Pub Date : 2025-04-14DOI: 10.1109/TTHZ.2025.3559074
Pierre Koleják;Jiaming Liu;Robin Silber;Martin Mičica;Ondřej Ballada;Čestmír Barta;Romain Lebrun;Nicolas Tiercelin;Mathias Vanwolleghem;Kamil Postava
In this article, we introduce terahertz complete time-domain spectroscopic ellipsometry (THz-cTDSE), extending traditional ellipsometry by determining full Jones and Mueller matrices for in-depth material characterization. This marks the first application of spintronic terahertz emitters in ellipsometry, achieving pure linear polarization for precise magnetization-based switching. Our complete phase-resolved ellipsometry transforms Jones matrices into an intuitive framework of diattenuations and retardations across all Stokes bases—Pauli exponential coefficients—previously unattainable with incomplete ellipsometry. A novel calibration technique ensures accurate Jones matrix reconstruction without requiring precise alignment of polarizing components, approaching the precision typical of visible-range ellipsometry. We demonstrate THz-cTDSE on quartz and Hg$_{2}$Cl$_{2}$ crystals, advancing the analysis of anisotropic materials.
{"title":"Terahertz Time-Domain Ellipsometry With Spintronic Emitters: Pauli Coefficients as a Superior Alternative to Jones and Mueller Matrices","authors":"Pierre Koleják;Jiaming Liu;Robin Silber;Martin Mičica;Ondřej Ballada;Čestmír Barta;Romain Lebrun;Nicolas Tiercelin;Mathias Vanwolleghem;Kamil Postava","doi":"10.1109/TTHZ.2025.3559074","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3559074","url":null,"abstract":"In this article, we introduce terahertz complete time-domain spectroscopic ellipsometry (THz-cTDSE), extending traditional ellipsometry by determining full Jones and Mueller matrices for in-depth material characterization. This marks the first application of spintronic terahertz emitters in ellipsometry, achieving pure linear polarization for precise magnetization-based switching. Our complete phase-resolved ellipsometry transforms Jones matrices into an intuitive framework of diattenuations and retardations across all Stokes bases—Pauli exponential coefficients—previously unattainable with incomplete ellipsometry. A novel calibration technique ensures accurate Jones matrix reconstruction without requiring precise alignment of polarizing components, approaching the precision typical of visible-range ellipsometry. We demonstrate THz-cTDSE on quartz and Hg<inline-formula><tex-math>$_{2}$</tex-math></inline-formula>Cl<inline-formula><tex-math>$_{2}$</tex-math></inline-formula> crystals, advancing the analysis of anisotropic materials.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 4","pages":"606-621"},"PeriodicalIF":3.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10964355","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144550488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-10DOI: 10.1109/TTHZ.2025.3557318
Meicun Kang;Lijun Yang;Yuxin He;Li Cheng;Hao Luo
Moisture content is a decisive factor for the electrical performance of oil–paper insulation. As a strongly polar substance, moisture can easily accumulate in areas with high field strength, distorting the local electric field and triggering electrical discharges. However, due to the lack of suitable nondestructive observation means, no experimental and observational studies have been conducted on the effect of the electric field on the migration and aggregation behavior of moisture in insulating pressboard. In this work, a terahertz imaging technique is introduced to observe the diffusive migration of moisture in insulating pressboard and focus on the effect of the ac electric field on this process. Results show that moisture migration in insulating pressboard consists of two parts: migration from solid-phase insulating pressboard to liquid-phase insulating oil and migration occurring in solid-phase insulating pressboard. The addition of the ac electric field considerably increases the diffusion rate of moisture and accelerates the migration of moisture from the solid phase to the liquid phase. Moreover, the electric field makes the moisture in the solid-phase pressboard migrate and accumulate toward the high-field-strength region near electrodes, and this process is accelerated by the increase in temperature. Under the experimental conditions of this study, the maximum relative deviation between the moisture content in the pressboard near both sides of the electrode and the average moisture content is 34.7%.
{"title":"Migration and Accumulation Behavior of Moisture in Insulating Pressboard Under AC Field by Terahertz Imaging Technology","authors":"Meicun Kang;Lijun Yang;Yuxin He;Li Cheng;Hao Luo","doi":"10.1109/TTHZ.2025.3557318","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3557318","url":null,"abstract":"Moisture content is a decisive factor for the electrical performance of oil–paper insulation. As a strongly polar substance, moisture can easily accumulate in areas with high field strength, distorting the local electric field and triggering electrical discharges. However, due to the lack of suitable nondestructive observation means, no experimental and observational studies have been conducted on the effect of the electric field on the migration and aggregation behavior of moisture in insulating pressboard. In this work, a terahertz imaging technique is introduced to observe the diffusive migration of moisture in insulating pressboard and focus on the effect of the ac electric field on this process. Results show that moisture migration in insulating pressboard consists of two parts: migration from solid-phase insulating pressboard to liquid-phase insulating oil and migration occurring in solid-phase insulating pressboard. The addition of the ac electric field considerably increases the diffusion rate of moisture and accelerates the migration of moisture from the solid phase to the liquid phase. Moreover, the electric field makes the moisture in the solid-phase pressboard migrate and accumulate toward the high-field-strength region near electrodes, and this process is accelerated by the increase in temperature. Under the experimental conditions of this study, the maximum relative deviation between the moisture content in the pressboard near both sides of the electrode and the average moisture content is 34.7%.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 4","pages":"622-633"},"PeriodicalIF":3.9,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144550482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-09DOI: 10.1109/TTHZ.2025.3558962
Sara Vega;Daniel Nuño;Yi Chang;Juan Sebastian Gómez-Díaz;María Santos
We present a study of the radiation pattern of photoconductive antennas (PCA) subject to substrate chip defects, aiming at characterizing fabrication tolerances. We show that the asymmetries observed over the crosspolar radiation patterns may be exploited to numerically estimate the most prominent trends of the substrate chip geometrical imperfections. A figure of merit (FoM) has been defined, characterized, and validated through simulations and experimental measures, proving it is sensitive to both the magnitude and location of the substrate irregularities. The study has been focused on two kinds of substrate defects, the angled dicing and the off-centered antenna gap, and it has considered three planar antenna geometries: dipole, bow-tie and Sierpinski triangle dipole. A numerical antenna factor related to the planar antenna geometry imprinted over the substrate is included in the FoM expression for fair comparison of substrate irregularities among PCAs with different metallic patterns. A simple setup for experimentally obtaining the value of the FoM through collimated beam raster scanning measure of the crosspolar radiation pattern has been proved useful to validate the practical relevance of the FoM. These values asses the substrate chip fabrication quality and help to identify the position and magnitude of the substrate defects that have the greatest impact on the PCA performance.
{"title":"On the Influence of Fabrication Tolerances in Terahertz Photoconductive Antennas","authors":"Sara Vega;Daniel Nuño;Yi Chang;Juan Sebastian Gómez-Díaz;María Santos","doi":"10.1109/TTHZ.2025.3558962","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3558962","url":null,"abstract":"We present a study of the radiation pattern of photoconductive antennas (PCA) subject to substrate chip defects, aiming at characterizing fabrication tolerances. We show that the asymmetries observed over the crosspolar radiation patterns may be exploited to numerically estimate the most prominent trends of the substrate chip geometrical imperfections. A figure of merit (FoM) has been defined, characterized, and validated through simulations and experimental measures, proving it is sensitive to both the magnitude and location of the substrate irregularities. The study has been focused on two kinds of substrate defects, the angled dicing and the off-centered antenna gap, and it has considered three planar antenna geometries: dipole, bow-tie and Sierpinski triangle dipole. A numerical antenna factor related to the planar antenna geometry imprinted over the substrate is included in the FoM expression for fair comparison of substrate irregularities among PCAs with different metallic patterns. A simple setup for experimentally obtaining the value of the FoM through collimated beam raster scanning measure of the crosspolar radiation pattern has been proved useful to validate the practical relevance of the FoM. These values asses the substrate chip fabrication quality and help to identify the position and magnitude of the substrate defects that have the greatest impact on the PCA performance.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 4","pages":"634-641"},"PeriodicalIF":3.9,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144550718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-02DOI: 10.1109/TTHZ.2025.3557312
Sebastian Mueller;Thomas Puppe;Timo Noack;Martin Wittmann;Gerd Hechtfischer;Nico Vieweg
We have developed, manufactured, and characterized a WM-570 rectangular waveguide bandpass filter with a central frequency of 415 GHz. Initially, a vector network analyzer (VNA) with millimeter-wave converters was employed to determine the transfer function of the filter within the WM-570 band of 330–500 GHz. Subsequently, we utilized a frequency-comb locked continuous-wave terahertz spectrometer to cover a frequency range from 300 to 800 GHz, spanning several waveguide bands. Using this system, in addition to the designed passband around 415 GHz, we identified several other features at higher frequencies, particularly beyond the measurement range of the VNA converter setup employed. The measurements agree well with the simulation, even at frequencies beyond the operational bandwidth of the WM-570 waveguide. This demonstrates the potential of a tunable optical source to characterize measurement instrumentation up to THz frequencies.
{"title":"Photonic, Broadband, and High-Resolution Characterization of a 415 GHz Waveguide Bandpass Filter","authors":"Sebastian Mueller;Thomas Puppe;Timo Noack;Martin Wittmann;Gerd Hechtfischer;Nico Vieweg","doi":"10.1109/TTHZ.2025.3557312","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3557312","url":null,"abstract":"We have developed, manufactured, and characterized a WM-570 rectangular waveguide bandpass filter with a central frequency of 415 GHz. Initially, a vector network analyzer (VNA) with millimeter-wave converters was employed to determine the transfer function of the filter within the WM-570 band of 330–500 GHz. Subsequently, we utilized a frequency-comb locked continuous-wave terahertz spectrometer to cover a frequency range from 300 to 800 GHz, spanning several waveguide bands. Using this system, in addition to the designed passband around 415 GHz, we identified several other features at higher frequencies, particularly beyond the measurement range of the VNA converter setup employed. The measurements agree well with the simulation, even at frequencies beyond the operational bandwidth of the WM-570 waveguide. This demonstrates the potential of a tunable optical source to characterize measurement instrumentation up to THz frequencies.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 4","pages":"728-733"},"PeriodicalIF":3.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144550614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1109/TTHZ.2025.3555599
Tobias Doeker;Lorenz H. W. Loeser;Thomas Kürner
For wireless communication systems, beam tracking is crucial if the transmitter and/or the receiver is nonstatic. Specifically, for a communication system in the low terahertz frequency range, beam tracking becomes mandatory due to the necessity for highly directive antennas with narrow beams. Therefore, a beam tracking algorithm for horn antennas specified for 300 GHz has been developed. The proposed algorithm uses changes in antenna gain due to the movement of the transmitter and/or receiver. The received power and information about the antenna radiation pattern allow for the prediction of the angle of departure and angle of arrival. Basic verification of the algorithm has already been conducted through simulation and should now be verified under real conditions through measurements. This article presents a measurement campaign conducted with a channel sounding system around 300 GHz. According to the description of the algorithm provided at the beginning of this article, the measurement results are evaluated for both line-of-sight and non-line-of-sight scenarios. The measurement data are used as input for the algorithm to investigate the possibilities of beam tracking in a real system. It is shown that the algorithm can reliably predict angular changes in both line-of-sight and non-line-of-sight cases. With an accuracy of $pm$ 1$^{circ }$, angular changes of up to 20$^{circ }$ can be tracked using information from four different transmitter and receiver antenna combinations. Even higher angular ranges, up to 70$^{circ }$ in the line-of-sight case and 45$^{circ }$ in the non-line-of-sight case, can be tracked if the accuracy value is increased to $pm$ 4$^{circ }$. The proposed algorithm has, thus, been verified both through simulation and real measurements.
{"title":"Measurements and Verification of an Antenna Pattern-Based Tracking Algorithm at 300 GHz","authors":"Tobias Doeker;Lorenz H. W. Loeser;Thomas Kürner","doi":"10.1109/TTHZ.2025.3555599","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3555599","url":null,"abstract":"For wireless communication systems, beam tracking is crucial if the transmitter and/or the receiver is nonstatic. Specifically, for a communication system in the low terahertz frequency range, beam tracking becomes mandatory due to the necessity for highly directive antennas with narrow beams. Therefore, a beam tracking algorithm for horn antennas specified for 300 GHz has been developed. The proposed algorithm uses changes in antenna gain due to the movement of the transmitter and/or receiver. The received power and information about the antenna radiation pattern allow for the prediction of the angle of departure and angle of arrival. Basic verification of the algorithm has already been conducted through simulation and should now be verified under real conditions through measurements. This article presents a measurement campaign conducted with a channel sounding system around 300 GHz. According to the description of the algorithm provided at the beginning of this article, the measurement results are evaluated for both line-of-sight and non-line-of-sight scenarios. The measurement data are used as input for the algorithm to investigate the possibilities of beam tracking in a real system. It is shown that the algorithm can reliably predict angular changes in both line-of-sight and non-line-of-sight cases. With an accuracy of <inline-formula><tex-math>$pm$</tex-math></inline-formula> 1<inline-formula><tex-math>$^{circ }$</tex-math></inline-formula>, angular changes of up to 20<inline-formula><tex-math>$^{circ }$</tex-math></inline-formula> can be tracked using information from four different transmitter and receiver antenna combinations. Even higher angular ranges, up to 70<inline-formula><tex-math>$^{circ }$</tex-math></inline-formula> in the line-of-sight case and 45<inline-formula><tex-math>$^{circ }$</tex-math></inline-formula> in the non-line-of-sight case, can be tracked if the accuracy value is increased to <inline-formula><tex-math>$pm$</tex-math></inline-formula> 4<inline-formula><tex-math>$^{circ }$</tex-math></inline-formula>. The proposed algorithm has, thus, been verified both through simulation and real measurements.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 3","pages":"359-369"},"PeriodicalIF":3.9,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-27DOI: 10.1109/TTHZ.2025.3555418
Fabien Defrance;Cecile Jung-Kubiak;John Gill;Sofia Rahiminejad;Theodore Macioce;Jack Sayers;Goutam Chattopadhyay;Sunil R. Golwala
In this article, we present the design, fabrication, and characterization of a 100 mm diameter, flat, gradient-index (GRIN) lens fabricated with high-resistivity silicon, combined with a three-layer antireflection (AR) structure optimized for 160–355 GHz. Multidepth, deep reactive-ion etching enables patterning of silicon wafers with subwavelength structures (posts or holes) to locally change the effective refractive index and, thus, create AR layers and a radial index gradient. The structures are nonresonant and, for sufficiently long wavelengths, achromatic. Hexagonal holes varying in size with distance from the optical axis create a parabolic index profile decreasing from 3.15 at the center of the lens to 1.87 at the edge. The AR structure consists of square holes and cross-shaped posts. We have fabricated a lens consisting of a stack of five 525 μm thick GRIN wafers and one AR wafer on each face. We have characterized the lens over the frequency range 220–330 GHz, obtaining behavior consistent with Gaussian optics down to −14 dB and transmittance of 99$pm$3%.
{"title":"Flat Silicon Gradient Index Lens With Deep Reactive-Ion-Etched Three-Layer Antireflection Structure for Millimeter and Submillimeter Wavelengths","authors":"Fabien Defrance;Cecile Jung-Kubiak;John Gill;Sofia Rahiminejad;Theodore Macioce;Jack Sayers;Goutam Chattopadhyay;Sunil R. Golwala","doi":"10.1109/TTHZ.2025.3555418","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3555418","url":null,"abstract":"In this article, we present the design, fabrication, and characterization of a 100 mm diameter, flat, gradient-index (GRIN) lens fabricated with high-resistivity silicon, combined with a three-layer antireflection (AR) structure optimized for 160–355 GHz. Multidepth, deep reactive-ion etching enables patterning of silicon wafers with subwavelength structures (posts or holes) to locally change the effective refractive index and, thus, create AR layers and a radial index gradient. The structures are nonresonant and, for sufficiently long wavelengths, achromatic. Hexagonal holes varying in size with distance from the optical axis create a parabolic index profile decreasing from 3.15 at the center of the lens to 1.87 at the edge. The AR structure consists of square holes and cross-shaped posts. We have fabricated a lens consisting of a stack of five 525 μm thick GRIN wafers and one AR wafer on each face. We have characterized the lens over the frequency range 220–330 GHz, obtaining behavior consistent with Gaussian optics down to −14 dB and transmittance of 99<inline-formula><tex-math>$pm$</tex-math></inline-formula>3%.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 4","pages":"679-693"},"PeriodicalIF":3.9,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144550389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-26DOI: 10.1109/TTHZ.2025.3573859
Huanxin Li;Xiang Gao;Ziru Chen;Dan Qiao;Xiangyuan Bu;Jianping An
This article presents a dual-port leaky-wave array antenna integrated beam-steerable Schottky heterodyne receiver that may be attractive for terahertz (THz) sensing applications. The receiver chip features a low-cost wideband quasi-optical design that utilizes one frequency-scanning leaky-wave array and one fixed-beam monopole integrated lens antenna for efficiently coupling the radio-frequency (RF) and local-oscillator (LO) signals, respectively. Operating in the subharmonic mixing mode, a dual-channel beam-steerable Schottky heterodyne receiver circuit was designed for performance maximization via both passive and active modeling. A prototype of the THz beam-steerable receiver module was manufactured and experimentally demonstrated. By flexibly switching between seven fixed LO frequencies among 99.5–114.5 GHz, the receiver can reconfigurably detect the RF signal at one of seven equally-divided sub-bands from 200 to 235 GHz, with an intermediate-frequency bandwidth up to 5 GHz. In particular, the receiver can detect the RF beam from unfixed incident direction over a wide steering coverage range of 80°. The measured average single-sideband conversion gain and noise figure are around −9.1 and 9.4 dB, respectively. The results have validated good receiver performance and its potential for sensing applications.
{"title":"A Dual-Port Leaky-Wave Array Antenna Integrated Beam-Steerable Schottky Heterodyne Receiver for Terahertz-Band Applications","authors":"Huanxin Li;Xiang Gao;Ziru Chen;Dan Qiao;Xiangyuan Bu;Jianping An","doi":"10.1109/TTHZ.2025.3573859","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3573859","url":null,"abstract":"This article presents a dual-port leaky-wave array antenna integrated beam-steerable Schottky heterodyne receiver that may be attractive for terahertz (THz) sensing applications. The receiver chip features a low-cost wideband quasi-optical design that utilizes one frequency-scanning leaky-wave array and one fixed-beam monopole integrated lens antenna for efficiently coupling the radio-frequency (RF) and local-oscillator (LO) signals, respectively. Operating in the subharmonic mixing mode, a dual-channel beam-steerable Schottky heterodyne receiver circuit was designed for performance maximization via both passive and active modeling. A prototype of the THz beam-steerable receiver module was manufactured and experimentally demonstrated. By flexibly switching between seven fixed LO frequencies among 99.5–114.5 GHz, the receiver can reconfigurably detect the RF signal at one of seven equally-divided sub-bands from 200 to 235 GHz, with an intermediate-frequency bandwidth up to 5 GHz. In particular, the receiver can detect the RF beam from unfixed incident direction over a wide steering coverage range of 80°. The measured average single-sideband conversion gain and noise figure are around −9.1 and 9.4 dB, respectively. The results have validated good receiver performance and its potential for sensing applications.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 5","pages":"914-926"},"PeriodicalIF":3.9,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144998337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-26DOI: 10.1109/TTHZ.2025.3573847
James Skinner;Daniel Koller;Hans-Ulrich Nickel;Nick M. Ridler;Stepan Lucyszyn
The IEC 60153-2 and IEEE 1785.1 international standards for rectangular metallic waveguides are currently undergoing revision. Textbook derivations of the associated equations for the metal-pipe rectangular waveguide attenuation constant to be given in the revised standards are presented. These derivations provide important mathematical traceability for these equations, which has previously not been proven in the open literature for these standards. Furthermore, the historical approximations used in the original equations are identified and now corrected here. Results using the newly derived equations are demonstrated, with comparison to experimental results in the WM-380 (500 GHz to 750 GHz) band.
{"title":"Derivation of Rectangular Metallic Waveguide Attenuation Constant for IEC 60153-2 and IEEE 1785.1 International Standards","authors":"James Skinner;Daniel Koller;Hans-Ulrich Nickel;Nick M. Ridler;Stepan Lucyszyn","doi":"10.1109/TTHZ.2025.3573847","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3573847","url":null,"abstract":"The IEC 60153-2 and IEEE 1785.1 international standards for rectangular metallic waveguides are currently undergoing revision. Textbook derivations of the associated equations for the metal-pipe rectangular waveguide attenuation constant to be given in the revised standards are presented. These derivations provide important mathematical traceability for these equations, which has previously not been proven in the open literature for these standards. Furthermore, the historical approximations used in the original equations are identified and now corrected here. Results using the newly derived equations are demonstrated, with comparison to experimental results in the WM-380 (500 GHz to 750 GHz) band.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 4","pages":"734-737"},"PeriodicalIF":3.9,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144550483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article highlights two 8×1 transmitter and receiver front-ends, which are individually composed of two inparallel assembled four-channel submillimeter-wave monolithic integrated circuits (S-MMICs) operating at 400 GHz. These S-MMICs integrate frequency multipliers, mixers, and amplifiers as well as on-chip antennas. They are manufactured on a 35 nm metamorphic high-electron-mobility transistor technology. The included to-the-broadside radiating on-chip antennas allowed for simplified assembly on a printed circuit board upon which two 4×1 transmitter or receiver S-MMICs are placed in parallel. Furthermore, a separate multiplier-by-four is integrated allowing for a low-frequency input drive in the range of 22.50 to 26.25 GHz. The operational frequency range of the front-ends is from 360 to 420 GHz. Both on-wafer and front-end level measurements are shown, including the farfield pattern characterization of the respective metastructure-based on-chip antennas. With all eight channels of the transmitter front-end active, a radiated output power of at least 10 mW is achieved for the frequency range from 390 to 420 GHz setting the state-of-the-art.
{"title":"400 GHz 8×1 Transmitter and Receiver Front-Ends With Metastructured On-Chip Antennas","authors":"Bersant Gashi;Sandrine Wagner;Lucas Tetzel;Michael Kuri;Rainer Weber;Philipp Neininger;Axel Tessmann;Arnulf Leuther;Marius Kretschmann;Steffen Wälde;Rüdiger Quay","doi":"10.1109/TTHZ.2025.3554724","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3554724","url":null,"abstract":"This article highlights two 8×1 transmitter and receiver front-ends, which are individually composed of two inparallel assembled four-channel submillimeter-wave monolithic integrated circuits (S-MMICs) operating at 400 GHz. These S-MMICs integrate frequency multipliers, mixers, and amplifiers as well as on-chip antennas. They are manufactured on a 35 nm metamorphic high-electron-mobility transistor technology. The included to-the-broadside radiating on-chip antennas allowed for simplified assembly on a printed circuit board upon which two 4×1 transmitter or receiver S-MMICs are placed in parallel. Furthermore, a separate multiplier-by-four is integrated allowing for a low-frequency input drive in the range of 22.50 to 26.25 GHz. The operational frequency range of the front-ends is from 360 to 420 GHz. Both on-wafer and front-end level measurements are shown, including the farfield pattern characterization of the respective metastructure-based on-chip antennas. With all eight channels of the transmitter front-end active, a radiated output power of at least 10 mW is achieved for the frequency range from 390 to 420 GHz setting the state-of-the-art.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 4","pages":"660-671"},"PeriodicalIF":3.9,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10938385","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144550490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article presents a 220–260 GHz fully integrated phased-array wireless system featuring direct conversion RF beam-forming. The system is constructed using fully integrated transmitter (Tx) and receiver (Rx) chips with on-chip antenna array. A four-channel Tx and Rx are designed and fabricated in a 130-nm SiGe BiCMOS process with f$_{mathbf{T}}$/f$_{mathbf{max}}$ = 300/500 GHz. A modular design approach enables the chips as building units for 2×N phased arrays and multiple-input multiple-output systems. A comprehensive design approach for the Tx and Rx chips focusing on key design decisions is presented in this work. The transmitter is equipped with a local oscillator (LO) multiplication chain, IQ up $-$ conversion mixer, active RF splitting network, vector modulator phase shifter (VMPS), temperature sensors, and high output power amplifiers (PA). The PA with power $-$ combining boost the effective isotropic radiated power (EIRP) and reduces the need for external lenses. The receiver is equipped with an LO chain, IQ down $-$ conversion mixer, active RF combining network, VMPS, and low noise amplifiers (LNA). In both Tx and Rx the antenna array is composed of four differential double-folded dipole antennas with local backside etching. The Tx and Rx chips consume 4.4 W and 1.84 W of power, respectively, from a 3.5 V supply with each occupying 25 mm$^{text{2}}$ of silicon area. With a measured Tx array EIRP of 24 dBm, a beamforming wireless link is demonstrated supporting up to 50 Gbps of data rates across 85 cm of link distance with no need for focusing lenses and $pm 30^circ$ of scanning capability. With these capabilities, the presented modular chips enable future scaling for 2× N antenna arrays for sensing and communication applications.
{"title":"A Fully Integrated Modular 2×4 220–260 GHz Beam-Forming Transmitter and Receiver With 50 Gbps Wireless Transmission in SiGe:C BiCMOS","authors":"Mohamed Hussein Eissa;Nebojsa Maletic;Matthias Wietstruck;Vladica Sark;Andrea Malignaggi;Wael Abdullah;Corrado Carta;Gerhard Kahmen","doi":"10.1109/TTHZ.2025.3573157","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3573157","url":null,"abstract":"This article presents a 220–260 GHz fully integrated phased-array wireless system featuring direct conversion RF beam-forming. The system is constructed using fully integrated transmitter (Tx) and receiver (Rx) chips with on-chip antenna array. A four-channel Tx and Rx are designed and fabricated in a 130-nm SiGe BiCMOS process with <italic>f</i><inline-formula><tex-math>$_{mathbf{T}}$</tex-math></inline-formula>/<italic>f</i><inline-formula><tex-math>$_{mathbf{max}}$</tex-math></inline-formula> = 300/500 GHz. A modular design approach enables the chips as building units for 2×N phased arrays and multiple-input multiple-output systems. A comprehensive design approach for the Tx and Rx chips focusing on key design decisions is presented in this work. The transmitter is equipped with a local oscillator (LO) multiplication chain, IQ up <inline-formula><tex-math>$-$</tex-math></inline-formula> conversion mixer, active RF splitting network, vector modulator phase shifter (VMPS), temperature sensors, and high output power amplifiers (PA). The PA with power <inline-formula><tex-math>$-$</tex-math></inline-formula> combining boost the effective isotropic radiated power (EIRP) and reduces the need for external lenses. The receiver is equipped with an LO chain, IQ down <inline-formula><tex-math>$-$</tex-math></inline-formula> conversion mixer, active RF combining network, VMPS, and low noise amplifiers (LNA). In both Tx and Rx the antenna array is composed of four differential double-folded dipole antennas with local backside etching. The Tx and Rx chips consume 4.4 W and 1.84 W of power, respectively, from a 3.5 V supply with each occupying 25 mm<inline-formula><tex-math>$^{text{2}}$</tex-math></inline-formula> of silicon area. With a measured Tx array EIRP of 24 dBm, a beamforming wireless link is demonstrated supporting up to 50 Gbps of data rates across 85 cm of link distance with no need for focusing lenses and <inline-formula><tex-math>$pm 30^circ$</tex-math></inline-formula> of scanning capability. With these capabilities, the presented modular chips enable future scaling for 2× N antenna arrays for sensing and communication applications.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 5","pages":"805-820"},"PeriodicalIF":3.9,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144998302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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