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| 2. |
- Dochev, Dimitar, 1981-, et al.
(författare)
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A Technology Demonstrator for 1.6–2.0 THz Waveguide HEB Receiver with a Novel Mixer Layout
- 2011
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Ingår i: Journal of Infrared, Millimeter and Terahertz Waves. - 1866-6892. ; 32:4, s. 451-465
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present our studies on a technology demonstrator for a balanced waveguide hot-electron bolometer (HEB) mixer operating in the 1.6–2.0 THz band. The design employs a novel layout for the HEB mixer combining several key technologies: all-metal THz waveguide micromachining, ultra-thin NbN film deposition and a micromachining of a silicon-on-insulator (SOI) substrate to manufacture the HEB mixer. In this paper, we present a novel mixer layout that greatly facilitates handling and mounting of the mixer chip via self-aligning as well as provides easy electrical interfacing. In our opinion, this opens up a real prospective for building multi-pixel waveguide THz receivers. Such receivers could be of interest for SOFIA, possible follow up of the Herschel HIFI, and even for ground based telescopes yet over limited periods of time with extremely dry weather (PWV less than 0.1 mm).
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| 3. |
- Billade, Bhushan, 1982-, et al.
(författare)
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Performance of the first ALMA Band 5 production cartridge
- 2011
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Ingår i: Proceedings of the 22nd International Symposium on Space Terahertz Technology, April 26-28th, 2011 - Tucson, Arizona, USA. ; s. -2
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Konferensbidrag (refereegranskat)abstract
- We present performance of the first ALMA Band 5 production cartridge, covering RF frequencies from 163 GHz to 211 GHz. ALMA Band 5 is a dual polarization, sideband separation (2SB) receiver based on all Niobium (Nb) SuperconductorInsulator-Superconductor (SIS) tunnel junction mixer, providing 16 GHz of instantaneous RF bandwidth for the astronomy observations. The 2SB mixer for each polarization employs a quadrature layout. The sideband separation occurs at the output of the IF hybrid that has integrated bias-T for biasing the mixers, and is produced using superconducting thin film technology. Experimental verification of the Band 5 cold cartridge performed together with warm cartridge assembly, confirms the system noise temperature below 45 K, less than five quantum noise (5 hf/k) over most of the RF band, which is to our knowledge, the best results at these frequencies. The measurement of the sideband rejection indicates that the sideband rejection better than 10 dB over 90% of the observational band.
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| 4. |
- Belitsky, Victor, 1955-, et al.
(författare)
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Towards Multi-Pixel Heterodyne Terahertz Receivers
- 2011
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Ingår i: Proceedings of the 22nd International Symposium on Space Terahertz Technology, Tucson, AZ, USA, April 26-28, 2011. ; s. 1-3
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Konferensbidrag (refereegranskat)abstract
- Terahertz multi-pixel heterodyne receivers introduce multiple challenges for their implementation, mostly due to the extremely small dimensions of all components and even smaller tolerances in terms of alignment, linear dimensions and waveguide component surface quality. In this manuscript, we present a concept of terahertz multi-pixel heterodyne receiver employing optical layout using polarization split between the LO and RF. The frontend is based on a waveguide balanced HEB mixer for the frequency band 1.6 – 2.0 THz. The balanced HEB mixer follows the layout of earlier demonstrated APEX T2 mixer. However for the mixer presented here, we implemented splitblock layout offering minimized lengths of all waveguides and thus reducing the associated RF loss. The micromachining methods employed for producing the mixer housing and the HEB mixer chip are very suitable for producing multiple structures and hence are in-line with requirements of multi-pixel receiver technology. The demonstrated relatively simple mounting of the mixer chip with self-aligning should greatly facilitate the integration of such multi-channel receiver.
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| 5. |
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Chalmers Environmental Initiative Progress Report 2001
- 2001
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Samlingsverk (redaktörskap) (övrigt vetenskapligt)abstract
- The Board of the Chalmers University of Technology Foundation decided in 1999 to invest SEK 100 million in a strategic investment in the environment with a special focus on environmental systems analysis. This investment was entitled The Chalmers Environmental Initiative (CEI). Through this environmental initiative Chalmers has acquired a prominent international position within environmental systems analysis. CEI is the result of the active research and education that has taken place at Chalmers over the past 10 years. A broad base in combination with leading edge technology presented the opportunity to create a very strong research programme based on interaction between the various schools at Chalmers. As CEI is integrated into undergraduate and doctoral programmes at Chalmers, engineers, architects and doctoral students have access, within the framework of their studies, to research-based environmental education with a focus on a sustainable society. CEI also co-operates with other parties, such as industry, politicians, various organisations and the general public, as a further means of contributing to sustainable development in society. Within CEI, seven new professors have been appointed within the following areas: Management for Sustainability Rolf Wolff, 1 June 2000 Environmental Systems Technology Anne-Marie Tillman, 1 September 2000 Sustainable Industrial Metabolism Christian Azar, 1 September 2000 Global Environmental Measurements Donal Murtagh, 1 November 2000 Green Chemistry William J. Frederick Jr, 1 August 2001 Sustainable Energy Systems Filip Johnsson, preliminary 1 October 2001 Design for Sustainable Urban Development Vacant: interviews during April 2001 The four professors appointed in 2000 are presented in this report as well as their declaration of intent for the next few years. At present, the CEI professors are involved with approximately 40 universities, institutes and industrial partners in the form of project co-operation and joint publications. The four professors have the greater proportion of their environmental research funded through external grants, compared to CEI. The proportion of faculty funds and other internal Chalmers funds is at present very low. A summary of the financing structure is also included in this report. During 2001, various forms of co-operation were initiated between the professors, such as joint project plans, doctoral students, courses and graduate schools. During autumn 2001, a residential seminar is planned for discussions within CEI as well as an open presentation of the project and the professors. This major in-house focus on environmental research has attracted attention externally and contributed to the opening up of new potential in combination with increased expectations. Since May 1, 2000, Chalmers has been a member of the Alliance for Global Sustainability (AGS), an association of some of the world’s foremost universities in the environmental field. AGS and other platforms form the basis for international research collaboration. CEI and other environmental activities have led to spin-off effects and contributed to increased interest in Chalmers as an environmental university. Chalmers and Göteborg University were, for example, jointly awarded the King Carl XVI Gustaf visiting professorship in environmental science for 2001-2002 and Margot Wallström received an honorary doctorate from Chalmers in 2001. A large number of well-known environmental researchers have also visited Chalmers to take part in conferences and seminars, including the winners of the Volvo Environmental Award for 2000 and the winner of the City of Göteborg International Environmental Award for 2000.
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| 6. |
- Desmaris, Vincent, 1977-, et al.
(författare)
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All-metal micromachining for the fabrication of sub-millimetre and THz waveguide components and circuits
- 2008
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Ingår i: Journal of Micromechanics and Microengineering. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- A novel technology for the manufacturing of micromachined all-metal waveguide circuits and structures for frequency bands ranging from 200 up to 7000 GHz (sub-millimetre and THz) is presented. The waveguide circuits are formed by using metal electroplating with preceding sputtering of a thin metal film seed layer over a photo-lithographically patterned thick SU-8 photoresist. The process provides the possibility of making three-dimensional structures via facilitating multi-level (layered) designs. The surface roughness of the THz waveguide structure was demonstrated to be as low as 30 nm. This technology was used to build a state-of-the-art waveguide balanced 1.3 THz hot electron bolometer mixer and other applications for radio astronomy instrumentation.
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| 7. |
- Desmaris, Vincent, 1977-, et al.
(författare)
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Microfabrication Technology for All-Metal Sub-mm and THz Waveguide Receiver Components
- 2008
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Ingår i: In Proceedings of The 19th International Symposium on Space Terahertz Technology, Groningen, 28-30 April, 2008, ed. W. Wild, Space Research Organization of the Netherlands (SRON). ; part I, s. 342-345
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Konferensbidrag (refereegranskat)abstract
- A novel technology for manufacturing of micromachined all-metal waveguide circuits and structures for the frequency band from 200 up to 7000 GHz (Sub-Millimeter and THz) is presented. The waveguide circuits are formed using metal electroplating with preceding sputtering of a thin metal film seed layer over a photo-lithographically patterned thick SU-8 photo-resist. The process provides possibility of making 3-dimensional structures via facilitating of multi-level (layered) designs. Surface roughness of the THz waveguide structure was demonstrated to be below 0.1 µm. This technology was used to build a state-of-the art waveguide balanced 1.3 THz Hot Electron Bolometer mixer and other application for radio astronomy instrumentation.
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| 8. |
- Lööf, Johan, 1979-, et al.
(författare)
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Optimizing Locator Position to Maximize Robustness in Critical Product Dimensions
- 2010
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Ingår i: Proceedings of the ASME 2009 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, IDETC/CIE 2009, August 30 - September 2, 2009, San Diego, California, USA. - 978-0-7918-4899-9 ; s. 515-522
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Konferensbidrag (refereegranskat)abstract
- The way parts are located in relation to each other or in fixtures is critical for how geometrical variation will propagate and cause variation in critical product dimensions. Therefore, more emphasis should be put on this activity in early design phases in order to avoid assembly and production problems later on. In earlier literature, locator positions have been defined using optimization to reach a robust locating scheme. This implies that the total robustness of a part is optimized by placing the locators in an optimal way. Sometimes there are areas on parts that are more sensitive to variation than others. Therefore, this paper suggests an approach for optimizing the positions of locators in a locating scheme to maximize robustness in defined critical dimensions. A formulation of an optimization problem is presented, and an algorithm solving this in a heuristic approach is developed. Finally, this algorithm is applied on an industrial example.
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| 9. |
- Monje, Raquel, 1979-, et al.
(författare)
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A 0.5 THz Sideband Separation SIS Mixer for APEX Telescope
- 2008
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Ingår i: In Proceedings of The 19th International Symposium on Space Terahertz Technology, Groningen, 28-30 April, 2008, ed. W. Wild, Space Research Organization of the Netherlands (SRON). ; Part II, s. 439-443
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Konferensbidrag (refereegranskat)abstract
- We present the design and the experimental results of a fixed-tuned sideband-separating superconductor-insulator-superconductor (SIS) mixer for 385 - 500 GHz. The sideband separation is achieved using a quadrature scheme, where two separate DSB mixer blocks are combined with an intermediate waveguide component containing the LO waveguide distribution circuitry and RF waveguide hybrid. The intermediate waveguide piece is fabricated by using copper micromachining, which gives dimensions’ accuracy better than 1 μm. The RF signal coming from the waveguide hybrid is coupled to the SIS junctions through an E-probe with integrated bias-T. We implemented an on-chip LO injection solution, where the LO coupler is integrated onto the mixer chip and fabricated together with the SIS junction and the tuning circuitry. The on-chip LO coupler is made as a combination of superconducting microstrip lines and slot-lines (branches), which gives almost a lossless solution. With the fabrication accuracy better than 0.5 μm by using optical lithography, the circuitry is proven to give a good performance following the simulations expectations.
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| 10. |
- Kerzenmacher, T., et al.
(författare)
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Validation of NO2 and NO from the Atmospheric Chemistry Experiment (ACE)
- 2008
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Ingår i: Atmospheric Chemistry and Physics. - 1680-7316. ; 8:19, s. 5801
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Tidskriftsartikel (refereegranskat)abstract
- Vertical profiles of NO2 and NO have been obtained from solar occultation measurements by the Atmospheric Chemistry Experiment (ACE), using an infrared Fourier Transform Spectrometer (ACE-FTS) and (for NO2) an ultraviolet-visible-near-infrared spectrometer, MAESTRO (Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation). In this paper, the quality of the ACE-FTS version 2.2 NO2 and NO and the MAESTRO version 1.2 NO2 data are assessed using other solar occultation measurements (HALOE, SAGE II, SAGE III, POAM III, SCIAMACHY), stellar occultation measurements (GOMOS), limb measurements (MIPAS, OSIRIS), nadir measurements (SCIAMACHY), balloon-borne measurements (SPIRALE, SAOZ) and ground-based measurements (UV-VIS, FTIR). Time differences between the comparison measurements were reduced using either a tight coincidence criterion, or where possible, chemical box models. ACE-FTS NO2 and NO and the MAESTRO NO2 are generally consistent with the correlative data. The ACE-FTS and MAESTRO NO2 volume mixing ratio (VMR) profiles agree with the profiles from other satellite data sets to within about 20% between 25 and 40 km, with the exception of MIPAS ESA (for ACE-FTS) and SAGE II (for ACE-FTS (sunrise) and MAESTRO) and suggest a negative bias between 23 and 40 km of about 10%. MAESTRO reports larger VMR values than the ACE-FTS. In comparisons with HALOE, ACE-FTS NO VMRs typically (on average) agree to ±8% from 22 to 64 km and to +10% from 93 to 105 km, with maxima of 21% and 36%, respectively. Partial column comparisons for NO2 show that there is quite good agreement between the ACE instruments and the FTIRs, with a mean difference of +7.3% for ACE-FTS and +12.8% for MAESTRO.
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