IEMN: Multiport vector network analyzer configured in RF interferometric mode for reference impedance renormalization
IEMN published a peer-reviewed article "Multiport vector network analyzer configured in RF interferometric mode for reference impedance renormalization"
by HADDADI K., OKADA E., MUBARAK F., THERON D., DAMBRINE G.
Conference: 2019 IEEE/MTT-S International Microwave Symposium - IMS 2019
Abstract— A novel active microwave interferometric technique is implemented on a multiport vector network analyzer for renormalizing the reference impedance 50 Ohms into any desired complex impedance. The resulting measured reflection coefficient around the new reference impedance is around zero, resulting in high measurement sensitivity. The method proposed avoids any external component commonly found in interferometric set-ups. In addition, a zeroing process including vector calibration is developed for broad frequency range and requires only a software procedure to be implemented in the system framework.
Keywords— multiport vector network analyzer, microwave interferometry, extreme impedance, vector calibration.
QWED: Efficient Implementation of BOR FDTD Algorithms in the Engineering Design of Reflector Antennas
QWED presented a peer-reviewed article:
Efficient Implementation of BOR FDTD Algorithms in the Engineering Design of Reflector Antennas
Presented on 13th European Conference on Antennas and Propagation, EuCAP 2019, www.eucap2019.org, Krakow, Poland, March 31-April 5, 2019.
Marzena Olszewska-Placha, Christophe Granet, Malgorzata Celuch, Maciej Sypniewski
Abstract—This work presents a modelling-based methodology forthedesign and evaluation of axi-symmetrical antennas, including horns, compact and large dual-reflector antenna systems. The starting concept of the antenna is an educated guess stemming from the engineer’s experience; however, further evaluation and optimization of that concept continue in a computational loop that involves a conformal FDTD algorithm in a BOR formulation. Our BOR FDTD retains the advantages of general-purpose 3D FDTD software, providing full-wave solutions and delivering key engineering parameters of antenna systems together with an insight into the distribution of the electromagnetic near-field, a useful feature to assess the mismatch of thehorn due to the subreflector interaction.At the same time, the unique BOR formulation accelerates the analysis by orders in magnitude, making it practical to evaluate many designs within a manual or automatic optimization loop. We also show that BOR FDTD compares favourably with the Mode Matching Technique, being computationally fast while obviating the MMT inherent structural assumptions.
Index Terms—axi-symmetrical antenna, BOR, FDTD, dual-reflector antenna, horn antenna.
QWED: Advanced modelling-based methodology for evaluation and and design of large reflectors antennas for space applications state-of-the-art and collaborative research perspective
QWED presented a peer-reviewed article:
ADVANCED MODELLING-BASED METHODOLOGY FOREVALUATIONAND DESIGN OF LARGE REFLECTOR ANTENNAS FOR SPACE APPLICATIONS -STATE-OF-THE-ART AND COLLABORATIVE RESEARCH PERSPECTIVE
Wojciech Gwarek, Malgorzata Celuch, Marzena Olszewska–Placha
Presentation done during the 39th ESA Antenna Workshop of Multibeam and Reconfigurable Antennas for Space Applications, ESTEC, Nordwijk, NL, October, 2-5, 2018
Abstract–This workaims to popularise a modelling-based methodology for the design of antenna systems. Our in-house conformal FDTD algorithms in full 3D and BOR V2D formulations areamalgamated in the commercial QW-3D and QW-V2D packages, respectively. QW-V2D provides unique functionalities for the full-wavemodelling oflarge axisymmetrical dual-reflector as well as dual-mode antennas, scaling to over 3000wavelength. Applicationsof QW-3D to waveguide components of antenna feeds are illustrated with ALMA project memos and further extend to polarisers, diplexers, and OMTs. At the workshop we shall demonstrateco-and post-processing techniques, which produce keyengineering parameters but also allow direct insight into EM near-field distributions and thereby reveal otherwise invisible causes of, e.g., spillover.We also discuss applications of QW-V2D in material measurement techniques, with focus on our own dielectric resonator setups.
IEMN: Electromagnetic Modeling in Near-Field Scanning Microwave Microscopy
IEMN published a peer-reviewed article during NEMO 2018: "Electromagnetic Modeling in Near-Field Scanning Microwave Microscopy; Highlighting Limitations in Spatial and Electrical Resolutions"
by P. Polovodov, C. Brillard, O. C. Haenssler, C. Boyaval, D. Deresmes, S. Eliet, F. Wang, N. Clément, D. Théron, G. Dambrine and K. Haddadi (University Lille, CNRS, UMR 8520 - IEMN)
IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization, IEEE NEMO2018, nemo-ieee.org, Reykjavik Iceland, August 8-10, 2018
Special Session TA4 - Modeling and Design of Nanomaterials, Nanopackages, NanoDevices and Graphene; Proceedings of 5th IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization, IEEE NEMO2018.
Abstract—Near-field scanning microwave microscopy (NSMM) is a scanning probe microscopy (SPM) technique that measures the local interaction of evanescent microwaves with a sample using a sharp tip probe. The traceability in NSMM is still challenging as the distribution of the electrical fields is affected by several parameters. In this effort, finite element method (FEM) based electromagnetic modeling methods are used to study the effects of the wavelength of operation and the humidity on the spatial and electrical resolutions respectively. From the simulated data, it is demonstrated that the lateral resolution is improved with increasing the frequency of operation. Furthermore, the existence and influence of a water meniscus is highlighted by fine comparison between simulated and measured data. To face these issues, an alternative near-field scanning millimeter-wave microscopy working in a controlled environment is proposed.
Keywords— near-field scanning microwave microscopy (NSMM); finite element method (FEM); electromagnetic modeling; vector network analyzer (VNA); scanning electron microscope (SEM).
Keysight: Nanoscale dipole dynamics of protein membranes
Nanoscale dipole dynamics of protein membranes
Keysight's team (Georg Gramse, Andreas Schönhals and Ferry Kienberger) published a new paper titled "Nanoscale dipole dynamics of protein membranes".
The Royal Society of Chemistry, 2019.
Abstract - We investigate the nearﬁeld dipole mobility of protein membranes in a wide frequency range from 3 kHz to 10 GHz. The results of our nanoscale dielectric images and spectra of bacteriorhodopsin (bR) reveal Debye relaxations with time constants of τ ∼ 2 ns and τ ∼ 100 ns being characteristic of the dipole moments of the bR retinal and α-helices, respectively. However, the dipole mobility and therefore the protein biophysical function depend critically on the amount of surface water surrounding the protein, and the characteristic mobility in the secondary structure is only observed for humidity levels <30%. Our results have been achieved by adding the frequency as a second fundamental dimension to quantitative dielectric microscopy. The key elements for the success of this advanced technique are the employed heterodyne detection scheme, the broadband electrical signal source, a high frequency optimized cabling, development of calibration procedures and precise ﬁnite element modelling. Our study demonstrates the exciting possibilities of broadband dielectric microscopy for the investigation of dynamic processes in cell bioelectricity at the individual molecular level. Furthermore, the technique may shed light on local dynamic processes in related materials science applications like semiconductor research or nano-electronics.
The paper can be download here.
QWED: Accurate Analysis of Whispering Gallery Modes in Dielectric Resonators with BoR FDTD Method
Peer-reviewed article by Malgorzata Celuch and Wojciech Gwarek.
presentation done during the 22nd International Microwave and Radar Conference, MIKON-2018, Poznań, Poland, May 14-17, 2018
This paper presents an accurate approach to FDTD analysis of whispering gallery modes in dielectric resonators. In those problems resonant frequencies are supposed to be extracted with relative errors below 10-4. It is widely believed that only custom - made software codes, based on mode matching methods, can meet such stringent accuracy requirements. Herein, we demonstrate how the required accuracy can be obtained with a general - purpose FDTD code, run within a new three - step procedure. Advantages of the FDTD approach include more flexibility in modelling scenarios with unusual shapes or / and lossy materials.
Keywords—Dielectric resonators, whispering gallery modes, EM simulations, FDTD method, bodies of revlolution.
The paper can be download here.