Pub Date : 2025-08-22DOI: 10.1109/TTHZ.2025.3601724
Suprovat Ghosh;Kritika Bhattacharya;Ananjan Basu;Samaresh Das
This article introduces a scalable and cost-effective fabrication process for a log periodic antenna (LPA) coupled engineered silicon microwire (MW) channel grating junctionless field effect transistor (FET), optimized for enhanced room temperature terahertz (THz) detection. Using this straight forward approach, we demonstrate THz detectors with 1_MW, 5_MW, and 7_MW channel FET. Among these, the 5_MW channel FET exhibits superior cross-sectional current responsivity, significantly outperforming 1_MW and 7_MW device. By leveraging the grating architecture, the 5_MW channel detector achieves approximately a tenfold improvement in cross-sectional current responsivity and better noise-equivalent power (NEP) at 0.29 THz compared to the 1_MW channel detector. Specifically, the 5_MW detector demonstrates a maximum cross-sectional current responsivity of 25.5 mA/W, a detectivity of 1.1 × 10$^{10}$ Jones, and an NEP of 2.5 × 10$mathbf {^{-12}}$ W-Hz $mathbf {^{-1/2}}$ at 0.29 THz under a 1 V gate bias. In addition, simulations are performed on the 5_MW channel grating architecture to study its polarization-sensitive behavior. Overall, this work holds significant potential for advancing THz technology, with further performance improvements possible by implementing the grating channel architecture with 2-D or III–V materials in conjunction with an LPA, paving the way for practical applications in THz sensing and imaging.
{"title":"Junctionless FET With Engineered Silicon Microwire Grating Channels for Enhanced Room-Temperature Terahertz Detection","authors":"Suprovat Ghosh;Kritika Bhattacharya;Ananjan Basu;Samaresh Das","doi":"10.1109/TTHZ.2025.3601724","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3601724","url":null,"abstract":"This article introduces a scalable and cost-effective fabrication process for a log periodic antenna (LPA) coupled engineered silicon microwire (MW) channel grating junctionless field effect transistor (FET), optimized for enhanced room temperature terahertz (THz) detection. Using this straight forward approach, we demonstrate THz detectors with 1_MW, 5_MW, and 7_MW channel FET. Among these, the 5_MW channel FET exhibits superior cross-sectional current responsivity, significantly outperforming 1_MW and 7_MW device. By leveraging the grating architecture, the 5_MW channel detector achieves approximately a tenfold improvement in cross-sectional current responsivity and better noise-equivalent power (NEP) at 0.29 THz compared to the 1_MW channel detector. Specifically, the 5_MW detector demonstrates a maximum cross-sectional current responsivity of 25.5 mA/W, a detectivity of 1.1 × 10<inline-formula><tex-math>$^{10}$</tex-math></inline-formula> Jones, and an NEP of 2.5 × 10<inline-formula><tex-math>$mathbf {^{-12}}$</tex-math></inline-formula> W-Hz <inline-formula><tex-math>$mathbf {^{-1/2}}$</tex-math></inline-formula> at 0.29 THz under a 1 V gate bias. In addition, simulations are performed on the 5_MW channel grating architecture to study its polarization-sensitive behavior. Overall, this work holds significant potential for advancing THz technology, with further performance improvements possible by implementing the grating channel architecture with 2-D or III–V materials in conjunction with an LPA, paving the way for practical applications in THz sensing and imaging.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"16 2","pages":"193-202"},"PeriodicalIF":3.9,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102954","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 : 2025-08-19DOI: 10.1109/TTHZ.2025.3597203
Yapeng Ge;Jiacheng Liu;Jiayuan Cui;Mingxia Zhang;Wenbo Liu;Peian Li;Houjun Sun;Jianjun Ma
As the terahertz (THz) band emerges as a pivotal technology for next-generation wireless communications, accurate channel modeling in dynamic environments becomes increasingly critical, particularly for scenarios involving reflective interactions with water surfaces. This article presents comprehensive experimental and theoretical investigations into THz channel (120–320 GHz) performance under dynamic water surface reflections. By developing and validating a modified dual-scale scattering model based on the improved integral equation model, this work systematically evaluates channel characteristics, such as signal power loss and bit error rate, across various dynamic aquatic scenarios. Laboratory experiments and real-world natatorium measurements demonstrate the model's efficacy in capturing complex temporal and spatial scattering behaviors, offering vital insights and robust predictive capabilities essential for deploying practical THz communication systems in aquatic and sports environments.
{"title":"Terahertz Channel Performance Under Dynamic Water Surface Reflections","authors":"Yapeng Ge;Jiacheng Liu;Jiayuan Cui;Mingxia Zhang;Wenbo Liu;Peian Li;Houjun Sun;Jianjun Ma","doi":"10.1109/TTHZ.2025.3597203","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3597203","url":null,"abstract":"As the terahertz (THz) band emerges as a pivotal technology for next-generation wireless communications, accurate channel modeling in dynamic environments becomes increasingly critical, particularly for scenarios involving reflective interactions with water surfaces. This article presents comprehensive experimental and theoretical investigations into THz channel (120–320 GHz) performance under dynamic water surface reflections. By developing and validating a modified dual-scale scattering model based on the improved integral equation model, this work systematically evaluates channel characteristics, such as signal power loss and bit error rate, across various dynamic aquatic scenarios. Laboratory experiments and real-world natatorium measurements demonstrate the model's efficacy in capturing complex temporal and spatial scattering behaviors, offering vital insights and robust predictive capabilities essential for deploying practical THz communication systems in aquatic and sports environments.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"16 2","pages":"103-117"},"PeriodicalIF":3.9,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102985","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 addresses a critical challenge in high-speed terahertz (THz) systems: sampling frequency offset (SFO) from both intrinsic device characteristics and critically, artificial introduction during system operation. We present a comprehensive study that uniquely examines operation-induced SFO alongside conventional device SFO through a novel sample-per-symbol framework. Our analysis reveals how artificial SFO, often undetected in standard system calibration, can significantly degrade performance beyond typical device limitations. The developed theoretical model precisely quantifies both SFO sources and their combined impact. Experimental validation in a photonics-aided THz-over-fiber polarization-division-multiplexing system demonstrates our method's effectiveness, successfully mitigating both device and artificially introduced SFO to achieve stable 60-GBaud transmission at 0.32-THz. This implementation establishes a record 576-Gb/s/$lambda$ per-channel capacity while providing crucial insights into preventing artificial SFO in practical deployments. The work offers researchers essential tools for identifying and correcting human-induced sampling errors in next-generation THz systems.
{"title":"Equivalent Sampling Frequency Offset in Transceivers: Minimization and Compensation for Broadband Photonics-Aided THz Wireless Transmission Systems","authors":"Jianyu Long;Chen Wang;Jianjun Yu;Ying Wu;Long Zhang;Bohan Sang;Yifan Chen;Xiongwei Yang;Wen Zhou;Kaihui Wang;Li Zhao;Junjie Ding;Jiao Zhang;Min Zhu","doi":"10.1109/TTHZ.2025.3598698","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3598698","url":null,"abstract":"This article addresses a critical challenge in high-speed terahertz (THz) systems: sampling frequency offset (SFO) from both intrinsic device characteristics and critically, artificial introduction during system operation. We present a comprehensive study that uniquely examines operation-induced SFO alongside conventional device SFO through a novel sample-per-symbol framework. Our analysis reveals how artificial SFO, often undetected in standard system calibration, can significantly degrade performance beyond typical device limitations. The developed theoretical model precisely quantifies both SFO sources and their combined impact. Experimental validation in a photonics-aided THz-over-fiber polarization-division-multiplexing system demonstrates our method's effectiveness, successfully mitigating both device and artificially introduced SFO to achieve stable 60-GBaud transmission at 0.32-THz. This implementation establishes a record 576-Gb/s/<inline-formula><tex-math>$lambda$</tex-math></inline-formula> per-channel capacity while providing crucial insights into preventing artificial SFO in practical deployments. The work offers researchers essential tools for identifying and correcting human-induced sampling errors in next-generation THz systems.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"16 2","pages":"90-102"},"PeriodicalIF":3.9,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102996","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 : 2025-08-13DOI: 10.1109/TTHZ.2025.3598622
Lutfi Samara;Simon Haussmann;Erind Tufa;Antonio Alberto D'Amico;Tommaso Zugno;Ingmar Kallfass;Thomas Kürner
With global international mobile telecommunications (IMTs) traffic expected to grow 10–100 times from ITU-R 2015(as reported by ITU-R in 2015), the terahertz (THz) spectrum offers a promising solution to satisfy such forecasts. However, occupying the THz spectrum comes with its own challenges, an important one being impairments caused by broadband radio frequency components in THz transceivers. Nonlinearities in power amplifiers (PAs) complicate meeting link budget requirements, with amplitude and phase distortions degrading the system's performance, especially when adopting waveforms with high peak-to-average power ratios, such as orthogonal frequency division multiplexing. In this article, we present characterization results of a 300 GHz PA using small-signal and large-signal continuous-wave measurements. Models capturing amplitude-to-amplitude modulation and amplitude-to-phase modulation behavior across 270–330 GHz are developed and verified with wideband measurements, confirming the compression behavior, while nonetheless showing inaccuracies for low input powers due to unaccounted frequency dependencies. Based on the derived models, a predistortion algorithm is designed and analyzed, revealing significant error performance degradation when switching between single- and multicarrier waveforms. We finally show that an appropriate selection of predistorter parameters can significantly improve the performance.
{"title":"Sub-THz Power Amplifiers: Measurements, Behavioral Modeling, and Predistortion Algorithms","authors":"Lutfi Samara;Simon Haussmann;Erind Tufa;Antonio Alberto D'Amico;Tommaso Zugno;Ingmar Kallfass;Thomas Kürner","doi":"10.1109/TTHZ.2025.3598622","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3598622","url":null,"abstract":"With global international mobile telecommunications (IMTs) traffic expected to grow 10–100 times from ITU-R 2015(as reported by ITU-R in 2015), the terahertz (THz) spectrum offers a promising solution to satisfy such forecasts. However, occupying the THz spectrum comes with its own challenges, an important one being impairments caused by broadband radio frequency components in THz transceivers. Nonlinearities in power amplifiers (PAs) complicate meeting link budget requirements, with amplitude and phase distortions degrading the system's performance, especially when adopting waveforms with high peak-to-average power ratios, such as orthogonal frequency division multiplexing. In this article, we present characterization results of a 300 GHz PA using small-signal and large-signal continuous-wave measurements. Models capturing amplitude-to-amplitude modulation and amplitude-to-phase modulation behavior across 270–330 GHz are developed and verified with wideband measurements, confirming the compression behavior, while nonetheless showing inaccuracies for low input powers due to unaccounted frequency dependencies. Based on the derived models, a predistortion algorithm is designed and analyzed, revealing significant error performance degradation when switching between single- and multicarrier waveforms. We finally show that an appropriate selection of predistorter parameters can significantly improve the performance.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 6","pages":"1007-1019"},"PeriodicalIF":3.9,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435690","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 : 2025-08-13DOI: 10.1109/TTHZ.2025.3598719
Amar Al-jzari;Yubei He;Jiahao Hu;Sana Salous
The subterahertz and terahertz (THz) frequency bands are considered promising spectrum bands for 6G wireless systems due to the extensive available bandwidth. However, the radio channel in these frequency bands has not been thoroughly investigated in different scenarios using the same channel sounder. In this article, we present the results of measurements in around the 300 GHz band in both indoor and outdoor environments using the custom-designed Durham University chirp channel sounder. The results of channel characteristics, including the power delay profile, the root-mean-square delay, the K factor, the coherence bandwidth, and the path loss, are presented to assess the design of future radio networks in the THz bands.
{"title":"Sub-THz and THz Channel Measurements and Characteristic Analysis in Indoor and Outdoor Environments for 6G Wireless Systems","authors":"Amar Al-jzari;Yubei He;Jiahao Hu;Sana Salous","doi":"10.1109/TTHZ.2025.3598719","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3598719","url":null,"abstract":"The subterahertz and terahertz (THz) frequency bands are considered promising spectrum bands for 6G wireless systems due to the extensive available bandwidth. However, the radio channel in these frequency bands has not been thoroughly investigated in different scenarios using the same channel sounder. In this article, we present the results of measurements in around the 300 GHz band in both indoor and outdoor environments using the custom-designed Durham University chirp channel sounder. The results of channel characteristics, including the power delay profile, the root-mean-square delay, the K factor, the coherence bandwidth, and the path loss, are presented to assess the design of future radio networks in the THz bands.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 6","pages":"976-984"},"PeriodicalIF":3.9,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435692","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}
We report on the design, fabrication, and measurements of a solid-state frequency tripler with an output power > 100 mW above 300 GHz at room temperature. This tripler benefits from balanced face-to-face differential topology and improved diode configuration, providing quadruple power handling capabilities and excellent multiplication efficiency compared to traditional approaches. The improved diode configuration features a novel dual-row 12-anode architecture and has been integrated with peripheral circuit by terahertz monolithic integrated circuit process. At room temperature, the fabricated tripler demonstrates an average output power exceeding 82 mW and a corresponding conversion efficiency over 13.7% for a nominal input power of around 500–800 mW across 300–330 GHz band. Prominently, this tripler can deliver an ultra-high output power > 100 mW and an average efficiency >17% in the 306–317 GHz range, with a maximum power of 112.7 mW and a peak conversion efficiency of 19% for a 592-mW input power at 310.5 GHz.
{"title":"A 300–330 GHz Frequency Tripler With >100 mW Output and >17% Efficiency Based on Face-to-Face Topology and Enhanced Diode Configuration","authors":"Xiaojian Zhang;Qiyu Chen;Yue He;Zejia Deng;Yaoling Tian;Lingfeng Kang;Ruoxue Li;Ge Liu;Xiaochi Lu;Hao Yang;Ren Zhou;Jianping Zeng;Jun Jiang","doi":"10.1109/TTHZ.2025.3597197","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3597197","url":null,"abstract":"We report on the design, fabrication, and measurements of a solid-state frequency tripler with an output power > 100 mW above 300 GHz at room temperature. This tripler benefits from balanced face-to-face differential topology and improved diode configuration, providing quadruple power handling capabilities and excellent multiplication efficiency compared to traditional approaches. The improved diode configuration features a novel dual-row 12-anode architecture and has been integrated with peripheral circuit by terahertz monolithic integrated circuit process. At room temperature, the fabricated tripler demonstrates an average output power exceeding 82 mW and a corresponding conversion efficiency over 13.7% for a nominal input power of around 500–800 mW across 300–330 GHz band. Prominently, this tripler can deliver an ultra-high output power > 100 mW and an average efficiency >17% in the 306–317 GHz range, with a maximum power of 112.7 mW and a peak conversion efficiency of 19% for a 592-mW input power at 310.5 GHz.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"16 1","pages":"42-53"},"PeriodicalIF":3.9,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778402","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 : 2025-08-08DOI: 10.1109/TTHZ.2025.3597269
Brett N. Carnio;Grace S. Ciarniello;Oussama Moutanabbir;Abdulhakem Y. Elezzabi
A new approach to electro-optic (EO) detection is demonstrated through a novel geometry, whereby the probe and terahertz electric fields propagate in opposite directions. Theoretical analyses and experimental measurements are performed using a representative ZnGeP2 crystal implemented within this backward EO detection configuration. The backward EO detection signals encompass frequencies within a narrow spectral band of a few hundred gigahertz, tunable from ∼0.6–2.4 THz through adjustment of the incidence angle of the electric fields relative to the EO crystal. This novel arrangement provides EO detection with new phase-matching possibilities and offers a powerful tool for narrow-band spectroscopy.
{"title":"Backward Electro-Optic Detection for Narrowband Terahertz Time-Domain Spectroscopy","authors":"Brett N. Carnio;Grace S. Ciarniello;Oussama Moutanabbir;Abdulhakem Y. Elezzabi","doi":"10.1109/TTHZ.2025.3597269","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3597269","url":null,"abstract":"A new approach to electro-optic (EO) detection is demonstrated through a novel geometry, whereby the probe and terahertz electric fields propagate in opposite directions. Theoretical analyses and experimental measurements are performed using a representative ZnGeP<sub>2</sub> crystal implemented within this backward EO detection configuration. The backward EO detection signals encompass frequencies within a narrow spectral band of a few hundred gigahertz, tunable from ∼0.6–2.4 THz through adjustment of the incidence angle of the electric fields relative to the EO crystal. This novel arrangement provides EO detection with new phase-matching possibilities and offers a powerful tool for narrow-band spectroscopy.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"16 1","pages":"76-82"},"PeriodicalIF":3.9,"publicationDate":"2025-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778352","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 : 2025-08-07DOI: 10.1109/TTHZ.2025.3594233
Sara Vega;Garrit Schwanke;Simon Nellen;Sebastian Lauck;Martin Schell;Robert B. Kohlhaas;María Santos
The rapid expansion of wireless data communication and integrated sensing systems necessitates the development of advanced antenna technologies capable of operating at higher frequencies and bandwidths with dynamic beam management, specifically directional beam control. This article addresses the challenge by designing a wideband photonic switched-beam antenna consisting of a 1 × 4 array of broadband bowtie antenna elements (AEs) fed by PIN photodiodes (PDs) on an InP substrate. Additional semiconductor optical amplifiers (SOAs) enable selective activation of single elements. Beam switching is realized through a hyperhemispherical lens, where the beam pointing angle is determined by the offset distance of the active AE from the lens axis. Beam pattern measurements confirm clear beam switching behavior with good beam quality up to 300 GHz, and discernible radiation angles up to 2 THz, albeit with degraded beam shapes at the upper end of the spectrum. Our results prove the broadband capabilities of this approach, despite variations in beam quality across different offsets and frequencies. A developed theoretical model, based on subcritical angle incidence at the lens-air interface, accurately predicts the beam pointing angle of the prototype. Simulations have been employed to optimize the design of a 2-D antenna array operating at 100 GHz, providing full 3 dB beam coverage within a ±60° range. The presented results highlight the potential of photonic technologies to enable scalable and efficient beam management solutions for applications up to the terahertz frequency range.
{"title":"Subterahertz Photonic Switched-Beam Antenna With Up to 60° Tilt","authors":"Sara Vega;Garrit Schwanke;Simon Nellen;Sebastian Lauck;Martin Schell;Robert B. Kohlhaas;María Santos","doi":"10.1109/TTHZ.2025.3594233","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3594233","url":null,"abstract":"The rapid expansion of wireless data communication and integrated sensing systems necessitates the development of advanced antenna technologies capable of operating at higher frequencies and bandwidths with dynamic beam management, specifically directional beam control. This article addresses the challenge by designing a wideband photonic switched-beam antenna consisting of a 1 × 4 array of broadband bowtie antenna elements (AEs) fed by PIN photodiodes (PDs) on an InP substrate. Additional semiconductor optical amplifiers (SOAs) enable selective activation of single elements. Beam switching is realized through a hyperhemispherical lens, where the beam pointing angle is determined by the offset distance of the active AE from the lens axis. Beam pattern measurements confirm clear beam switching behavior with good beam quality up to 300 GHz, and discernible radiation angles up to 2 THz, albeit with degraded beam shapes at the upper end of the spectrum. Our results prove the broadband capabilities of this approach, despite variations in beam quality across different offsets and frequencies. A developed theoretical model, based on subcritical angle incidence at the lens-air interface, accurately predicts the beam pointing angle of the prototype. Simulations have been employed to optimize the design of a 2-D antenna array operating at 100 GHz, providing full 3 dB beam coverage within a ±60° range. The presented results highlight the potential of photonic technologies to enable scalable and efficient beam management solutions for applications up to the terahertz frequency range.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 6","pages":"1082-1091"},"PeriodicalIF":3.9,"publicationDate":"2025-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11119741","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435683","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 : 2025-08-04DOI: 10.1109/TTHZ.2025.3595809
Chunhui Li;Zhiqiang Yuan;Wei Fan
Subterahertz (sub-THz) technology, due to its abundant spectrum resources, is considered one of the key candidates for 6G communication and sensing systems. To facilitate the design of sub-THz systems, it is essential to evaluate the performance of sub-THz radios within realistic propagation environments in the laboratory. Channel emulator (CE), which can emulate radio channels between the transmitter and receiver, is a key instrument for wireless system air-interface testing. Sub-THz radio channel emulation faces many challenges due to hardware and resource limitation in the CE, e.g., the misalignment between the gridded tap delays in the CE and the arbitrary tap delays in simulated and measured channels, the limited number of tap delays in the CE, the limited system bandwidth and restricted system carrier frequency, and the nonideal frequency response over system band. In this article, we proposed a framework for emulating sub-THz channels that can simultaneously address tap delay misalignment, tap resource limitations, and radio frequency branch frequency response inconsistency during the band-stitching process. To efficiently perform sub-THz channel emulation, we also introduced several effective optimization methods to solve the problems formulated within the framework. To evaluate the effectiveness of the proposed framework, we carried out channel measurements at two frequency bands, i.e., 100 and 300 GHz in two representative scenarios. Moreover, we performed the channel emulation of the measured channel frequency responses over many spatial locations using the proposed framework. The numerical emulation results demonstrate the effectiveness and robustness of the proposed framework.
{"title":"Subterahertz Radio Channel Emulation With Band-Stitching Scheme: Framework, Resource Optimization, and Validation","authors":"Chunhui Li;Zhiqiang Yuan;Wei Fan","doi":"10.1109/TTHZ.2025.3595809","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3595809","url":null,"abstract":"Subterahertz (sub-THz) technology, due to its abundant spectrum resources, is considered one of the key candidates for 6G communication and sensing systems. To facilitate the design of sub-THz systems, it is essential to evaluate the performance of sub-THz radios within realistic propagation environments in the laboratory. Channel emulator (CE), which can emulate radio channels between the transmitter and receiver, is a key instrument for wireless system air-interface testing. Sub-THz radio channel emulation faces many challenges due to hardware and resource limitation in the CE, e.g., the misalignment between the gridded tap delays in the CE and the arbitrary tap delays in simulated and measured channels, the limited number of tap delays in the CE, the limited system bandwidth and restricted system carrier frequency, and the nonideal frequency response over system band. In this article, we proposed a framework for emulating sub-THz channels that can simultaneously address tap delay misalignment, tap resource limitations, and radio frequency branch frequency response inconsistency during the band-stitching process. To efficiently perform sub-THz channel emulation, we also introduced several effective optimization methods to solve the problems formulated within the framework. To evaluate the effectiveness of the proposed framework, we carried out channel measurements at two frequency bands, i.e., 100 and 300 GHz in two representative scenarios. Moreover, we performed the channel emulation of the measured channel frequency responses over many spatial locations using the proposed framework. The numerical emulation results demonstrate the effectiveness and robustness of the proposed framework.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 6","pages":"996-1006"},"PeriodicalIF":3.9,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435672","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 : 2025-08-04DOI: 10.1109/TTHZ.2025.3595812
Suprovo Ghosh;Haidong Guo;Frank Zhang;Kenneth K. O.
A 305-GHz power amplifier (PA) fabricated in a 130-nm SiGe HBT BiCMOS technology with HBT $f_{t}/ f_{text{max}}= 350/ 450,text{GHz}$ and Aluminum metallization is presented. The PA employs four-way combined four pseudo-differential cascode amplification stages with a capacitive feedback network between the collector of common base stage and the base of common emitter stage that counters the gain degradation by neutralizing the input loss and capacitance of common emitter stage resulting from the device parasitics, transit time related phase delay effects and the interconnect inductances in the layout especially due to the unavoidable interconnect between the output of common-emitter and input of the common-base stage. The PA achieves a measured $P_{text{sat}}$ of 8.3 dBm, $OP_{mathrm{1dB}}$ of 6 dBm, and a peak small signal gain of 14.5 dB at 305 GHz while consuming 880 mW of dc power from a 4-V supply. The PA exhibits the highest $P_{text{sat}}$, $OP_{mathrm{1dB}}$, and the highest small signal gain at 305 GHz among the PA's fabricated using SiGe HBT's with $f_{text{max}}$ less than 500 GHz.
{"title":"305-GHz Cascode SiGe HBT Power Amplifier With L-C Feedback Achieving Psat of 8.3 dBm","authors":"Suprovo Ghosh;Haidong Guo;Frank Zhang;Kenneth K. O.","doi":"10.1109/TTHZ.2025.3595812","DOIUrl":"https://doi.org/10.1109/TTHZ.2025.3595812","url":null,"abstract":"A 305-GHz power amplifier (PA) fabricated in a 130-nm SiGe HBT BiCMOS technology with HBT <inline-formula><tex-math>$f_{t}/ f_{text{max}}= 350/ 450,text{GHz}$</tex-math></inline-formula> and Aluminum metallization is presented. The PA employs four-way combined four pseudo-differential cascode amplification stages with a capacitive feedback network between the collector of common base stage and the base of common emitter stage that counters the gain degradation by neutralizing the input loss and capacitance of common emitter stage resulting from the device parasitics, transit time related phase delay effects and the interconnect inductances in the layout especially due to the unavoidable interconnect between the output of common-emitter and input of the common-base stage. The PA achieves a measured <inline-formula><tex-math>$P_{text{sat}}$</tex-math></inline-formula> of 8.3 dBm, <inline-formula><tex-math>$OP_{mathrm{1dB}}$</tex-math></inline-formula> of 6 dBm, and a peak small signal gain of 14.5 dB at 305 GHz while consuming 880 mW of dc power from a 4-V supply. The PA exhibits the highest <inline-formula><tex-math>$P_{text{sat}}$</tex-math></inline-formula>, <inline-formula><tex-math>$OP_{mathrm{1dB}}$</tex-math></inline-formula>, and the highest small signal gain at 305 GHz among the PA's fabricated using SiGe HBT's with <inline-formula><tex-math>$f_{text{max}}$</tex-math></inline-formula> less than 500 GHz.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"16 1","pages":"54-67"},"PeriodicalIF":3.9,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778384","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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