| 1. |
- Belitsky, Victor, 1955, et al.
(författare)
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Facility Heterodyne Receiver for the Atacama Pathfinder Experiment Telescope
- 2007
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Ingår i: Proceedings of Joint 32nd International Conference on Infrared Millimeter Waves and 15th International conference on Terahertz Electronics, Sept 3-7, 2007, City Hall, Cardiff, Wales, UK. ; , s. 326-328
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Konferensbidrag (refereegranskat)
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| 2. |
- Belitsky, Victor, 1955, et al.
(författare)
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Terahertz Instrumentation For Radio Astronomy
- 2009
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Ingår i: International Symposium on Terahertz Science and Technology between Japan and Sweden. ; , s. 28-29
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Radio Astronomy was always a frontrunner in the demand on terahertz technology. Millimetre and sub-millimetre wave receivers operate at ground-based observatories for more than 20 years with real Terahertz instruments making its way to ground-based [1] and space-based observatories, e.g., Herschel HIFI, during last years.In this talk, we will look at the key requirements to the radio astronomy and environmental science terahertz receivers using heterodyne technology. The most promising and established technologies for high-resolution spectroscopy instrumentation will be discussed. Using results of the Group for Advanced Receiver Development for Onsala Space Observatory 20 m telescope, for Atacama Pathfinder Experiment (APEX) telescope and ALMA Project Band 5, we will illustrate the trends and achievements in the terahertz instrumentation for radio astronomy.
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| 3. |
- Lapkin, Igor, 1963, et al.
(författare)
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Optics Design and Verification for the APEX Swedish Heterodyne Facility Instrument (SHeFI)
- 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. 351-357
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Konferensbidrag (refereegranskat)abstract
- We present the design and verification of the receiver optics for the Single-Pixel HeterodyneFacility Instrument (SHFI) of the APEX telescope [1]. The SHFI is designed to cover thefrequency band 211 – 1390 GHz in 6 receiver channels. Four of the receiver channels have beendesigned, installed and characterized: 211-275 GHz (Band 1); 275-370 GHz (Band 2); 385-500 GHz (Band 3); 1250-1390 GHz (Band T2). The first three bands employ 2SB SIS mixertechnology and Band T2 employs HEB mixers in a waveguide balanced mixer configuration.The entire optics design was driven by the receiver position in the telescope Nasmyth cabin“A” (Fig.1) and the aperture limit of Ø150 mm, introduced by the elevation encoder inside theNasmyth tube A. This layout and the telescope geometry (~ 6 m distance from the focal plane tothe Cabin A) lead us to choose a single-pixel configuration and required using intermediateoptics with long focal distances. The common optics path, coupling the receivers to theCassegrain sub-reflector, consists of the three offset ellipsoidal mirrors, M3, M6, M8s, and threeflat mirrors, F4, F5, and F7s. The combination M3 and M6 via flat F4, F5, creates a Gaussiantelescope, providing frequency-independent re-imaging of the antenna focal plane from theCassegrain cabin into the Nasmyth cabin A. Switching between channels is achieved by theprecision rotating of the active mirror M8s. The mirror M8s in combination with each channelactive mirror M10 provides re-imaging of the secondary onto the feed horn aperture of theselected channel. Such a configuration provides frequency independent illumination of thesecondary with the edge taper -12dB. The angular position of the flat mirrors F9 is adjustable andgives additional possibility of fine-tuning of the beam alignment from the common optics toevery receiver channels.Verification of the optical designthrough measurements is essential inorder to align the beams from thecryostat windows to the commonoptics to minimize loss in thequasioptical guiding system. In orderto verify the design of the cold optics(corrugated horn + M10) in terms ofGaussian beam parameters, a newwideband vector field measurementsystem was developed [2]. Vectorfield measurements were performedfor band 1, 2, and 3, and scalarmeasurements were employed for theTHz band.
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| 4. |
- Nyström, Olle, 1979, et al.
(författare)
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Optics Design and Verificatgion for the APEX Swedish Heterodyne Facility Instrument (SHeFI)
- 2009
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Ingår i: Journal of Infrared, Millimeter, and Terahertz Waves. - : Springer Science and Business Media LLC. - 1866-6892 .- 1866-6906. ; 30:7, s. 746-761
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present the design and verification of the optics of the Swedish Heterodyne Facility Instrument (SHeFI) receiver installed in the Atacama Pathfinder EXperiment (APEX) telescope during spring 2008. SHeFI is located in the Nasmyth instrumentation Cabin A (NCA). The receiver has been designed to have 6 frequency channels, of which four receiver channels have been built, and characterized: 211-275 GHz(Band 1), 275-370 GHz (Band 2), 385-500 GHz (Band 3), and 1250-1390 GHz (Band T2). Bands 1, 2, and T2 are installed at the telescope and are currently in operation. The optical design is driven by the requirement of frequency independent illumination of the secondary with -12 dB edge taper for each frequency channel and the limitation (beam clearance through the Nasmyth tube and the elevation encoder) imposed by the receiver position in the NCA. This paper describes the design approach, optimization, and verification of the optical system, coupling each individual receiving beam to the common optics of the telescope.
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| 5. |
- Vassilev, Vessen, 1969, et al.
(författare)
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A Swedish heterodyne facility instrument for the APEX telescope
- 2008
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 490:3, s. 1157-1163
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Tidskriftsartikel (refereegranskat)abstract
- In March 2008, the APEX facility instrument was installed on the telescope at the site of Lliano Chajnantor in northern Chile. The main objective of the paper is to introduce the new instrument to the radio astronomical community. It describes the hardware configuration and presents some initial results from the on-sky commissioning.The heterodyne instrument covers frequencies between 211 GHz and 1390 GHz divided into four bands. The first threebands are sideband-separating mixers operating in a single sideband mode and based on superconductor-insulator-superconductor (SIS) tunnel junctions. The fourth band is a hot-electron bolometer, waveguide balanced mixer. All bands are integrated in a closedcycle temperature-stabilized cryostat and are cooled to 4 K.We present results from noise temperature, sideband separation ratios, beam, and stability measurements performed on the telescope as a part of the receiver technical commissioning. Examples of broad extragalactic lines are also included.
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| 6. |
- Nyström, Olle, 1979, et al.
(författare)
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Low-Noise Cryogenic Amplifier built using Hybrid MMIC-like / TRL Technique
- 2008
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Ingår i: GigaHertz Symposium, March 5-6, 2008, Göteborg.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- HEMT cryogenic low-noise amplifiers are an important part of instrumentation: the amplifiersuse as a front-end for different measurements and as IF amplifiers in heterodyne receivers.During last few years the low-noise limit has reached as low level as approximately 0.5 K/GHzfor GaAs [1] and 0.25 K/GHz for InP HEMT [2]. However, besides electrical performanceimprovement there were not many improvements on mass and dimension side of suchamplifiers as they were built based on standard TRL technology with discrete active andpassive components. Mass and dimensions are also very important for real applications. Whenultimate low-noise performance is placed in focus, pure MMIC technology seems to looseagainst design using discrete components. With this in view, pioneered work by E. F. Lauria,et. al. [3] have successfully demonstrated a design employing MMIC approach while usingdiscrete components and based on a microstrip on Cuflon with lumped bias network.Encouraged by this work, we propose a compact design of a 4-8 GHz cryogenic low noiseamplifier using a combination of standard TRL and lumped element technology to achieveboth ultimate noise performance over the specified band and a very compact size. In ourdesign, the size reduction of the amplifier is realized by selecting an alumina substrate with ahigh dielectric constant, (εr = 9.9), but also by taking advantage of the lumped networks in thematching and bias circuitries. Avoiding quarter wave transformers and instead use a lumpedelement design approach opens up for the possibilities to reach greater bandwidths andsimultaneously obtain a more compact design. In order to make optimum design, we haveperformed extensive simulations. Each amplifier stage has been simulated in Agilent EMDS,3D electromagnetic field simulation package, including the single layer capacitors, and thenimplemented in the ADS circuit simulations as an S-parameter file. Over the 4-8 GHz band, thesimulations predict noise temperature, Taverage 35 dB. The transistors selected for the design are commercial InP HEMT (HRL) chosendue to their excellent noise performance [2], but also for the very low power consumption,which is of great importance at cryogenic temperatures. All the components used in the RFsignalpath and in the bias circuits are mounted with conductive epoxy. Apart from the RFsignalpath, all components are interconnected via bond-wires. Fine tuning is done by adjustingthe length and loop heights of the bond-wires. At the conference we plan to report results ofmeasurement and characterization of the prototype amplifier.REFERENCES:[1] C Risacher, et. al., “Low Noise and Low Power Consumption Cryogenic Amplifiers forOnsala and Apex Telescopes”, Proceedings of Gaas 2004, October 2004, Amsterdam.[2] N. Wadefalk, et. al., “Cryogenic Wide-Band Ultra-Low Noise IF Amplifier Operating atUltra-Low DC-Power”, IEEE Transactions on Microwave Theory and Techniques, vol. MTT-51, no. 6 June 2003.[3] E. F. Lauria, et. al., “A 200-300 GHz SIS Mixer-Preamplifier with 8 GHz IF Bandwidth”,2001 IEEE International Microwave Symposium, Phoenix, AZ, May 2001.
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| 7. |
- Vassilev, Vessen, 1969, et al.
(författare)
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Design and Characterization of a 211-275 GHz Sideband Separating Mixer for the APEX Telescope
- 2008
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Ingår i: IEEE Microwave and Wireless Components Letters. - 1558-1764 .- 1531-1309. ; 18:1, s. 58 - 60
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Tidskriftsartikel (refereegranskat)abstract
- We present the final results of the development and characterization of the sideband separating superconductor-insulator-superconductor (SIS) mixer for the APEX telescope band 1 (211-275 GHz).The sideband separation is achieved by using a quadrature scheme where the RF and a local oscillator (LO) power are applied to two identical double sideband SIS mixers. All mixer components, including the LO and RF distribution circuitry, are integrated into a single mixer block. To achieve a compact design we developed a superconducting Lange coupler, based on Nb thin film, which is used as an IF hybrid. Typical single sideband noise temperature of 100˚K and sideband rejection ratio of about 12 dB and are measured.
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| 8. |
- Gradinarsky, Lubomir, 1970, et al.
(författare)
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A method for detection of powder materials in metallic hollow structures using microwaves
- 2008
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Ingår i: Measurement: Journal of the International Measurement Confederation. - : Elsevier BV. - 0263-2241. ; 41:6, s. 637-646
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a method for detection of the presence of small amounts of solids (powders, granules, etc.) inside metallic structures such as process vessels and containers. The method is based on propagation of microwave electromagnetic (EM) energy inside the structures and analysing the complex reflection coefficient Gamma represented by the scattering parameter S-11. 3D EM simulations were used to predict the behaviour of S for structures of rectangular, circular, and conical shapes, contaminated with materials with weak dielectric properties. The suggested method sensitivity and the effects of the material size and its distribution were assessed and results presented of comparisons of simulations and measurements. This paper demonstrates the ability to detect very low levels of contamination, e.g. of the order of 0.01-0.03 parts of a reference vessel's volume of one (e.g. length = 1 cm, width = 0.5 cm, and height = 2 cm) for materials with weak dielectric properties. This sensitivity is even better in terms of volume ratio (contamination/vessel's volume) for structures with bigger volumes and contaminants with stronger dielectric properties e.g. wet powders. The method is fully scalable for vessels with different sizes. Therefore industrial application of the method to physical processing of pharmaceutics, food, agriculture and others is envisioned. (C) 2007 Elsevier Ltd. All rights reserved.
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| 9. |
- Nyström, Olle, 1979, et al.
(författare)
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A Vector Beam Measurement System for 211-275 GHz
- 2006
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Ingår i: Proceedings 17th International Symposium on Space Terahertz Technology, Paris, FRANCE.. ; , s. P2-28
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Konferensbidrag (refereegranskat)abstract
- We propose a novel design for a vector measurement system for the characterization of mm-wave receiver optics alignment across the 211-275 GHz band. Previous published work on vector mm and submm beam measurements employs phase-locked loops (PLLs) with Gunn-oscillators and/or multiple frequency sources, [1], [2]. We are developing a measurement set-up without any PLLs and employ the combination of a single frequency source, comb-generator and direct multiplication LO unit. The design takes advantage of different harmonics used to generate the RF and LO signals and to create the desired IF. Importantly, at the same time it allows obtaining a perfect phase-coherence and initial phase-noise cancellation.The signal source is a vector network analyzer (VNA). In the suggested scheme the VNA generates a signal, fsource, which is fed into a comb-generator that generates number of frequencies ∆fsource apart. When fsource is low, this results in a large number of closely spaced, phase-coherent frequencies. Since any selection among the generated frequencies is phase-coherent, any two of them can be used to produce phase-coherent RF and LO signals by filtering and multiplication. As a test source we use a harmonic mixer mounted on a xyz-scanner. Its absolute position with respect to the receiver optics is predefined by means of triangulation system comprising lasers and position sensitive detectors. The IF from the SIS mixer is down-converted using suitable reference from the comb generator to produce an IF equal to fsource. This signal is fed into Port 2 of the VNA and amplitude and phase are measured. The advantage of using comb generator is to have closely spaced frequencies to choose from and therefore ease the production of the desired IF-frequency and obtaining initial-phase-noise cancellation. Most of the phase-noise is cancelled in the down-conversion in the SIS-mixer and the remaining is cancelled in the second down-conversion before the measurements in the VNA. The cancellation of the remaining phase-noise present at IF is obtained by selecting also the LO, for the second down-conversion, from the harmonics generated by the comb-generator.We also propose to use the same measurement set-up for the frequency bands 275-370 GHz and 385-500 GHz. We believe that our system design has the potential to cover all three bands by only replacing two filters and the LO multiplication unit. Scalar beam measurements up to 320 GHz have already demonstrated a dynamic range of about 20 dB with the harmonic mixer as the RF transmitting source [3]. We expect that vector measurements provide even greater dynamic range, indicating that we can push the frequency even higher with this harmonic mixer as the RF comb source. At the moment we are in the assembly phase of the system design and intend to present results from measurements of the Band 1 of the Facility receiver for Atacama Pathfinder EXperiment (APEX) at the time for the Conference.
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| 10. |
- Nyström, Olle, 1979, et al.
(författare)
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A Vector Beam Measurement System for 211-275 GHz
- 2006
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Ingår i: Proceedings EuCAP 2006, Nice, France, 6-10 November 2006, (ESA SP-626, October 2006). - 9290929375
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Konferensbidrag (refereegranskat)abstract
- In this paper, we describe a novel vector measurement system for the characterization of Gaussian beams and present test results for mm-wave, 211-275 GHz, receiver optics alignment. The measurement setup allows a simpler design without any PLLs and employs a combination of a single frequency source, comb-generator, and direct multiplication LO and signal sources. The system takes advantage of different harmonics to generate the required RF and LO signals yielding the desired IF frequency while obtaining perfect phase-coherence and initial phase-noise cancellation. One of the additional advantages of the suggested measuring scheme is that it allows such design that it has the potential to cover different mm and sub-mm bands by only replacing two filters and the LO multiplication unit. For example, we plan to use the same setup, with mentioned modifications, for the frequency bands 275-370 GHz and 385-500 GHz.
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