Pub Date : 2024-10-11DOI: 10.1109/JMW.2024.3465868
Peter H. Siegel
This is our last release in 2024 and closes off our fourth year of publications. As we enter 2025, we will be scheduled for bimonthly, rather than quarterly, issues as we take advantage of a significant increase in paper submissions after receiving our Clarivate Journal Impact Factor of 6.9. Our October issue contains 14 regular papers and one invited review article on GaN MMIC's. As an added treat in 2024, immediately following the release of our regular issue papers, we will bring you our long-awaited special issue on Microwaves in Climate Change which we have been assembling since the start of 2024. IEEE Journal of Microwaves is extremely pleased to host this special topic, which was inspired by our special editorial series article, “ Making Waves: Microwaves in Climate Change,” (Siegel and Siegel 2023) that we released in July 2023. We hope that this special issue will bring additional scientists into the microwave publishing community and inspire more microwave engineers to seek out geophysicists, Earth scientists, environmentalists, climatologists, geochemical engineers, energy and power specialists, resource managers, and other technical experts who might benefit from the instrumentation, knowledge, and skillsets within our community. A more detailed introduction to the Climate Issue can be found in (Siegel 2024).
{"title":"Introduction to the Fall 2024 Issue","authors":"Peter H. Siegel","doi":"10.1109/JMW.2024.3465868","DOIUrl":"https://doi.org/10.1109/JMW.2024.3465868","url":null,"abstract":"This is our last release in 2024 and closes off our fourth year of publications. As we enter 2025, we will be scheduled for bimonthly, rather than quarterly, issues as we take advantage of a significant increase in paper submissions after receiving our Clarivate Journal Impact Factor of 6.9. Our October issue contains 14 regular papers and one invited review article on GaN MMIC's. As an added treat in 2024, immediately following the release of our regular issue papers, we will bring you our long-awaited special issue on \u0000<italic>Microwaves in Climate Change</i>\u0000 which we have been assembling since the start of 2024. \u0000<sc>IEEE Journal of Microwaves</small>\u0000 is extremely pleased to host this special topic, which was inspired by our special editorial series article, “\u0000<italic>Making Waves: Microwaves in Climate Change,”</i>\u0000 (Siegel and Siegel 2023) that we released in July 2023. We hope that this special issue will bring additional scientists into the microwave publishing community and inspire more microwave engineers to seek out geophysicists, Earth scientists, environmentalists, climatologists, geochemical engineers, energy and power specialists, resource managers, and other technical experts who might benefit from the instrumentation, knowledge, and skillsets within our community. A more detailed introduction to the Climate Issue can be found in (Siegel 2024).","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 4","pages":"583-593"},"PeriodicalIF":6.9,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10714377","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142408818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-11DOI: 10.1109/JMW.2024.3471803
Christoph Birkenhauer;Peter Tschapek;Martin Vossiek
Phase noise significantly degrades the performance of frequency-modulated continuous wave (FMCW)- and chirp sequence (CS)-based radar sensors. Knowledge of the power spectral density (PSD) of these sensors is therefore essential for estimating their limitations. This work presents a test setup where over-the-air (OTA) tests can be carried out and the PSD extracted directly from the signal radiated from a radar sensor operating in the $76 ,mathrm{G}mathrm{Hz}$ – $81 ,mathrm{G}mathrm{Hz}$ automotive frequency band. For this, the radar signal is demodulated in the analog domain by mixing it with a delayed version of the received signal. Demodulation compresses the signal bandwidth, simplifying hardware requirements for sampling and signal processing. The remaining systematic errors are compensated and the range correlation effect is corrected by an appropriate signal processing scheme. Our approach eliminates the need for prior knowledge of modulation parameters, leading to both increased precision and reduced potential for errors. The proposed setup is validated comparing system measurements with data obtained from established testing methods and simulations.The presented setup successfully demonstrates the capability of performing OTA test measurements of a PSD from a FMCW sensor. Our results demonstrate good agreement between the PSD test results and the expected outcome.
{"title":"Over-the-Air Phase Noise Spectral Density Measurement for FMCW Radar Sensors","authors":"Christoph Birkenhauer;Peter Tschapek;Martin Vossiek","doi":"10.1109/JMW.2024.3471803","DOIUrl":"https://doi.org/10.1109/JMW.2024.3471803","url":null,"abstract":"Phase noise significantly degrades the performance of frequency-modulated continuous wave (FMCW)- and chirp sequence (CS)-based radar sensors. Knowledge of the power spectral density (PSD) of these sensors is therefore essential for estimating their limitations. This work presents a test setup where over-the-air (OTA) tests can be carried out and the PSD extracted directly from the signal radiated from a radar sensor operating in the \u0000<inline-formula><tex-math>$76 ,mathrm{G}mathrm{Hz}$</tex-math></inline-formula>\u0000–\u0000<inline-formula><tex-math>$81 ,mathrm{G}mathrm{Hz}$</tex-math></inline-formula>\u0000 automotive frequency band. For this, the radar signal is demodulated in the analog domain by mixing it with a delayed version of the received signal. Demodulation compresses the signal bandwidth, simplifying hardware requirements for sampling and signal processing. The remaining systematic errors are compensated and the range correlation effect is corrected by an appropriate signal processing scheme. Our approach eliminates the need for prior knowledge of modulation parameters, leading to both increased precision and reduced potential for errors. The proposed setup is validated comparing system measurements with data obtained from established testing methods and simulations.The presented setup successfully demonstrates the capability of performing OTA test measurements of a PSD from a FMCW sensor. Our results demonstrate good agreement between the PSD test results and the expected outcome.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 4","pages":"733-741"},"PeriodicalIF":6.9,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10714376","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142408821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-11DOI: 10.1109/JMW.2024.3467937
{"title":"IEEE Journal of Microwaves Table of Contents","authors":"","doi":"10.1109/JMW.2024.3467937","DOIUrl":"https://doi.org/10.1109/JMW.2024.3467937","url":null,"abstract":"","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 4","pages":"C4-C4"},"PeriodicalIF":6.9,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10714390","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142409034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-11DOI: 10.1109/JMW.2024.3467931
{"title":"IEEE Journal of Microwaves Information for Authors","authors":"","doi":"10.1109/JMW.2024.3467931","DOIUrl":"https://doi.org/10.1109/JMW.2024.3467931","url":null,"abstract":"","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 4","pages":"C3-C3"},"PeriodicalIF":6.9,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10714448","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142408878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-11DOI: 10.1109/JMW.2024.3467935
{"title":"IEEE Microwave Theory and Technology Society Information","authors":"","doi":"10.1109/JMW.2024.3467935","DOIUrl":"https://doi.org/10.1109/JMW.2024.3467935","url":null,"abstract":"","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 4","pages":"C2-C2"},"PeriodicalIF":6.9,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10714391","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142408819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The radar-based analysis of human motion is actively being researched due to its contact- and markerless nature and ability to measure motion directly via the Doppler effect. Especially in medical and biomechanical fields, precise movement analysis is crucial. However, existing radar-based studies typically exhibit low lateral resolution, focusing on velocity evaluations and the tracking of scattering centers resolvable in the range or Doppler domains. In this work, we present a novel concept that enables a pixel-wise velocity analysis of human motion in radar near-field imaging scenarios. For this, we utilize the well-established back-projection technique to reconstruct consecutive radar images and perform a subsequent pixel-wise phase comparison. To accurately capture pixel-specific velocities along the depth dimension, this is followed by corrections of near-field geometry distortions accounting for aperture properties and pixel positions. Our theoretical derivations are supported by comprehensive point target simulations. To assess the performance of the proposed approach, we conducted a proof-of-concept study. We tracked a hand surface's movement while performing a finger tapping motion and compared the fingertip position and velocity determined by the radar with the respective values obtained from an optical marker-based system. The results showed a velocity measurement accuracy of $8.1 ,mathrm{mms}^{-1}$ and a tracking accuracy of $1.4 ,mathrm{m}mathrm{m}$ , demonstrating the great potential of our approach. The high angular resolution of the velocity measurement enables the tracking of the entire illuminated body shell, extending the range of future applications of radar-based motion analysis.
{"title":"A Radar-Based Concept for Simultaneous High-Resolution Imaging and Pixel-Wise Velocity Analysis for Tracking Human Motion","authors":"Johanna Bräunig;Simon Heinrich;Birte Coppers;Christoph Kammel;Vanessa Wirth;Marc Stamminger;Sigrid Leyendecker;Anna-Maria Liphardt;Ingrid Ullmann;Martin Vossiek","doi":"10.1109/JMW.2024.3453570","DOIUrl":"https://doi.org/10.1109/JMW.2024.3453570","url":null,"abstract":"The radar-based analysis of human motion is actively being researched due to its contact- and markerless nature and ability to measure motion directly via the Doppler effect. Especially in medical and biomechanical fields, precise movement analysis is crucial. However, existing radar-based studies typically exhibit low lateral resolution, focusing on velocity evaluations and the tracking of scattering centers resolvable in the range or Doppler domains. In this work, we present a novel concept that enables a pixel-wise velocity analysis of human motion in radar near-field imaging scenarios. For this, we utilize the well-established back-projection technique to reconstruct consecutive radar images and perform a subsequent pixel-wise phase comparison. To accurately capture pixel-specific velocities along the depth dimension, this is followed by corrections of near-field geometry distortions accounting for aperture properties and pixel positions. Our theoretical derivations are supported by comprehensive point target simulations. To assess the performance of the proposed approach, we conducted a proof-of-concept study. We tracked a hand surface's movement while performing a finger tapping motion and compared the fingertip position and velocity determined by the radar with the respective values obtained from an optical marker-based system. The results showed a velocity measurement accuracy of \u0000<inline-formula><tex-math>$8.1 ,mathrm{mms}^{-1}$</tex-math></inline-formula>\u0000 and a tracking accuracy of \u0000<inline-formula><tex-math>$1.4 ,mathrm{m}mathrm{m}$</tex-math></inline-formula>\u0000, demonstrating the great potential of our approach. The high angular resolution of the velocity measurement enables the tracking of the entire illuminated body shell, extending the range of future applications of radar-based motion analysis.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 4","pages":"639-652"},"PeriodicalIF":6.9,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10706625","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142408879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1109/JMW.2024.3454563
Giacomo Giannetti;Stefano Selleri;Gian Guido Gentili;Gines Garcia-Contreras;Juan Córcoles;Jorge A. Ruiz-Cruz
A powerful and accurate analysis method for the full-wave analysis of circular waveguide-based devices is introduced. The method uses transformation optics, hierarchical model reduction, and the finite element method. First, transformation optics is applied to map the original device in a cylinder filled with an anisotropic and inhomogeneous medium. Second, exploiting a hierarchical model reduction approach, the electric field is expanded in terms of the modes of the circular waveguide in the transverse plane, while the longitudinal dependence of the fields is tackled by a 1D finite element method. The BCs are fulfilled rigorously. The 3D integrals arising from the discretization of the vector electric field equation are separable, thus allowing for solving radial and longitudinal integrals once and for all, while the angular integrals are the only ones to be computed for each specific device geometry. The limitations of the method are: (a) the input and output waveguides must be circular waveguides, even with different radii; (b) the device lateral surface must be expressed as a strictly-positive single-valued function in cylindrical coordinates; (c) the device profile must be smooth. The method is verified against full-wave simulations from commercial software and measurements available in the literature, showing good agreement and efficiency.
{"title":"Advanced Modeling of Circular Waveguide-Based Devices With Smooth Profiles Using Transformation Optics and Hierarchical Model Reduction","authors":"Giacomo Giannetti;Stefano Selleri;Gian Guido Gentili;Gines Garcia-Contreras;Juan Córcoles;Jorge A. Ruiz-Cruz","doi":"10.1109/JMW.2024.3454563","DOIUrl":"https://doi.org/10.1109/JMW.2024.3454563","url":null,"abstract":"A powerful and accurate analysis method for the full-wave analysis of circular waveguide-based devices is introduced. The method uses transformation optics, hierarchical model reduction, and the finite element method. First, transformation optics is applied to map the original device in a cylinder filled with an anisotropic and inhomogeneous medium. Second, exploiting a hierarchical model reduction approach, the electric field is expanded in terms of the modes of the circular waveguide in the transverse plane, while the longitudinal dependence of the fields is tackled by a 1D finite element method. The BCs are fulfilled rigorously. The 3D integrals arising from the discretization of the vector electric field equation are separable, thus allowing for solving radial and longitudinal integrals once and for all, while the angular integrals are the only ones to be computed for each specific device geometry. The limitations of the method are: (a) the input and output waveguides must be circular waveguides, even with different radii; (b) the device lateral surface must be expressed as a strictly-positive single-valued function in cylindrical coordinates; (c) the device profile must be smooth. The method is verified against full-wave simulations from commercial software and measurements available in the literature, showing good agreement and efficiency.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 4","pages":"675-689"},"PeriodicalIF":6.9,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10706872","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142408731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1109/JMW.2024.3451056
Oskar Zetterstrom;Raúl Rodriguez-Berral;Francisco Mesa;Oscar Quevedo-Teruel
We discuss 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. We 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 nonhomogeneous lossless transmission lines with positive per-unit-length capacitance and inductance are necessarily forward waves. We 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 the inspection of the 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, we 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 $varepsilon$ and $mu$ parameters. Finally, we relate our 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.
{"title":"On Forward and Backward Modes in 1D Periodic Bounded Structures","authors":"Oskar Zetterstrom;Raúl Rodriguez-Berral;Francisco Mesa;Oscar Quevedo-Teruel","doi":"10.1109/JMW.2024.3451056","DOIUrl":"https://doi.org/10.1109/JMW.2024.3451056","url":null,"abstract":"We discuss 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. We 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 nonhomogeneous lossless transmission lines with positive per-unit-length capacitance and inductance are necessarily forward waves. We 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 the inspection of the 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, we 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 \u0000<inline-formula><tex-math>$varepsilon$</tex-math></inline-formula>\u0000 and \u0000<inline-formula><tex-math>$mu$</tex-math></inline-formula>\u0000 parameters. Finally, we relate our 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.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 4","pages":"690-705"},"PeriodicalIF":6.9,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10706633","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142408840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A novel D-band self-packaged silicon-based air cavity-backed transition from grounded coplanar waveguide to air-filled rectangular waveguide was investigated, fabricated, and measured in this work. The equivalent circuit model was established and analyzed in detail, and design procedures are given. The calculated, simulated, and measured S-parameters of the transition show some agreement. The minimum measured insertion loss of the proposed transition is 1.1 dB at 147 GHz with a fractional 3-dB bandwidth of 10.2%. This transition demonstrates outstanding performance of low loss and profile compared with state-of-the art works in our in-house silicon-based MEMS photosensitive composite film fabrication process. It can be further used in a high-performance joint radar communication system in packaging.
在这项工作中，研究、制造和测量了一种新型 D 波段自封装硅基气腔从接地共面波导到充气矩形波导的过渡。建立并详细分析了等效电路模型，并给出了设计步骤。过渡的计算、模拟和测量 S 参数显示出一定的一致性。在 147 GHz 频率下，拟议过渡器的最小测量插入损耗为 1.1 dB，3 dB 分数带宽为 10.2%。与我们内部的硅基 MEMS 光敏复合膜制造工艺中的先进产品相比，这种过渡器具有低损耗和低剖面的出色性能。它可进一步用于高性能联合雷达通信系统的封装。
{"title":"A D-Band Self-Packaged Low Loss Grounded Coplanar Waveguide to Rectangular Waveguide Transition With Silicon-Based Air Cavity-Backed Structure","authors":"Zi-Qi Zhang;Xiao-Long Huang;Liang Zhou;Yin-Shan Huang;Cheng-Rui Zhang","doi":"10.1109/JMW.2024.3459909","DOIUrl":"https://doi.org/10.1109/JMW.2024.3459909","url":null,"abstract":"A novel D-band self-packaged silicon-based air cavity-backed transition from grounded coplanar waveguide to air-filled rectangular waveguide was investigated, fabricated, and measured in this work. The equivalent circuit model was established and analyzed in detail, and design procedures are given. The calculated, simulated, and measured S-parameters of the transition show some agreement. The minimum measured insertion loss of the proposed transition is 1.1 dB at 147 GHz with a fractional 3-dB bandwidth of 10.2%. This transition demonstrates outstanding performance of low loss and profile compared with state-of-the art works in our in-house silicon-based MEMS photosensitive composite film fabrication process. It can be further used in a high-performance joint radar communication system in packaging.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 4","pages":"767-776"},"PeriodicalIF":6.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10699397","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142408877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1109/JMW.2024.3453325
Tianze Li;Lei Li;Xiaopeng Wang;James C. M. Hwang;Shana Yanagimoto;Yoshiyuki Yanagimoto
Hexagonal semiconductors such as 4H SiC have important high-frequency, high-power, and high-temperature applications. The applications require accurate knowledge of both ordinary and extraordinary relative permittivities, ϵ ⊥ and ϵ || , perpendicular and parallel, respectively, to the c axis of these semiconductors. However, due to challenges for suitable test setups and precision high-frequency measurements, little reliable data exists for these semiconductors especially at millimeter-wave frequencies. Recently, we reported ϵ || of 4H SiC from 110 to 170 GHz. This paper expands on the previous report to include both ϵ ⊥ and ϵ || of the same material from 55 to 330 GHz, as well as their temperature and humidity dependence enabled by improving the measurement precision to two decimal points. For example, at room temperature, real ϵ ⊥ and ϵ || are constant at 9.77 ± 0.01 and 10.20 ± 0.05, respectively. By contrast, the ordinary loss tangent increases linearly with the frequency f in the form of (4.9 ± 0.1) × 10 −16f . The loss tangent, less than 1 × 10 −4 over most millimeter-wave frequencies, is significantly lower than that of sapphire, our previous low-loss standard. Finally, both ϵ ⊥ and ϵ || have weak temperature coefficients on the order of 10 −4 /°C. The knowledge reported here is especially critical to millimeter-wave applications of 4H SiC, not only for solid-state devices and circuits, but also as windows for high-power vacuum electronics.
{"title":"Ordinary and Extraordinary Permittivities of 4H SiC at Different Millimeter-Wave Frequencies, Temperatures, and Humidities","authors":"Tianze Li;Lei Li;Xiaopeng Wang;James C. M. Hwang;Shana Yanagimoto;Yoshiyuki Yanagimoto","doi":"10.1109/JMW.2024.3453325","DOIUrl":"https://doi.org/10.1109/JMW.2024.3453325","url":null,"abstract":"Hexagonal semiconductors such as 4H SiC have important high-frequency, high-power, and high-temperature applications. The applications require accurate knowledge of both ordinary and extraordinary relative permittivities, \u0000<italic>ϵ</i>\u0000<sub>⊥</sub>\u0000 and \u0000<italic>ϵ</i>\u0000<sub>||</sub>\u0000, perpendicular and parallel, respectively, to the c axis of these semiconductors. However, due to challenges for suitable test setups and precision high-frequency measurements, little reliable data exists for these semiconductors especially at millimeter-wave frequencies. Recently, we reported \u0000<italic>ϵ</i>\u0000<sub>||</sub>\u0000 of 4H SiC from 110 to 170 GHz. This paper expands on the previous report to include both \u0000<italic>ϵ</i>\u0000<sub>⊥</sub>\u0000 and \u0000<italic>ϵ</i>\u0000<sub>||</sub>\u0000 of the same material from 55 to 330 GHz, as well as their temperature and humidity dependence enabled by improving the measurement precision to two decimal points. For example, at room temperature, real \u0000<italic>ϵ</i>\u0000<sub>⊥</sub>\u0000 and \u0000<italic>ϵ</i>\u0000<sub>||</sub>\u0000 are constant at 9.77 ± 0.01 and 10.20 ± 0.05, respectively. By contrast, the ordinary loss tangent increases linearly with the frequency \u0000<italic>f</i>\u0000 in the form of (4.9 ± 0.1) × 10\u0000<sup>−16</sup>\u0000 \u0000<italic>f</i>\u0000. The loss tangent, less than 1 × 10\u0000<sup>−4</sup>\u0000 over most millimeter-wave frequencies, is significantly lower than that of sapphire, our previous low-loss standard. Finally, both \u0000<italic>ϵ</i>\u0000<sub>⊥</sub>\u0000 and \u0000<italic>ϵ</i>\u0000<sub>||</sub>\u0000 have weak temperature coefficients on the order of 10\u0000<sup>−4</sup>\u0000 /°C. The knowledge reported here is especially critical to millimeter-wave applications of 4H SiC, not only for solid-state devices and circuits, but also as windows for high-power vacuum electronics.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 4","pages":"666-674"},"PeriodicalIF":6.9,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10684839","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142408730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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