[paper] THz Measurements, Antennas, and Simulations

Fawad Sheikh 1, Andreas Prokscha 1, Johannes M. Eckhardt 2, Tobias Doeker 2, Naveed A. Abbasi 3, Jorge Gomez-Ponce 3,4, Benedikt Sievert 5, Jan Taro Svejda 5, Andreas Rennings 5, Jan Barowski 6, Christian Schulz 6, Ilona Rolfes 6, Daniel Erni 5, Andreas F. Molisch 3, Thomas Kürner 2, and Thomas Kaiser 1

THz Measurements, Antennas, and Simulations: From the Past to the Future

Invited Paper in IEEE Journal of Microwaves, vol. 3, no. 1, pp. 289-304, Jan. 2023

DOI: 10.1109/JMW.2022.3216210

1 Institute of Digital Signal Processing, UDE, Duisburg (D)

2 Institute for Communications Technology, TU Braunschweig (D)

3 Wireless Devices and Systems Group, University of Southern California, Los Angeles (USA) 
4 ESPOL, Facultad de Ingeniería en Electricidad y Computación, Guayaquil (EC)
5 ATE, University of Duisburg-Essen, and CENIDE Duisburg (D)
6 Institute of Microwave Systems, Ruhr University, Bochum (D)

Abstract: In recent years, terahertz (THz) systems have become an increasingly popular area of research thanks to their unique properties such as extremely high data rates towards Tb/s, submillimeter localization accuracy, high resolution remote sensing of materials, and remarkable advances in photonics and electronics technologies. This article traces the progress of the THz measurements, antennas and simulations, from historical milestones to the current state of research and provides an outlook on the remaining challenges.

FIG: Realized gain measurement of the integrated antenna prototype compared to the estimation of the corresponding equivalent circuit (EC) model in E- and H-plane at 290GHz (a)

and micrograph of the antenna prototype (b)

Acknowledgment: This work was supported in part by Deutsche Forschungsgemeinschaft for Projects M01, M02, M03, M04, C05, and S03, under Project 287022738 TRR 196, in part by the Ministry of Culture and Science of the State of North Rhine-Westphalia (MKW NRW) through Project terahertz.NRW, and in part by the Open Access Publication Fund of the University of Duisburg-Essen. The work of Jorge Gomez-Ponce was supported by Foreign Fulbright Ecuador SENESCYT Program. The work of Johannes M. Eckhardt, Tobias Doeker, and Thomas Kürner was supported in part by the Federal Ministry of Education and Research (BMBF), Germany, through 6G Research and Innovation Cluster 6G-RIC under Grant 16KISK031 and in part by German Research Foundation (DFG) under Grant FOR 2863, “Meteracom - Metrology for THz Communications.” The work of Jorge Gomez-Ponce, Naveed A. Abbasi, and Andreas F. Molisch was supported by SRC, DARPA, NSF, NIST, and Samsung Research America through ComSenTer Program. This work did not involve human subjects nor animals in its research.

[paper] Sub-THz HICUM for SiGe HBTs

Soumya Ranjan Panda, Thomas Zimmer, Anjan Chakravorty, Nicolas Derrier

and Sebastien Fregonese

Exploring Compact Modeling of SiGe HBTs in Sub-THz Range With HICUM

in IEEE TED, DOI: 10.1109/TED.2023.3321017.

IMS laboratory, CNRS, University of Bordeaux (F)
Department of Electrical Engineering, IIT Madras (IN)
STMicroelectronics, 38920 Crolles (F)

Abstract : This study delves deeper into the high frequency (HF) behavior of state-of-the-art sub-THz silicon germanium heterojunction bipolar transistors (SiGe HBTs) fabricated with 55 nm BiCMOS process technology from STM. Using measurement data, calibrated TCAD simulations, and compact model simulations, we present a comprehensive methodology for extracting several HF parameters (related to parasitic capacitance partitioning and nonquasi-static effects) of the industry standard model, HICUM. The parameter extraction strategies involve thorough physics-based investigation and sensitivity analysis. The latter allowed us to precisely evaluate the effects of parameter variations on frequency dependent characteristics. The accuracy of the finally deployed model is tested by comparing the model simulation with measured small-signal two-port parameters of SiGe HBTs up to 330 GHz.

FIG: a.)  TEM image of the SiGe HBT device; b.) 2D TCAD structure simulation; c.) Large signal equivalent circuit of HICUM L2 compact model; d.) and e.) adjunct networks for vertical NQS effects

Acknowledgment: The authors would like to acknowledge Dider Celi, STM, for valuable discussion about the compact modeling of heterojunction bipolar transistors (HBTs), and they also like to thank STM for providing the silicon wafers. This work was supported by NANO2022 Important Project of Common European Interest Project (IPCEI), and SHIFT Grant ID 101096256.

[paper] THz FET Modeling

Adam Gleichman¹, Kindred Griffis¹, and Sergey V. Baryshev^1,2

Useful Circuit Analogies to Model THz Field Effect Transistors

arXiv:2307.07488v1 [physics.app-ph] 14 Jul 2023

1) Department of Electrical and Computer Engineering, Michigan State University, USA
2) Department of Chemical Engineering and Materials Science, Michigan State University, USA

Anstract: The electron fluid model in plasmonic field effect transistor (FET) operation is related to the behavior of a radio-frequency (RF) cavity. This new understanding led to finding the relationships between physical device parameters and equivalent circuit components in traditional parallel resistor, inductor, and capacitor (RLC) and transmission models for cavity structures. Verification of these models is performed using PSpice to simulate the frequency dependent.

FIG: RLC Lumped THz FET Model

[paper] Multi-Segment TFT Compact Model for THz Applications

Xueqing Liu¹,Trond Ytterdal² and Michael Shur^1,3

Multi-Segment TFT Compact Model for THz Applications

Nanomaterials 2022, 12(5), 765; 

DOI: 10.3390/nano12050765

  
1 RPI, Troy, NY 12180, USA
2 Norwegian University of Science and Technology, Trondheim, Norway
3 Electronics of the Future, Inc., USA

Abstract: We present an update of the Rensselaer Polytechnic Institute (RPI) thin-film transistor (TFT) compact model. The updated model implemented in Simulation Program with Integrated Circuit Emphasis (SPICE) accounts for the gate voltage-dependent channel layer thickness, enables the accurate description of the direct current (DC) characteristics, and uses channel segmentation to allow for terahertz (THz) frequency simulations. The model introduces two subthreshold ideality factors to describe the control of the gate voltage on the channel layer and its effect on the drain-to-source current and the channel capacitance. The calculated field distribution in the channel is used to evaluate the channel segment parameters including the segment impedance, kinetic inductance, and gate-to-segment capacitances. Our approach reproduces the conventional RPI TFT model at low frequencies, fits the measured current–voltage characteristics with sufficient accuracy, and extends the RPI TFT model applications into the THz frequency range. Our calculations show that a single TFT or complementary TFTs could efficiently detect the sub-terahertz and terahertz radiation.

FIG: (a) quivalent circuit of the multi-segment SPICE model for TFT and
(b) equivalent circuit for each segment including leakage components

Acknowledgements: The work was supported by Office of Naval Research (N000141712976, Project Monitor Paul Maki).

[paper] Ultrafast imaging of THz electric waveforms using quantum dots

Moritz B. Heindl, Nicholas Kirkwood, Tobias Lauster, Julia A. Lang, Markus Retsch, Paul Mulvaney and Georg Herink;

Ultrafast imaging of terahertz electric waveforms using quantum dots;

Light: Science & Applications; Vol. 11, No. 5 (2022)

DOI: 10.1038/s41377-021-00693-5

Abstract: Microscopic electric fields govern the majority of elementary excitations in condensed matter and drive electronics at frequencies approaching the Terahertz (THz) regime. However, only few imaging schemes are able to resolve sub-wavelength fields in the THz range, such as scanning-probe techniques, electro-optic sampling, and ultrafast electron microscopy. Still, intrinsic constraints on sample geometry, acquisition speed and field strength limit their applicability. Here, we harness the quantum-confined Stark-effect to encode ultrafast electric near-fields into colloidal quantum dot luminescence. Our approach, termed Quantum-probe Field Microscopy (QFIM), combines far-field imaging of visible photons with phase-resolved sampling of electric waveforms. By capturing ultrafast movies, we spatio-temporally resolve a Terahertz resonance inside a bowtie antenna and unveil the propagation of a Terahertz waveguide excitation deeply in the sub-wavelength regime. The demonstrated QFIM approach is compatible with strong-field excitation and sub-micrometer resolution introducing a direct route towards ultrafast field imaging of complex nanodevices in-operando.

Fig: Quantum-Probe Field Microscopy (QFIM): a.) Imaging of THz electric near-fields in a fluorescence microscope using quantum dot (QD) luminescence. The absorption of ultrashort visible sampling pulses (green) is modulated via the quantum-confined Stark effect in a layer of nanocrystals (red); b.) The THz-induced change in the QD band structure can increase the absorption and translates to enhanced luminescence emission, accessible by optical microscopy. The modulated fluorescence yield SQFIM = STHz−S0 encodes the instantaneous local electric field and snapshot images resolve the spatio-temporally evolution of the near-field waveform

Acknowledgements: We [the authors] thank J. Koehler and M. Lippitz for experimental equipment and valuable discussions. This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) via project 403711541. T.L. acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research program (grant agreement no. 714968). N.K. and P.M. thank the ARC for support through grant CE170100026. Open Access funding enabled and organized by Projekt DEAL.

Advances in RF and THz emerging electronic devices webinar at IPN-UAB

The webinar joitly co-organize together with Instituto Politécnico Nacional, Mexico 

is intended to present and discuss recent advances in RF and THz emerging electronic devices.

Feel free to share the information with your colleagues and/or students. The registration is free, and you can do it here (it is in Spanish but the only required fields are Name, Surname, Email, and Email confirmation). Alternatively, you can follow the live stream in this youtube channel.

The time appearing in the flyers are referred to Mexico City's time. The schedule is starting each day Nov.16-18, 2021 at 16 hrs CET.

If you have further questions you can contact 

• Aníbal Uriel Pacheco Sanchez or 
• Eloy Ramirez Garcia, IPN co-organizer

   

[paper] TFETs for sensitive THz detection

I. Gayduchenko^1,2, S.G. Xu^3,4, G. Alymov¹, M. Moskotin^2,1, I. Tretyakov⁵, T. Taniguchi⁶, K.Watanabe⁷, G. Goltsman⁸, A.K. Geim^3,4, G. Fedorov^1,2, D. Svintsov¹, and D.A. Bandurin^3,1

Tunnel field-effect transistors for sensitive terahertz detection

arXiv:2010.03040 (2020)

¹Moscow Institute of Physics and Technology (National Research University), Dolgoprudny 141700, Russia
²Physics Department, Moscow Pedagogical State University, Moscow, 119435, Russia
³School of Physics, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
⁴National Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom
⁵Astro Space Center, Lebedev Physical Institute of the Russian Academy of Sciences, Moscow 117997, Russia
⁶International Center for Materials Nanoarchitectonics, National Institute of Material Science, Tsukuba 305-0044, Japan
⁷Research Center for Functional Materials, National Institute of Material Science, Tsukuba 305-0044, Japan
⁸National Research University Higher School of Economics, Moscow, 101000, Russia

Abstract: The rectification of high-frequency electromagnetic waves to direct currents is a crucial process for energy harvesting, beyond 5G wireless communications, ultra-fast science, and observational astronomy. As the radiation frequency is raised to the sub-terahertz (THz) domain, efficient ac-to-dc conversion by conventional electronics becomes increasingly challenging and requires alternative rectification protocols. Here we address this challenge by tunnel field-effect transistors made of dual-gated bilayer graphene (BLG). Taking advantage of BLG’s electrically tunable band structure, we create a lateral tunnel junction and couple it to a broadband antenna exposed to THz radiation. The incoming radiation is then down-converted by strongly non-linear interband tunneling mechanisms, resulting in exceptionally high-responsivity (exceeding 3kV/W) and low-noise (0.2pW/Hz−−−√)  detection at cryogenic temperatures. We demonstrate how the switching from intraband Ohmic to interband tunneling regime within a single detector can raise its responsivity by one order of magnitude, in agreement with the developed theory. Our work demonstrates an unexpected application of interband tunnel transistors for high-frequency detection and reveals bilayer graphene as one of the most promising platforms therefor.

Fig: Overview of THz detectors. NEP for THz detectors of various types plotted against the temperature at which they operate. Vertical error bars represent the spread of the detectors’ performance over the frequency range 0.1−2 THz. Horizontal error bars show the temperature range at which the detectors operate.  

Acknowledgements: This work was supported by the Russian Foundation for Basic Research within Grants No. 18-37-20058 and No. 18-29-20116. Experimental work of IG (photoresponse measurements) was supported by the Russian Foundation for Basic Research (grant 19-32-80028). We acknowledge support of the Russian Science Foundation grant No. 19-72-10156 (NEP analyses) and grant No.17-72-30036 (transport measurements). The work of GA and DS (theory of THz detection) was supported by grant # 16-19-10557 of the Russian Scientific Foundation. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan, Grant Number JPMXP0112101001, JSPS KAKENHI Grant Number JP20H00354 and the CREST(JPMJCR15F3), JST. The authors thank A. Lisauskas, W. Knap, A. I. Berdyugin and M.S. Shur for helpful discussions.

IRPhE 2020 Aghveran, Armenia

International Conference on Microwave & THz Technologies,

Wireless Communications and OptoElectronics

September 23-25, 2020, Aghveran, Armenia

IRPhE 2020 Call for Papers

The aim of the IRPhE’ 2020 Conference is to provide an open forum for the presentation and discussion of current research in Microwave and THz technologies, wireless communications, alternative electronic devices, photonics and its applications.

The main topics of the conference are and not limited to:

• Microwave devices, antennas, propagation and remote sensing
• THz technique, spectroscopy and applications
• Alternative semiconductor and dielectric materials, electronic devices
• Wireless communications and related information technologies
• Microwave photonics

For further information visit the website: http://www.irphe.am/?q=conference

Submission Information

Original one page abstracts will be accepted for review in Word and PDF formats.The accepted abstracts will be published in an abstract book and distributed during the conference.

All the authors who have presented their work at the conference will be invited to submit 4-page follow-up papers for publication special IJHSES issue on the "Microwave and THz technologies"

Abstracts must be submitted via email: science@irphe.am.