| 1. |
- Svedin, Jan, et al.
(författare)
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Development of a 210 GHz near-field measurement radar system based on an antenna-integrated MMIC receiver front-end and an ultra-compact HBV transmitter source module
- 2008
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819473493 ; 7117, s. Art. no. 71170H-
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Konferensbidrag (refereegranskat)abstract
- The development of a 210 GHz radar system intended to study security applications such as personnel scanning is reported. The system is designed to operate with a transmit antenna floodlighting the target scene and a mechanically scanned antenna-integrated receiver module. For increased performance and potential future volume production the receiver front-end is based on highly integrated MMICs manufactured using the IAF 0.1 µm GaAs mHEMT process made available through a Swedish-German MoU. A single-chip MMIC solution is being developed containing feed antenna, LNA, mixer and an LO multiplier-chain. The transmitter part is based on a high-power HBV quintupler source-module.
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| 2. |
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| 3. |
- Banik, Biddut Kumar, 1978, et al.
(författare)
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Development and Design of a 340 GHz Photomixer Source
- 2007
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Ingår i: 18th International Symposium on Space THz Technology – ISSTT 2007.
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Konferensbidrag (refereegranskat)abstract
- We present the design of an InGaAlAs/InP uni-traveling-carrier photo-diode (UTC-PD) at mm-wave frequencies up to 340 GHz. The photo diode epitaxy is optimized using a quasi-3D software implementing the hydrodynamic semiconductor equations, for which an output power of 3 mW at 340 GHz was simulated. An equivalent circuit of the UTC-PD has been fitted to experimental S11 measurements up to 67 GHz. Finally, an optimized antenna coupled UTC-PD with choke filter has been designed. This MMIC circuit is intended for photomixing, with output power at 340 GHz.
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| 4. |
- Banik, Biddut Kumar, 1978, et al.
(författare)
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High Power Photonic MW/THz Generation Using UTC-PD
- 2008
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Ingår i: GigaHertz SympoSium 2008. ; , s. 45-
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Konferensbidrag (refereegranskat)abstract
- The ongoing research work concentrates on extending the previously accomplished UTC-PD fabrication and modelling techniques to 340 GHz and above. We have fabricated and characterized UTC-PDs intended for high power MW/THz generation. Several integrated antenna-detector circuits have been designed and characterised.
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| 5. |
- Banik, Biddut Kumar, 1978, et al.
(författare)
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UTC-PD Integration for Submillimetre-wave Generation
- 2008
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Ingår i: 19th International Symposium on Space Terahertz Technology, ISSTT 2008; Groningen; Netherlands; 28 April 2008 through 30 April 2008. ; , s. P7-1, 135
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Konferensbidrag (refereegranskat)abstract
- Because of the inherent difficulty to generate power in the frequency range 0.l-10 THz, the term 'THzgap' has been coined. Among a number of MW/THz generation techniques, the photomixer based sources hold high potential offering wide tunability and decent amounts of output power. The photomixing technique relies on the nonlinear mixing of two closely spaced laser wavelengths generating a beat oscillation at the difference frequency. In recent years, there has been an increasing interest in the Uni-Travelling-Carrier PhotoDiode (UTCPD) [1] for photomixing, photo receivers, MW/THz-wave generation, fibre-optic communication systems, and wireless communications. UTC-PDs have become very promising by demonstrating output powers of 20 mW at 100 GHz [1] and 25 μW at 0.9 THz [2].
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| 6. |
- Bryllert, Tomas, 1974, et al.
(författare)
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220-GHz imaging radar with 1 Hz frame rate using an array of homodyne transceivers
- 2018
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 10634
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Konferensbidrag (refereegranskat)abstract
- We present a 220 GHz imaging radar prototype that has been developed in the European Defense Agency (EDA) project TIPPSI. The purpose of the development was to demonstrate short-range high-resolution 3D imaging for security applications at checkpoints, and to guide the development of stand-off real-time millimeter wave and sub-millimeter wave imaging systems for detection of larger objects at greater distances. An additional goal was to experimentally verify simulation techniques for active (sub)-mmw imaging systems, the verified simulation techniques can then be used to explore different system architectures. The 220 GHz imaging radar prototype consist of a flexible, mechanically scanned optical system that can support linear arrays of transmit/receive (TxRx) units up to 150 mm in length. The optical system is divided into two parts: A compact Dragonian system including the mechanical scanner that can be used as a stand-alone imager at reduced target distance and resolution, and a confocal system that can be added to achieve the full resolution of 1 cm x 1 cm x 1 cm at 4.5 m target distance. The field of view of the full resolution system is 70 cm x 70 cm. The front-end is currently populated by 4 TxRx units that are sparsely distributed along the 150 mm focal plane. The TxRx units operate in frequency modulated continuous wave (FMCW) mode and have a bandwidth of 24 GHz. Each TxRx unit use a single horn antenna and the transmit- and receive signals are generated and received using the same circuits which avoids the need of a duplexer. We will demonstrate high resolution 3D videos taken at 1 Hz frame rate and compare the individual images with simulations using electromagnetic simulators and character/clothes animation.
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| 7. |
- Fobelets, Kristel, et al.
(författare)
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High-frequency capacitance of bipolar resonant tunneling diodes
- 1996
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 79:2, s. 905-910
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Tidskriftsartikel (refereegranskat)abstract
- The high-frequency characteristics of bipolar resonant tunneling diodes are experimentally investigated at room temperature. The electron accumulation and discharging in these resonant tunneling light-emitting diodes are studied at frequencies up to 35 GHz. The experiments show capacitance peaks due to electron charge disappearing from the quantum well. The measurements are found to be in agreement with our theoretical model for the calculation of the high-frequency characteristics of resonant tunneling devices. The high-frequency characteristics of the bipolar light-emitting resonant tunneling diode are compared to the unipolar resonant tunneling diode and the resonant interband tunneling diode. The comparison shows a similar discharging characteristic of the quantum well, but a different overall variation of the capacitance.
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| 8. |
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| 9. |
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| 10. |
- Majdi, Saman, 1977-, et al.
(författare)
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Enhanced Hall mobility in graphene-on-electronic-grade diamond
- 2023
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 123:1
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Tidskriftsartikel (refereegranskat)abstract
- The outstanding electronic properties of graphene make this material a candidate for many applications, for instance, ultra-fast transistors. However, self-heating and especially the detrimental influence of available supporting substrates have impeded progress in this field. In this study, we fabricate graphene-diamond heterostructures by transferring graphene to an ultra-pure single-crystalline diamond substrate. Hall-effect measurements were conducted at 80 to 300 K on graphene Hall bars to investigate the charge transport properties in these devices. Enhanced hole mobility of 2750 cm(2) V-1 s(-1) could be observed at room-temperature when using diamond with reduced nitrogen (N-s(0)) impurity concentration. In addition, by electrostatically varying the carrier concentration, an upper limit for mobility is determined in the devices. The results are promising for enabling carbon-carbon (C-C) devices for room-temperature applications.
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| 11. |
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| 12. |
- Sobis, Peter, 1978, et al.
(författare)
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SWI 1200/600 GHz highly integrated receiver front-ends
- 2015
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Ingår i: 36th ESA Antenna Workshop on Antennas and RF Systems for Space Science, ESA/ESTEC ,Noordwijk, The Netherlands; 6-9 Oct. 2015. ; session S3.1.2
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Konferensbidrag (refereegranskat)
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| 13. |
- Sobis, Peter, 1978, et al.
(författare)
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Ultra Low Noise 600/1200 GHz and 874 GHz GaAs Schottky Receivers for SWI and ISMAR
- 2016
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Ingår i: Twenty-seventh International Symposium on Space Terahertz Technology (ISSTT).
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Konferensbidrag (refereegranskat)abstract
- Omnisys Instruments is responsible for the 600/1200 GHz broadband front-end receivers and back-end spectrometer hardware for the Submillimeter Wave Instrument (SWI) part of the Jupiter Icy moons Explorer (JUICE) mission, and for the development of the dual-polarization 874 GHz spectrometer channels for the airborne icecloud imager instrument ISMAR. We will present our development of these highly integrated heterodyne receivers which are based on membrane integrated GaAs Schottky diode mixer and multiplier circuit technology, and InP HEMT MMIC LNA technology from Chalmers University of Technology. Preliminary results at room temperature on the 1200 GHz breadboard prototypes show on a typical DSB receiver noise below 3000 K in the 1030 GHz-1220 GHz frequency range with only 1-3 mW of LO power. For the 874 GHz receiver flight modules a record low double sideband noise of 2500 K was obtained with only 2.3 mW of LO pump power. Both the 1200 GHz and 874 GHz subharmonically pumped Schottky mixer designs have been based on the broadband SWI 600 GHz channel mixer design, which had a repeatable receiver noise performance below 1200K with less than 2 mW of pump power at room temperature. All together these results are setting new standards for critical receiver hardware operating at room temperature used in instrumentation for atmospheric research and remote sensing applications.
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| 14. |
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| 15. |
- Svedin, Jan, et al.
(författare)
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An experimental 210 GHz radar system for 3D stand-off detection
- 2010
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Ingår i: 35th International Conference on Infrared Millimeter and Terahertz Waves (IRMMW-THz), 2010. - 9781424466559
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Konferensbidrag (refereegranskat)abstract
- A 210 GHz radar system for studies of personscanning at stand-off distances is presented. The radar uses amechanically scanned RX front-end based on an antennaintegratedMMIC. The TX part is based on an HBV quintupler.Image data formation is made using the FMCW and SARprinciples.
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| 16. |
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| 17. |
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| 18. |
- Tavakoli Dastjerdi, Mohammad Hadi, 1984, et al.
(författare)
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InGaAs/InAlAs/AlAs Heterostructure Barrier Varactors on Silicon Substrate
- 2011
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 32:2, s. 140-142
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of a study on epitaxial transferof InP-based heterostructure barrier varactor (HBV) materials onto a silicon substrate employing the low-temperature plasma activated bonding technique. The test diodes fabricated on the bonded samples exhibit symmetric electrical characteristics, over the temperature range of 25 ˚C–165 ˚C, and show no degradation compared to previously reported InP-based diodes. Moreover, the onset temperature for debonding, the effective barrier height extracted from the measured data, and the maximum voltage of the HBVs for a current density of 100 A/cm2 were extracted to be 260 ˚C, 0.56 eV, and 10.5 V, respectively.
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| 19. |
- Tavakoli Dastjerdi, Mohammad Hadi, 1984, et al.
(författare)
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Transfer of InP-based HBV epitaxy onto borosilicate glass substrate by anodic bonding
- 2010
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 46:14, s. 1013-1014
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Tidskriftsartikel (refereegranskat)abstract
- We present a new fabrication process for epitaxial transfer of InP-based heterostructure barrier varactor diodes, as high frequency varactor multipliers, onto low-dielectric borosilicate glass substrate, employing anodic bonding. The fabricated diodes on the new host substrate display symmetric electrical characteristics with only minor differences compared to those of the reference devices on the original InP substrate.
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| 20. |
- Vukusic, Josip, 1972, et al.
(författare)
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Development of Uni-Travelling-Carrier Photodiodes
- 2006
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Ingår i: 4th ESA Workshop on Millimetre Wave Technology and Applications.
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Konferensbidrag (refereegranskat)abstract
- We have fabricated and characterized InGaAsP/InP uni-travelling-carrier photodiodes (UTC-PDs). An UTC-PD layer structure in the material system InGaAlAs/InP was also designed and grown with in-house molecular beam epitaxy (MBE). Using standard III-V processing involving lithography, metallization and etching, diodes of different sizes have been fabricated. Time domain and eye-diagram measurements have been performed. Limitations in the measurement system were identified and compensated for when measuring the bandwidth. The resulting bandwidth is in agreement with the area dependent RC-limitation which was estimated using quasi-DC capacitance-voltage (C-V) measurements.
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| 21. |
- Vukusic, Josip, 1972, et al.
(författare)
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Fabrication and Characterization of InGaAlAs/InP based Uni-Traveling-Carrier Photodiodes
- 2006
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Ingår i: The Joint 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics. - 1424404002 ; , s. 138-
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Konferensbidrag (refereegranskat)abstract
- We have fabricated and characterized InGaAlAs/InP uni-traveling-carrier photodiodes intended for photo-mixing and data-com applications. Bandwidths up to 60GHz were recorded with 8.5µm diameter devices for which a matched, integrated antenna-detector circuit has been designed.
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| 22. |
- Wiberg, Andreas, 1978, et al.
(författare)
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Characterization of uni-traveling carrier photodiodes for high-linearity and high-SNR applications
- 2010
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Ingår i: Microwave and Optical Technology Letters. - : Wiley. - 1098-2760 .- 0895-2477. ; 52:6, s. 1460-1460
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Tidskriftsartikel (refereegranskat)abstract
- A typical uni-traveling carrier photodiode (UTC-PD) and a commercial PIN-PD are compared in the context of the analog performance at 10 GHz in a realistic noise environment.The behavior of the carrier-to-noise ratio (CNR), the linearity, represented by the third-order output intercept point (OIP3), and the spurious free dynamic range are studied as a function of photocurrent. We have found that the increment of the CNR is only minor because of excess noise of the amplifier, as an optical amplifier is used to reach high optical power. However, the OIP3 of the UTC-PD is substantially higher and increases with photocurrent, in contrast to the PIN-PD. Thus, even though the responsivity is lower, it is beneficial to use a UTC-PD to have superior dynamic range.
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| 23. |
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Abstract Book of the 30th Workshop on Compound Semiconductor Devices and Integrated Circuits in Europe
- 2006
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- The organisers and hosts warmly welcome you to the 30th Workshop on Compound Semiconductor Devices and Integrated Circuits in Europe, WOCSDICE 2006, at the Gullmarsstrand Hotel & Conferences in Fiskebäckskil, Sweden, May 14-17, 2006. The symposium is organised by the Chalmers Department of Microtechnology and Nanoscience (MC2) with the aim to create a forum where researchers can discuss latest results and trends in the field of compound semiconductor technology and related science. Established in 1973, WOCSDICE has a long-standing tradition. This workshop brings together both internationally recognised researchers and promising young scientists and engineers to disseminate state-of-the-art research findings in the areas of compound semiconductor materials, associated devices and integrated circuits. This year we have 56 papers (8 invited) divided into nine sessions and more than 78 delegates from 20 countries.Fiskebäckskil is a small restful community situated by Gullmarsfjorden opposite to the village Lysekil. Gullmarsfjorden is Sweden's only true threshold fjord, 25 km deep and 1 to 3 km broad. In the 19th century the small fishing village was transformed into a shipping society. The special wood based architecture of this time is well preserved until today. During the 20th century Fiskebäckskil, surrounded by red granite and the salty sea became a prime choice for summer recreation and swimming. The conference hotel (Gullmarsstrand) building is reverentially renovated and modernised to fulfil the highest expectations for a successful workshop.The workshop is sponsored by the Swedish Research Council (VR), the IEEE Sweden Section, the Swedish Foundation for Strategic Research (SSF-HSEP), Swedish Governmental Agency for Innovation Systems (VINNOVA), OXFORD Plasma Technology and Agilent technologies. We would like to thank these organisations for their support. We would also like to thank everyone who helped to arrange WOCSDICE 2006: the international steering committee for advice; the local organising committee; Eva Hellberg and Peter Jönsson for all WEB support; Catharina Forssén, and Ingrid Collin for help with registrations and payments; the session chairs; and everyone who attends or contributes with a presentation.On behalf of the local organisation committee, we would like to welcome all of you and wish you a pleasant and fruitful stay in Fiskebäckskil.Welcome!Jan Stake and Jan GrahnWOCSDICE2006 Chairmen
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| 24. |
- Ahlberg Gagnér, Viktor, 1989, et al.
(författare)
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Clustering of atomic displacement parameters in bovine trypsin reveals a distributed lattice of atoms with shared chemical properties
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Low-frequency vibrations are crucial for protein structure and function, but only a few experimental techniques can shine light on them. The main challenge when addressing protein dynamics in the terahertz domain is the ubiquitous water that exhibit strong absorption. In this paper, we observe the protein atoms directly using X-ray crystallography in bovine trypsin at 100 K while irradiating the crystals with 0.5 THz radiation alternating on and off states. We observed that the anisotropy of atomic displacements increased upon terahertz irradiation. Atomic displacement similarities developed between chemically related atoms and between atoms of the catalytic machinery. This pattern likely arises from delocalized polar vibrational modes rather than delocalized elastic deformations or rigid-body displacements. The displacement correlation between these atoms were detected by a hierarchical clustering method, which can assist the analysis of other ultra-high resolution crystal structures. These experimental and analytical tools provide a detailed description of protein dynamics to complement the structural information from static diffraction experiments. © 2019, The Author(s).
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| 25. |
- Alderman, Byron, et al.
(författare)
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A New Pillar Geometry for Heterostructure Barrier Varactor Diodes
- 2001
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Ingår i: 12th International Symposium on Space Terahertz Technology. ; , s. 330-339
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Konferensbidrag (refereegranskat)abstract
- We report on a novel diode geometry, with reduced thermal resistance, for Heterostructure Barrier Varactor, HBV, diodes. The pillar geometry presented here involves the complete removal of the substrate, electrical contacted is made by the forward and reverse side processing of metallic pillars. We propose that there is a limit to the maximum number of barriers that can be used to increase the power capability of a HBV. An analytical model has been developed to study these effects. In considering the case of a perfect thermal heat sink the limit is found to be fourteen, in applying this model to the new pillar structure this is reduced to six.
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