IEEE Journal of Microwaves

After three and a half anxious years and countless hours of effort we have now received our Clarivate rankings and the news is good. The 2024 Journal Citation Report came out on June 20 and IEEE Journal of Microwaves received a journal impact factor (JIF) of 6.9, putting us 34th?of 354 journals in electrical engineering and?3rd?amongst journals in the Emerging Sources Citation Index (ESCI). Our Scopus Citescore was also received and lists us at 10.7. We look forward to sharing more JMW news upon the release of our July issue.

??Article spotlight: Over-the-Air Phase Noise Spectral Density Measurement for FMCW Radar Sensors This paper presents a method for measuring the power spectral density (PSD) of a radar system using frequency modulated continuous wave (FMCW) or chirp sequence (CS) transmitters. The technique uses over- the-air transmission and is successfully demonstrated in the 76–81 GHz automotive band. The PSD can be used to characterize the phase noise of an FMCW radar which can be a major limiting parameter in many systems. This paper is part of our October 2024 issue. ?? Read the full article here: https://lnkd.in/gJ-pP3nf ?? Topics covered in this article: FMCW, chirp sequence, phase noise, radar, radar sensor, phase noise measurement, automotive measurement system ?? Authors: Christoph Birkenhauer, Peter Tschapek, Martin Vossiek

??Article spotlight: A 79 GHz SiGe Doherty Power Amplifier Suitable for Next-Generation Automotive Radar This paper presents the design and realization of a Doherty power amplifier for car radar applications in the 76–81 GHz band. The Doherty amplifier has superior performance in situations where there is a high peak-to-average power ratio, which is the case when orthogonal frequency division multiplexing is employed, as in many present-day car radar systems. The group obtained a saturated output power of 17.2 dBm and a peak power-added efficiency of 11.6%, making it much higher performing than traditional amplifiers used for this application. This paper is part of our October 2024 issue. ?? Read the full article here: https://lnkd.in/gfa8_zvb? ?? Topics covered in this article: Doherty, power amplifier, automotive, W-Band, millimeter-wave (mm-wave), monolithic microwave integrated circuit (MMIC), SiGe ?? Authors: Jan Sch?pfel, Tobias T. Braun, Julia Hellwig, Holger Rücker, Nils Pohl

??Article spotlight: Proving the Feasibility of D-Band Single SiGe MMIC Vector Network Analyzer Extension Modules With Large System Dynamic Range In this paper, authors present an all SiGe MMIC-based vector network analyzer frequency extension module for 110–170 GHz. The extender heads are extremely compact, and the performance is excellent, with a dynamic range above 90 dB from 110 GHz to 151 GHz and full two-port measurement capability, including calibration. They also demonstrate magnitude stability of ±0.5 dB and phase stability of ±2 degrees over 1 hour. Compared to other reported SiGe-based VNA extension modules, the Ruhr instrument is the best performing in this frequency range and comes close to the standards set by much more expensive and bulky discrete component-based systems. This paper is part of our October 2024 issue. ?? Read the full article here: https://lnkd.in/g8nPrHFs? ?? Topics covered in this article: Coupler, directivity, D-band, reflectometer, vector network analyzer, VNA, extension module, dynamic range, SiGe, MMIC ?? Authors: Justin Romstadt, Lukas Dierkes, Stephan Hauptmeier, Tobias T. Braun, Hakan Papurcu, Jens Richter, Pascal Stadler, Ahmad Zaben, Klaus Aufinger, Jan Barowski, Nils Pohl

Our November newsletter is here! Read on for more information on the future of JMW. We are seeking suggestions and potential guest editors for our planned special issues on multi-disciplinary topics, similar to our Microwaves in Climate Change issue, that combine microwave engineering with other scientific ?elds, so be sure to get in touch with us if you're interested or have any suggestions!

??Article spotlight: On Forward and Backward Modes in 1D Periodic Bounded Structures This paper discusses the issue of identifying the forward/backward nature of modes in bounded one-dimensional periodic structures. This identification is based on the possibility of adequately and uniquely defining the phase velocity in these types of structure. The authors propose a general definition of phase velocity for one-dimensional scalar waves and show that, according to that general definition, the voltage and current waves in non-homogeneous lossless transmission lines with positive per-unit-length capacitance and inductance are necessarily forward waves. The authors analyze in detail the particular case of periodic transmission lines and question the conclusions about the forward/backward nature of their modal solutions that are traditionally drawn from inspection of Brillouin diagrams. Numerical results for the case of corrugated parallel-plate waveguides support the idea that all modes can be considered forward-like as long as a periodic transmission line model remains a sensible and reliable description of the problem. In more general scenarios, the authors show that an appropriate definition of the phase velocity can still be found for electromagnetic waves with at least one linearly polarized field and that they are also necessarily forward waves if they propagate through media with positive ε and μ parameters. Finally, the authors relate their discussion to the effective refractive index of periodic structures, highlighting that although its definition is not valid for a general periodic structure, it can be useful in many practical cases. This paper is part of our October 2024 issue. ?? Read the full article here: https://lnkd.in/gBGdwuec? ?? Topics covered in this article: Dispersion diagram, forward and backward modes, periodic structures ?? Authors: Oskar Zetterstr?m, Raúl Rodriguez-Berral, Francisco Mesa, Oscar Quevedo Teruel

??Article spotlight: Advanced Modeling of Circular Waveguide-Based Devices With Smooth Profiles Using Transformation Optics and Hierarchical Model Reduction In this paper, the authors present a complete full-wave analysis of circular waveguide structures. The technique was first derived by the same authors for rectangular structures, and this paper extends the analysis to circular guides with arbitrary contours and dielectric filling. The authors show that their analysis method is rigorous and meets all the boundary conditions. They also note that the method reduces the degrees of freedom (nodes) used in traditional finite element solutions by more than two orders of magnitude. They compare their technique to commercial electromagnetic simulator software and show excellent agreement. Plans are underway to generalize the method to arbitrary cross sections. This paper is part of our October 2024 issue. ?? Read the full article here: https://lnkd.in/g7WUVKJA? ?? Topics covered in this article: Circular waveguide, electromagnetic modeling, finite element method, modal analysis, model order reduction, transformation optics, waveguide analysis ?? Authors: Giacomo Giannetti, Stefano Selleri, Gian Guido Gentili, Ginés García Contreras, Juan Córcoles, Jorge A. Ruiz-Cruz

??Article spotlight: Ordinary and Extraordinary Permittivities of 4H SiC at Different Millimeter-Wave Frequencies, Temperatures, and Humidities This paper brings together some hitherto very precise measurements on the dielectric properties of silicon carbide and extends them across the entire millimeter-wave region from 57 to 330 GHz. The authors have made the most precise and thorough RF measurements to date of the very important hexagonal semiconductor 4H silicon carbide. They make their measurements using a high-precision open resonator and can measure very accurate (<0.1 %) values for ordinary and extraordinary propagation (ε⊥ and ε||). They also measure the loss tangent and the dielectric constant temperature coefficient as well as changes at varying humidity levels. The paper shows that 4H SiC, with a loss tangent, tan δ= 1 × 10?4, is lower than sapphire, the current standard for millimeter-wave low-loss substrates. This is likely to become a very well-cited paper for anyone working on high-power, high-temperature, millimeter-wave devices that will need to rely on SiC. This paper is part of our October 2024 issue. ?? Read the full article here: https://lnkd.in/gpMiJkTn? ?? Topics covered in this article: Dielectric constant, millimeter wave, substrate integrated waveguide, Fabry–Perot resonator, loss tangent, permittivity, silicon carbide ?? Authors: Tianze Li, Lei L., Xiaopeng Wang, James Hwang, Shana Yanagimoto, Yoshiyuki Yanagimoto

??Article spotlight: An Almost-All Digital Proximity Transceiver for Mars Surface Missions In this paper, authors present their new CLEVER (Compact Low-Energy Version of the Electra Radio) integrated low-power CMOS system-on-chip rendition of the Electra radio that can implement and replace larger and much more power-hungry proximity links for small planetary rovers, copters, or stationary instruments located on the surface. These surface stationed systems must be able to communicate locally and via orbital relay satellite links that can broadcast and receive signals directly from the Earth. The particular instrument described is intended for Mars surface applications and represents a major reduction in mass, power, and volume, by employing all digital CMOS circuitry (except for a single variable gain pre-amplifier). The transceiver works between 390 and 450 MHz (UHF band) and the CMOS system itself draws only 356mW. Separate low-noise and power amplifiers are needed for the Tx output and Rx input. Detailed design and characterization of all the system components are given, as well as overall instrument performance over a wide temperature range. This paper is part of our October 2024 issue. ?? Read the full article here: https://lnkd.in/gNEFsggY? ?? Topics covered in this article: Compact low-energy electra radio, digital-radio, Mars proximity link, CLEVER ?? Authors: Adrian Tang, emmanuel decrossas, Zaid Towfic, Andrew Daniel, Josh Miller, Carlos Villalpando, Nacer Chahat, Yanghyo Kim

??Article spotlight: A Radar-Based Concept for Simultaneous High-Resolution Imaging and Pixel-Wise Velocity Analysis for Tracking Human Motion In this paper, the authors introduce an exciting new motion tracking concept that greatly improves on the accuracy and resolution of existing Doppler and range methods. They utilize a near-field back projection technique that displays successive images and compares phase changes on a pixel-by-pixel comparison. They first derive the new method and then demonstrate its efficacy by tracking human hand motions with a radial position accuracy of better than 1.5mm (mean absolute error). The instrument they use for their demonstration is based on an 80 GHz MIMO radar system with 94 Tx and 94 Rx modules arranged in two perpendicular lines and used in the near field. Range processing algorithms have to be significantly modified in the near field regime and so far, the method only attempts to track axial motion. However, the technique described is foundational and may be applied to the more general problem of tracking precise motion and speed in both axial and lateral coordinates and over large surfaces requiring significant angular span and high angular resolution. This paper is part of our October 2024 issue. ?? Read the full article here: https://lnkd.in/g7-Pwf7c? ?? Topics covered in this article: Human motion tracking, near-field imaging, radar imaging, velocity measurement ?? Authors: Johanna Br?unig, Simon Heinrich, Birte Coppers, Christoph Kammel, Vanessa Wirth, Marc Stamminger, Sigrid Leyendecker, Anna-Maria Liphardt, Ingrid Ullmann, Martin Vossiek