Pub Date : 2024-02-07DOI: 10.1109/TTHZ.2024.3363135
Martin Wienold;Alexej D. Semenov;Enrico Dietz;Sven Frohmann;Patrick Dern;Xiang Lü;Lutz Schrottke;Klaus Biermann;Bernd Klein;Heinz-Wilhelm Hübers
The oxygen spectrometer for atmospheric science on a balloon (OSAS-B) is the first 4.7-THz heterodyne spectrometer on a stratospheric balloon. It has been developed for remote sensing of the 4.7-THz emission of neutral atomic oxygen in the mesosphere and lower thermosphere of the Earth. OSAS-B comprises a heterodyne receiver based on a hot-electron bolometer mixer and a quantum-cascade laser as local oscillator. The high sensitivity of the superconducting detector and the large resolving power of approximately $1times 10^{7}$ enable the detection of subtle signatures of radiation transport and high-altitude winds in the measured spectra. The first flight of the instrument took place on September 7th, 2022 from Esrange, Sweden.
{"title":"OSAS-B: A Balloon-Borne Terahertz Spectrometer for Atomic Oxygen in the Upper Atmosphere","authors":"Martin Wienold;Alexej D. Semenov;Enrico Dietz;Sven Frohmann;Patrick Dern;Xiang Lü;Lutz Schrottke;Klaus Biermann;Bernd Klein;Heinz-Wilhelm Hübers","doi":"10.1109/TTHZ.2024.3363135","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3363135","url":null,"abstract":"The oxygen spectrometer for atmospheric science on a balloon (OSAS-B) is the first 4.7-THz heterodyne spectrometer on a stratospheric balloon. It has been developed for remote sensing of the 4.7-THz emission of neutral atomic oxygen in the mesosphere and lower thermosphere of the Earth. OSAS-B comprises a heterodyne receiver based on a hot-electron bolometer mixer and a quantum-cascade laser as local oscillator. The high sensitivity of the superconducting detector and the large resolving power of approximately \u0000<inline-formula><tex-math>$1times 10^{7}$</tex-math></inline-formula>\u0000 enable the detection of subtle signatures of radiation transport and high-altitude winds in the measured spectra. The first flight of the instrument took place on September 7th, 2022 from Esrange, Sweden.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 3","pages":"327-335"},"PeriodicalIF":3.2,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140820348","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 : 2024-01-25DOI: 10.1109/TTHZ.2024.3358738
Suzanna Freer;Jie Qing;Pavel Penchev;Stefan Dimov;Stephen M. Hanham;Miguel Navarro-Cía
For the application of geometrically induced THz surface wave technology for communication and sensing, a critical analysis of the propagation characteristics (i.e., dispersion and attenuation) for different textured surfaces should be studied and benchmarked. For the broadband characterization of archetypal textured surfaces (e.g., corrugated plane, 2-D array of blind holes and bed of nails) supporting THz transverse magnetic (i.e., p-polarized) surface waves, we employ time-domain spectroscopy and edge-diffraction coupling methods. Measurements of laser micromachined prototypes demonstrate strong frequency-dependent dispersion and the large impact that surface roughness of the order of few $mu$ m has on the path loss, increasing it by a factor ranging from 1.6 to 4.3 compared to smooth textured surfaces. Together with numerical modeling, we disentangle all loss mechanisms (namely, ohmic, scattering, propagation divergence, and phase mismatch) and highlight the challenge of loss estimation due to surface roughness in highly confined THz surface waves.
为将几何诱导太赫兹表面波技术应用于通信和传感，应研究和评估不同纹理表面的传播特性（即色散和衰减）。为了对支持太赫兹横磁（即 p 极化）表面波的典型纹理表面（如波纹平面、二维盲孔阵列和钉床）进行宽带表征，我们采用了时域光谱和边缘衍射耦合方法。对激光微机械原型的测量结果表明，频率相关的色散很强，而且表面粗糙度只有几毫米，对路径损耗的影响很大，与光滑的纹理表面相比，路径损耗增加了 1.6 到 4.3 倍。结合数值建模，我们分解了所有损耗机制（即欧姆、散射、传播发散和相位失配），并强调了在高度约束的太赫兹表面波中，由于表面粗糙度而导致的损耗估计所面临的挑战。
{"title":"Loss Characteristics of TeraHertz Surface Waves on Laser Micromachined Textured Metals","authors":"Suzanna Freer;Jie Qing;Pavel Penchev;Stefan Dimov;Stephen M. Hanham;Miguel Navarro-Cía","doi":"10.1109/TTHZ.2024.3358738","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3358738","url":null,"abstract":"For the application of geometrically induced THz surface wave technology for communication and sensing, a critical analysis of the propagation characteristics (i.e., dispersion and attenuation) for different textured surfaces should be studied and benchmarked. For the broadband characterization of archetypal textured surfaces (e.g., corrugated plane, 2-D array of blind holes and bed of nails) supporting THz transverse magnetic (i.e., p-polarized) surface waves, we employ time-domain spectroscopy and edge-diffraction coupling methods. Measurements of laser micromachined prototypes demonstrate strong frequency-dependent dispersion and the large impact that surface roughness of the order of few \u0000<inline-formula><tex-math>$mu$</tex-math></inline-formula>\u0000m has on the path loss, increasing it by a factor ranging from 1.6 to 4.3 compared to smooth textured surfaces. Together with numerical modeling, we disentangle all loss mechanisms (namely, ohmic, scattering, propagation divergence, and phase mismatch) and highlight the challenge of loss estimation due to surface roughness in highly confined THz surface waves.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 2","pages":"283-292"},"PeriodicalIF":3.2,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140031689","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 : 2024-01-25DOI: 10.1109/TTHZ.2024.3358735
Mingxiang Stephen Li;Mariam Abdullah;Jiayuan He;Ke Wang;Christophe Fumeaux;Withawat Withayachumnankul
The IEEE 802.15.3d standard for point-to-point wireless terahertz communications is defined to support high-capacity channels. By nature, terahertz signal transmission requires line-of-sight propagation and terahertz communications operates within a challenging power budget limitation. Therefore, accurate and efficient direction-of-arrival (DoA) estimation for maximizing received power becomes paramount to achieve reliable terahertz communications. In this article, we present a frequency-diverse antenna with a machine-learning-based approach utilizing convolutional neural networks (CNNs) to estimate DoA in the terahertz communications band. The antenna is deliberately designed to break symmetry, generating quasi-random radiation patterns, while the CNN captures the relationship between the radiation patterns and their respective angles of arrival. Based on experiments, the DoA estimation results converge to a minimum validation mean squared error of 3.9 $^circ$ and root mean squared error of 1.9 $^circ$ . The estimation efficacy is further substantiated by a consistent performance demonstrated across diverse scenarios, encompassing various obstacles and absorbers around the propagation path. The proposed DoA estimation method shows considerable advantages as a compact, integrable, and cost-effective solution for practical terahertz communications.
{"title":"Frequency-Diverse Antenna With Convolutional Neural Networks for Direction-of-Arrival Estimation in Terahertz Communications","authors":"Mingxiang Stephen Li;Mariam Abdullah;Jiayuan He;Ke Wang;Christophe Fumeaux;Withawat Withayachumnankul","doi":"10.1109/TTHZ.2024.3358735","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3358735","url":null,"abstract":"The IEEE 802.15.3d standard for point-to-point wireless terahertz communications is defined to support high-capacity channels. By nature, terahertz signal transmission requires line-of-sight propagation and terahertz communications operates within a challenging power budget limitation. Therefore, accurate and efficient direction-of-arrival (DoA) estimation for maximizing received power becomes paramount to achieve reliable terahertz communications. In this article, we present a frequency-diverse antenna with a machine-learning-based approach utilizing convolutional neural networks (CNNs) to estimate DoA in the terahertz communications band. The antenna is deliberately designed to break symmetry, generating quasi-random radiation patterns, while the CNN captures the relationship between the radiation patterns and their respective angles of arrival. Based on experiments, the DoA estimation results converge to a minimum validation mean squared error of 3.9\u0000<inline-formula><tex-math>$^circ$</tex-math></inline-formula>\u0000 and root mean squared error of 1.9\u0000<inline-formula><tex-math>$^circ$</tex-math></inline-formula>\u0000. The estimation efficacy is further substantiated by a consistent performance demonstrated across diverse scenarios, encompassing various obstacles and absorbers around the propagation path. The proposed DoA estimation method shows considerable advantages as a compact, integrable, and cost-effective solution for practical terahertz communications.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 3","pages":"354-363"},"PeriodicalIF":3.2,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140820271","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 : 2024-01-25DOI: 10.1109/TTHZ.2024.3358616
Tim Vogel;Samira Mansourzadeh;Uttam Nandi;Justin Norman;Sascha Preu;Clara J. Saraceno
In the last few years, many advances have been made in the demonstration of high-average power pulsed THz sources; however, little effort has been made to study compatible sensitive field-resolved detectors. Here, we investigate ErAs:InAlGaAs photoconductive receivers optimized for a probe wavelength of 1030 nm and thus suitable for the new class of high-power ultrafast Ytterbium-based laser sources for THz generation and detection. The performance of the receiver is tested with a few-cycle THz source with high average power up to 20 mW and the dynamic range and saturation behavior of the receiver is thoroughly characterized. Under optimized settings, a dynamic range of more than 115 dB is reached in a 120 s measurement time with 20 mW of THz average power, which is among the highest reported values to date. By reviewing the state-of-the art in time domain spectroscopy measurement and postprocessing technology, we identify current limitations and guidelines for further increasing the dynamic range toward 150 dB in short measurement times using high average power THz systems with sensitive photoconductive receivers.
{"title":"Performance of Photoconductive Receivers at 1030 nm Excited by High Average Power THz Pulses","authors":"Tim Vogel;Samira Mansourzadeh;Uttam Nandi;Justin Norman;Sascha Preu;Clara J. Saraceno","doi":"10.1109/TTHZ.2024.3358616","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3358616","url":null,"abstract":"In the last few years, many advances have been made in the demonstration of high-average power pulsed THz sources; however, little effort has been made to study compatible sensitive field-resolved detectors. Here, we investigate ErAs:InAlGaAs photoconductive receivers optimized for a probe wavelength of 1030 nm and thus suitable for the new class of high-power ultrafast Ytterbium-based laser sources for THz generation and detection. The performance of the receiver is tested with a few-cycle THz source with high average power up to 20 mW and the dynamic range and saturation behavior of the receiver is thoroughly characterized. Under optimized settings, a dynamic range of more than 115 dB is reached in a 120 s measurement time with 20 mW of THz average power, which is among the highest reported values to date. By reviewing the state-of-the art in time domain spectroscopy measurement and postprocessing technology, we identify current limitations and guidelines for further increasing the dynamic range toward 150 dB in short measurement times using high average power THz systems with sensitive photoconductive receivers.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 2","pages":"139-151"},"PeriodicalIF":3.2,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10414147","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140031628","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 : 2024-01-25DOI: 10.1109/TTHZ.2024.3358734
Yaqi Jing;Jiale Zhang;Mei Wan;Jiadan Xue;Jianjun Liu;Jianyuan Qin;Zhi Hong;Yong Du
In this article, two kinds of pharmaceutical crystallized polymorphs of ethenzamide (ETZ) and saccharin (SAC) cocrystal were synthesized by both solution crystallization and solid-state grinding methods. Crystal structure analysis revealed that the primary hydrogen-bonding heterosynthon of amide–imide in the form I and form II of ETZ-SAC cocrystal was the same, but the secondary interactions in the extended hydrogen-bonding network were different. In addition, ETZ, SAC, their physical mixture, the form I and form II of ETZ-SAC cocrystal were characterized using terahertz (THz) and Raman spectroscopy. The experimental spectra of THz and Raman showed that ETZ, SAC, and two kinds of polymorphs of ETZ-SAC cocrystal exhibited different characteristic peaks, and THz spectroscopy could distinguish the form I and form II of ETZ-SAC cocrystal, but could not be identified by Raman spectroscopy. Solvent phase transition analysis showed that the result polymorphism of ETZ-SAC cocrystal was not dependent on the polarity of the solvent in the solvent drop grinding experiments, neat grinding and most of solvent drop grinding experiments formed the metastable form II of ETZ-SAC cocrystal. These results indicate that with the in-depth study of pharmaceutical polymorphs of cocrystal, it can be reasonably predicted that polymorphs of cocrystal will have great significance in the development of pharmaceutical cocrystals in the future.
本文采用溶液结晶法和固态研磨法合成了两种药物结晶多晶型的乙内酰胺（ETZ）和糖精（SAC）共晶体。晶体结构分析表明，ETZ-SAC共晶体的Ⅰ型和Ⅱ型中酰胺-酰亚胺的一级氢键异质体相同，但扩展氢键网络中的二级相互作用不同。此外，还利用太赫兹（THz）和拉曼光谱对 ETZ、SAC 及其物理混合物、ETZ-SAC 共晶体的 I 型和 II 型进行了表征。太赫兹和拉曼光谱实验结果表明，ETZ、SAC以及ETZ-SAC共晶体的两种多晶型表现出不同的特征峰，太赫兹光谱可以区分ETZ-SAC共晶体的I型和II型，但拉曼光谱无法识别。溶剂相变分析表明，在溶剂滴磨实验中，ETZ-SAC共晶体的结果多态性与溶剂的极性无关，纯磨和大部分溶剂滴磨实验都形成了ETZ-SAC共晶体的稳定形态II。这些结果表明，随着对药用多晶型共晶体的深入研究，可以合理预测多晶型共晶体在未来药用共晶体的发展中将具有重要意义。
{"title":"Distinguishing Polymorphs of Ethenzamide-Saccharin Cocrystal Based on Terahertz and Raman Vibrational Spectroscopic Techniques","authors":"Yaqi Jing;Jiale Zhang;Mei Wan;Jiadan Xue;Jianjun Liu;Jianyuan Qin;Zhi Hong;Yong Du","doi":"10.1109/TTHZ.2024.3358734","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3358734","url":null,"abstract":"In this article, two kinds of pharmaceutical crystallized polymorphs of ethenzamide (ETZ) and saccharin (SAC) cocrystal were synthesized by both solution crystallization and solid-state grinding methods. Crystal structure analysis revealed that the primary hydrogen-bonding heterosynthon of amide–imide in the form I and form II of ETZ-SAC cocrystal was the same, but the secondary interactions in the extended hydrogen-bonding network were different. In addition, ETZ, SAC, their physical mixture, the form I and form II of ETZ-SAC cocrystal were characterized using terahertz (THz) and Raman spectroscopy. The experimental spectra of THz and Raman showed that ETZ, SAC, and two kinds of polymorphs of ETZ-SAC cocrystal exhibited different characteristic peaks, and THz spectroscopy could distinguish the form I and form II of ETZ-SAC cocrystal, but could not be identified by Raman spectroscopy. Solvent phase transition analysis showed that the result polymorphism of ETZ-SAC cocrystal was not dependent on the polarity of the solvent in the solvent drop grinding experiments, neat grinding and most of solvent drop grinding experiments formed the metastable form II of ETZ-SAC cocrystal. These results indicate that with the in-depth study of pharmaceutical polymorphs of cocrystal, it can be reasonably predicted that polymorphs of cocrystal will have great significance in the development of pharmaceutical cocrystals in the future.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 2","pages":"152-161"},"PeriodicalIF":3.2,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140031630","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 presents a highly integrated novel silicon micromachined single-pole-single-throw waveguide switch based on two microelectromechanically reconfigurable switching surfaces (MEMS-RSs), which allows optimizing the switching performance by tuning the interference between the two such MEMS-RSs utilizing integrated electrostatic comb-drive actuators. The switch prototype is implemented with axially aligned standard WR-3.4 waveguide ports with a total footprint of 3 mm×3.5 mm×1.2 mm. The measured blocking ( off ) state insertion loss (isolation) and return loss, measured between two standard WR-3.4 waveguide flanges, are 28.5–32.5 dB and better than 0.7 dB, and the propagating ( on ) state insertion and return losses are 0.7–1.2 dB and better than 17 dB in the 220–290 GHz frequency band, respectively. The measured results were in excellent agreement with the simulation data, implying 27.5% fractional bandwidth, which is very close to a full waveguide band performance. For further investigations, two variants of the switching circuit with only a single MEMS-RS and without any MEMS-RSs have also been fabricated. The single MEMS-RS switch achieved the off -state isolation, on -state insertion loss, and return loss of only 11.5–12.5 dB, 0.8–1.3 dB, and better than 12 dB from 220 to 274 GHz, respectively, which clearly indicates the drastic performance improvement of the interference-based double MEMS-RS switch design. Moreover, measurement of the waveguide-only reference structure showed that the waveguide section alone attributed to 0.2–0.5 dB of the measured on -state insertion loss of the double MEMS-RS switch, and the rest is due to the introduction of the MEMS-RSs inside the waveguides.
{"title":"A High-Performance 220–290 GHz Micromachined Waveguide Switch Based on Interference Between MEMS Reconfigurable Surfaces","authors":"Armin Karimi;Umer Shah;Suxian Yu;Joachim Oberhammer","doi":"10.1109/TTHZ.2024.3356184","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3356184","url":null,"abstract":"This article presents a highly integrated novel silicon micromachined single-pole-single-throw waveguide switch based on two microelectromechanically reconfigurable switching surfaces (MEMS-RSs), which allows optimizing the switching performance by tuning the interference between the two such MEMS-RSs utilizing integrated electrostatic comb-drive actuators. The switch prototype is implemented with axially aligned standard WR-3.4 waveguide ports with a total footprint of 3 mm×3.5 mm×1.2 mm. The measured blocking (\u0000<sc>off</small>\u0000) state insertion loss (isolation) and return loss, measured between two standard WR-3.4 waveguide flanges, are 28.5–32.5 dB and better than 0.7 dB, and the propagating (\u0000<sc>on</small>\u0000) state insertion and return losses are 0.7–1.2 dB and better than 17 dB in the 220–290 GHz frequency band, respectively. The measured results were in excellent agreement with the simulation data, implying 27.5% fractional bandwidth, which is very close to a full waveguide band performance. For further investigations, two variants of the switching circuit with only a single MEMS-RS and without any MEMS-RSs have also been fabricated. The single MEMS-RS switch achieved the \u0000<sc>off</small>\u0000-state isolation, \u0000<sc>on</small>\u0000-state insertion loss, and return loss of only 11.5–12.5 dB, 0.8–1.3 dB, and better than 12 dB from 220 to 274 GHz, respectively, which clearly indicates the drastic performance improvement of the interference-based double MEMS-RS switch design. Moreover, measurement of the waveguide-only reference structure showed that the waveguide section alone attributed to 0.2–0.5 dB of the measured \u0000<sc>on</small>\u0000-state insertion loss of the double MEMS-RS switch, and the rest is due to the introduction of the MEMS-RSs inside the waveguides.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 2","pages":"188-198"},"PeriodicalIF":3.2,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10409559","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140031629","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 : 2024-01-12DOI: 10.1109/TTHZ.2024.3353155
Subash Khanal;Sofia Rahiminejad;Choonsup Lee;Jacob Willem Kooi;Robert Lin;Goutam Chattopadhyay
This article presents a novel waveguide-based terahertz (THz) variable attenuator, integrated with a piezoelectric motor, to achieve precise and fine step values of signal attenuation. A low-resistivity silicon slab, coated with a thin layer of titanium metal, is inserted inside a waveguide that absorbs some of the electromagnetic waves traveling through the guide. Impedance matching is achieved by gradually perforating the silicon slab and thus, creating variable impedance needed for matching. The amount of signal absorbed by the slab is determined by the sheet resistance value of the metal coating and the position of the slab in the waveguide. A miniature nanometer-scale precision piezoelectric motor is used for precise control of the signal attenuation. In this article, we present the attenuator design for a frequency band of 500–750 GHz where up to 40 dB of signal attenuation was achieved, using a 1.75 mm long silicon slab with a 25 nm titanium metal coating. The presented variable attenuator design offers compactness, scalability, and easy integration with THz sources and receivers. Furthermore, the compact size and low power consumption open up possibilities for implementation on CubeSat/Smallsat/Drone-based platforms, further expanding its potential space applications.
{"title":"A Waveguide-Based Variable Attenuator for Terahertz Applications","authors":"Subash Khanal;Sofia Rahiminejad;Choonsup Lee;Jacob Willem Kooi;Robert Lin;Goutam Chattopadhyay","doi":"10.1109/TTHZ.2024.3353155","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3353155","url":null,"abstract":"This article presents a novel waveguide-based terahertz (THz) variable attenuator, integrated with a piezoelectric motor, to achieve precise and fine step values of signal attenuation. A low-resistivity silicon slab, coated with a thin layer of titanium metal, is inserted inside a waveguide that absorbs some of the electromagnetic waves traveling through the guide. Impedance matching is achieved by gradually perforating the silicon slab and thus, creating variable impedance needed for matching. The amount of signal absorbed by the slab is determined by the sheet resistance value of the metal coating and the position of the slab in the waveguide. A miniature nanometer-scale precision piezoelectric motor is used for precise control of the signal attenuation. In this article, we present the attenuator design for a frequency band of 500–750 GHz where up to 40 dB of signal attenuation was achieved, using a 1.75 mm long silicon slab with a 25 nm titanium metal coating. The presented variable attenuator design offers compactness, scalability, and easy integration with THz sources and receivers. Furthermore, the compact size and low power consumption open up possibilities for implementation on CubeSat/Smallsat/Drone-based platforms, further expanding its potential space applications.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 2","pages":"178-187"},"PeriodicalIF":3.2,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140031688","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 : 2024-01-05DOI: 10.1109/TTHZ.2024.3350515
Pranith Reddy Byreddy;Yukun Zhu;Suprovo Ghosh;Harshpreet Singh Bakshi;Walter Sosa Portillo;Jayson P. Van Marter;Kenneth K. O;Murat Torlak;Wooyeol Choi
A 1 × 3 array of 296-GHz complementary metal oxide semiconductor concurrent transceiver pixels incorporating a low noise amplifier, a differential gain stage, and a double-balanced I/Q mixer and a quadrature local oscillator generator for extraction of baseband signal amplitude and phase in addition to the RF section in an area of ∼ (λ/2) 2 is demonstrated. The effective isotropic radiated power of the array is ∼−6 dBm and the minimum double sideband receiver pixel noise figure is ∼48 dB. An E-shaped patch antenna is used to broaden the antenna bandwidth (14-GHz -10-dB |S 11 | bandwidth). Using a pair of these arrays, lens-less short-range reflection mode imaging of a target ∼1 cm away through a cardboard covering is demonstrated. The phase and amplitude outputs enable a synthetic increase of the effective aperture to the scan area from the pixel area for improved image quality and resolution. The use of phase combining for the 1 × 3 transmitter array also improves the isolation between the pair for reflection-mode imaging which limits the stand-off range by ∼10 dB (to ∼70 dB) compared to that when a pair of single pixels with a conductive wall is used.
{"title":"Array of 296-GHz CMOS Concurrent Transceiver Pixels With Phase and Amplitude Extraction Circuits for Improving Reflection-Mode Imaging Resolution","authors":"Pranith Reddy Byreddy;Yukun Zhu;Suprovo Ghosh;Harshpreet Singh Bakshi;Walter Sosa Portillo;Jayson P. Van Marter;Kenneth K. O;Murat Torlak;Wooyeol Choi","doi":"10.1109/TTHZ.2024.3350515","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3350515","url":null,"abstract":"A 1 × 3 array of 296-GHz complementary metal oxide semiconductor concurrent transceiver pixels incorporating a low noise amplifier, a differential gain stage, and a double-balanced I/Q mixer and a quadrature local oscillator generator for extraction of baseband signal amplitude and phase in addition to the RF section in an area of ∼ (λ/2)\u0000<sup>2</sup>\u0000 is demonstrated. The effective isotropic radiated power of the array is ∼−6 dBm and the minimum double sideband receiver pixel noise figure is ∼48 dB. An E-shaped patch antenna is used to broaden the antenna bandwidth (14-GHz -10-dB |S\u0000<sub>11</sub>\u0000| bandwidth). Using a pair of these arrays, lens-less short-range reflection mode imaging of a target ∼1 cm away through a cardboard covering is demonstrated. The phase and amplitude outputs enable a synthetic increase of the effective aperture to the scan area from the pixel area for improved image quality and resolution. The use of phase combining for the 1 × 3 transmitter array also improves the isolation between the pair for reflection-mode imaging which limits the stand-off range by ∼10 dB (to ∼70 dB) compared to that when a pair of single pixels with a conductive wall is used.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 2","pages":"216-227"},"PeriodicalIF":3.2,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140031720","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 : 2024-01-04DOI: 10.1109/TTHZ.2023.3345671
{"title":"IEEE Microwave Theory and Techniques Society Information","authors":"","doi":"10.1109/TTHZ.2023.3345671","DOIUrl":"https://doi.org/10.1109/TTHZ.2023.3345671","url":null,"abstract":"","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 1","pages":"C2-C2"},"PeriodicalIF":3.2,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10381492","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139109440","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 : 2024-01-04DOI: 10.1109/TTHZ.2023.3345673
{"title":"IEEE Transactions on Terahertz Science and Technology Information for Authors","authors":"","doi":"10.1109/TTHZ.2023.3345673","DOIUrl":"https://doi.org/10.1109/TTHZ.2023.3345673","url":null,"abstract":"","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 1","pages":"134-135"},"PeriodicalIF":3.2,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10381507","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139109448","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：