 85% for a frequency bandwidth between 10.1 GHz and 11.7 GHz, and a mode purity higher than 98% for a frequency range between 9.5 GHz and 11.6 GHz. Back-to-back conversion measurements performed using WR-90 to WR-137 adapters and two of the proposed converter designs, are used to demonstrate the response of the novel TE10–TE20 mode converter. Also, the measurement of the H-plane radiation pattern of a TE20 fed WR-137 aperture is provided to corroborate the good performance of the proposed mode converter. The comparison between these measurements and electromagnetic simulations are in good agreement and show a band of operation between 10.1 GHz and 11.1 GHz.

This paper presents a global sensitivity analysis of a high-Q partially air-filled pedestal resonator integrated in a printed circuit board. Nonlinear partial-least-squares-based polynomial chaos expansion (NLPLS-based PCE) approach is used for the global sensitivity analysis. Using NLPLS-based PCE a surrogate model is constructed with a reduced dimensionality, which enhances the performance of the algorithm. A standard PCE surrogate model, with all the system parameters, is created from the reduced NLPLS-based PCE surrogate model. The statistical information needed to perform the sensitivity analysis, i.e., variance, is extracted from the standard PCE surrogate model. A variance-based global sensitivity analysis is performed on the PCE model, each system parameter's sensitivity is quantified as the partial influence on the total variance of the performance variable S11. The chosen manufacturing technology involves a three-stage process: micromachining of the cavity, metallization, and thermos-diffusion stacking. During the three stages several problems may occur that can have an influence on the performance of the resonator, such as shape and size variation, and misalignment. The system parameters are set up according to these most common problems. The results show that, of the 8 system parameters chosen to evaluate, the height of the cavity and pedestal are the most sensitive parameters.

Durante los últimos años, el desarrollo de sensores de concentración de glucosa a través de resonadores planares de microondas ha llamado la atención de una considerable parte de la comunidad científica. Tras mostrar algunos resultados prometedores, los sensores experimentales actuales se enfrentan a ciertos desafíos primordiales. Entre ellos, el más crítico parece ser la selectividad a la concentración de glucosa frente a las variaciones de las concentraciones de otros componentes o parámetros. En este artículo estudiamos la selectividad experimental de sensores basados en resonadores de microondas al medir disoluciones multicomponente. Evaluamos minuciosamente el funcionamiento de estos sensores al medir disoluciones de agua pura, NaCl, albúmina y glucosa, analizando el impacto de las variaciones simultáneas de las concentraciones de glucosa y albúmina. Los resultados muestran una clara influencia de la concentración de albúmina en las medidas de la concentración de glucosa, lo que apunta a una falta de selectividad para estos los sensores. Hemos modelado esta influencia, y a partir de ella proponemos estrategias para afrontar el desafío de la selectividad con este tipo de sensores.

This article presents the electromagnetic (EM) properties of sodium lactate (C3H5NaO3)/water mixtures in the dc-to-microwave frequencies range and its exploitation for sensing purposes. EM features of solutions are characterized and modeled, while underlying physical phenomenon are explained. Then, intrinsic properties of the sodium lactate molecule and its consequences upon aqueous solutions are exploited to monitor concentrations. The proposed sensor is based on a coupled-resonators principle and works around 7 GHz, it features ability to extract sodium lactate concentrations in aqueous solutions within the 0–4.2 mol.L−1 range with a relative error lower than 8% if the sample temperature is given. Indeed, in addition to the extraction of the sodium lactate concentration, the proposed sensor also features the ability to monitor, simultaneously, temperature of the sample within the 15 °C–35 °C range. This innovative bi-parameter (sodium-lactate concentration and temperature), radio frequency-based monitoring exhibits precisions better than 5.2% on the sodium lactate concentrations and 12% on the temperature when these parameters are simultaneously extracted.

A 3D-printed 3-port antenna for MIMO communications is proposed. Its design relies on the combination of a cavity and annular slot structure. Originality of this works relies not only on its compactness and the method to excite the different radiating modes while preserving isolation, but also on its light weight obtained thanks to additive manufacturing process. The fabricated 3-port antennas, working at 5 GHz exhibit a low mass (less than 10 grams) and show a good agreement between measured and simulated electrical results.

The development of glucose concentration sensors by means of microwave planar resonant technology is an active field attracting considerable attention from the scientific community. Although showing promising results, the current experimental sensors are facing some fundamental challenges. Among them, the most critical one seems to be the selectivity of glucose concentration against the variations of the concentrations of other components or parameters. In this article, we investigate the selectivity of microwave planar resonant sensors when measuring multicomponent solutions. Three sensors are involved, two of them having been designed looking for a more simplified system with a reduced size, and the third one has been specially developed to improve the sensitivity. The performance of these sensors is thoroughly assessed with a large set of measurements involving multicomponent solutions composed of pure water, NaCl, albumin at different concentrations and glucose at different concentrations. The impact of the simultaneous variations of the concentrations of glucose and albumin on the final measurements is analyzed, and the effective selectivity of the sensors is discussed. The results show a clear influence of the albumin concentration on the measurements of the glucose concentration, thereby pointing to a lack of selectivity for all sensors. This influence has been modeled, and strategies to manage this selectivity challenge are inferred.

This paper reports on dielectric properties of ternary mixtures involving sodium chloride (NaCl) and sucrose (C 12 H 22 O 11 ) dissolved into water (H 2 O). Broadband electromagnetic characterizations of such mixtures at various concentrations were performed, evidencing a dual behavior made of conductive effects at low frequencies and dipolar relaxation at microwave frequencies. Conductive and dielectric properties resulting from these both effects were integrated into predictive models for variations of Cole–Cole model parameters. Based upon this modelling, an innovative microwave-based sensor able to retrieve concentrations of both sodium chloride and sucrose in ternary aqueous solutions was introduced, designed, realized and assessed. The proposed sensor shows an error lower than 5.5% for concentration ranges of 0 to 154 mmol/L for sodium chloride and 0 to 877 mmol/L for sucrose.