| 1. |
- Emrich, Christina, et al.
(författare)
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Low Power Cryogenic Rad-hard LNAs for Space
- 2019
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Konferensbidrag (refereegranskat)abstract
- We present the design and implementation of a packaged cryogenic InP HEMT MMIC LNA for space borne applications. The particular module is part of the submillimetre wave instrument (SWI) band1 and band2 receiver channel development for the ESA Jupiter ICy moons Explorer mission (JUICE) programme. The main objective of the activity has been to develop a general connectorized rad-hard LNA package for space applications, and to qualify the cryogenic InP HEMT MMIC process at Chalmers University of Tehnology which today covers a frequency range up to the W-band with state-of-the-art performance in terms of noise, gain and power dissipation. The activity has currently moved from a pre-qualification phase to a lot acceptance test (LAT) phase and has up till now included various environmental tests e.g. vibration, total dose radiation tests up to 300kRad on die level, and thermal cycling both to hot and cold temperatures. The InP HEMT MMIC process can be operated at ultra low power with ultra low noise which makes it an excellent candidate for deep space missions and satellite communication links, but also for the next generation of radioastronomy telescopes based on cryogenic receivers e.g. HEB and SIS multipixel cameras.
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| 2. |
- Nyström, Olle, 1979, et al.
(författare)
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PHOCUS Radiometer Payload
- 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. P-9
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Konferensbidrag (refereegranskat)abstract
- PHOCUS – Particles, Hydrogen and Oxygen Chemistry in the Upper Summer Mesosphere is a Swedish sounding rocket experiment with the main goal of investigating the upper atmosphere in the altitude range 50-110 km. This paper describes the radiometer instruments (SondRad) in the PHOCUS payload, which are intended to explore the water vapour concentration in connection with the appearance of noctilucent (night shining) clouds. The design of the radiometer system has been done in collaboration between Omnisys Instruments AB and the Group for Advanced Receiver Development (GARD) at Chalmers University of Technology where Omnisys was responsible for the design, implementation, and verification of the radiometers and backend and GARD was responsible for the optics and calibration systems. The radiometers cover the water absorption lines at 183 GHz and 557 GHz with 67 kHz backend resolution. The 183 GHz channel is a side-looking radiometer while the 557 GHz radiometer is placed along the rocket axis looking in the forward direction. Both channels employ sub-harmonically pumped Schottky mixers and FFT spectrometer back-ends. The 183 GHz channel employs a CW-pilot signal calibrating the entire receiving chain while the IF-chain of the 557 GHz channel is calibrated by injecting a signal from a calibrated noise source through a directional coupler. The instrument will collect complete spectra for both the 183 and 557 GHz with 300 Hz rate for the 183 GHz channel and 10 Hz for the 557 GHz channel for about 60 seconds reaching the apogee of the flight trajectory and 100 seconds after that. With lossless data compression using variable resolution over the spectrum, the data set is reduced to 2 x 12 MByte.
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| 3. |
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| 4. |
- 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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| 5. |
- 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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| 6. |
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| 7. |
- Anderberg, Martin, 1992, et al.
(författare)
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A 183-GHz Schottky diode receiver with 4 dB noise figure
- 2019
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - : IEEE. - 0149-645X. ; 2019-June, s. 172-175
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Konferensbidrag (refereegranskat)abstract
- Atmospheric science based on space-borne millimeter wave measurements require reliable and state-of-the art receivers. In particular, the water vapor line at 183.3 GHz motivates the development of sensitive mixers at this frequency. Traditional assembly techniques employed in the production of Schottky diode receivers involve flip-chip mounting and soldering of discrete dies, which prohibit the implementation of reliable and repeatable production processes. In this work, we present a subharmonic 183 GHz mixer implementing a repeatable assembly method using beamlead Schottky diodes. The mixer was integrated with a InP HEMT MMIC low noise intermediate frequency amplifier resulting in a record-low receiver noise temperature of 450 K at 1 mW of local oscillator power measured at room-temperature. The measured Allan time was 10 s and the third order local oscillator spurious power was less than -60 dBm. The proposed assembly method is of particular importance for space-borne missions but also applicable to a wide range of terahertz applications.
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| 8. |
- Auriacombe, Olivier, 1989, et al.
(författare)
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325 GHz and 650 GHz Dual-polarisation receivers Concept
- 2022
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Ingår i: 32nd International Symposium of Space Terahertz Technology, ISSTT 2022.
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Konferensbidrag (refereegranskat)abstract
- The integrated dual-polarisation receivers utilize a dual probe concept, efficiently integrating the antenna and MMIC package environment which allows for polarisation discrimination without the use of bulky and lossy external orthomode transducers. This concept increases the sensitivity of the instrument and reduces its size, enabling the development of future earth observation arrays. Omnisys Instruments AB (Sweden) and Chalmers University of Technology (Sweden) are working to demonstrate state-of-the-art dual polarisation capability with two integrated receiver modules at 325 GHz and 650 GHz.
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| 9. |
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| 10. |
- Emrich, Anders, 1962, et al.
(författare)
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Water Vapor Radiometer for ALMA
- 2009
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Ingår i: Proc. of 20th International Symposium on Space Terahertz Technology, Charlottesville, USA, 20-22 April, 2009. ; , s. 174-177
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Konferensbidrag (refereegranskat)abstract
- Radiometer for the ALMA project from scratch in 18 months and will deliver 50 units within the next 18 months. Theradiometer includes an Optical Relay, Mounting Frame as well as the Radiometer core module. The radiometer core include optics and calibration system as well as a schottky mixer based frontend and a filterbank back-end. These subsystems are supported by a thermal management subsystem, control and communication subsystem as well as a power subsystem. The system and subsystems will be described in the paper.
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| 11. |
- Emrich, Anders, 1962, et al.
(författare)
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Wideband Receivers for VLBI2010 Applications
- 2013
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Ingår i: Progress in Electromagnetics Research Symposium, PIERS 2013, Stockholm, Sweden, August 12-15, 2013.
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Konferensbidrag (refereegranskat)
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| 12. |
- Gunnarsson, Sten, 1976, et al.
(författare)
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A Single-Chip 53 GHz Radiometer Front-End MMIC for Geostationary Atmospheric Measurements
- 2008
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Ingår i: 2008 IEEE Radio and Wireless Symposium, RWS; Orlando, FL; United States; 22 January 2008 through 24 January 2008. - 9781424414635 ; , s. 867-870
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Konferensbidrag (refereegranskat)abstract
- A multi-functional single-chip 53 GHz radiometer front-end MMIC has been designed in a commercial GaAs mHEMT technology and evaluated by probed measurements. To the best of the authors' knowledge, this is the first multi-functional MMIC ever presented intended for a radiometer application. Thus, the presented MMIC represents the future in radiometer front-end design, enabling a new generation of radiometers with lower cost, weight and DC power consumption. The MMIC is intended to be used in a demonstrator for a future geostationary synthetic thinned aperture radiometer for satellite-based environmental studies of the earth. Measured results for conversion gain, RF and IF bandwidths, image rejection ratio, 1-dB compression point, input referred third order intercept point (IIP3), LO saturation, and noise figure are presented and discussed. A study of the influence of benzocyclobutene (BCB) as a dielectric coating used for surface passivation on the measured RF performance is also performed. Furthermore, the very important issue of phase stability versus temperature and time was also investigated.
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| 13. |
- Hammar, Arvid, 1986, et al.
(författare)
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A 340 GHz High Gaussicity Smooth Spline Horn Antenna for the STEAMR Instrument
- 2014
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Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781479935383 ; , s. 649-650
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Konferensbidrag (refereegranskat)abstract
- We present the design, fabrication and measure-ments of a smooth walled spline feed horn antenna for the satellite borne climate research instrument STEAMR operating at 340GHz. A method has been developed which, for a certain desired beam waist, can be used to optimize the horn profile for high Gaussicity and ultra-low sidelobes. The simulated performance of the horn achieves a beam waist of 1.9 mm over the band 323-357 GHz with Gaussian coupling efficiency exceeding 98%. The peak cross-polar sidelobes are below -28 dB over the required frequency band. For cost effective manufacturing with high repeatability, the smooth wall spline profile is drilled in out from a metal block using a custom made broach. To validate the design and fabrication, planar measurements of the phase and amplitude have been performed and from measured E-field vital horn parameters have been extracted.
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| 14. |
- Hammar, Arvid, 1986, et al.
(författare)
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A 600 GHz Orthomode Transducer based on a Waveguide Integrated Wire Grid Polarizer
- 2012
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Ingår i: TWENTY-THIRD INTERNATIONAL SYMPOSIUM ON SPACE TERAHERTZ TECHNOLOGY (ISSTT2012).
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Konferensbidrag (refereegranskat)abstract
- Abstract — We present a new type of orthomode transducer (OMT), involving the integration of a quasi-optical component, namely a wire grid polarizer (WGP), with an E-plane probe transition, in a waveguide topology. The goal has been to create a lightweight and compact device for waveguide integration, capable of covering all frequency channels to be used by the FIRE instrument¤.The design consists of a metallic split block, in which a quadratic waveguide supporting the two fundamental modes of propagation (TE10 and TE01), is formed using regular CNC milling. Just as its quasi-optical counterpart, i.e. a free standing WGP, a waveguide integrated WGP insert is used to separate the two orthogonal TE modes, which are either reflected or transmitted (depending on polarization). A planar E-plane waveguide probe transition realized on a GaAs membrane is used inside a square waveguide to extract the reflected mode without affecting the transmitted mode. For a first proof of concept the OMT has been designed for the possibility of full characterization and therefore the transmitted mode is guided through a stepped impedance transformer to a standard rectangular waveguide interface, while a second E-plane probe transition to a rectangular waveguide, is used for the reflected mode. Simulations carried out using Ansoft HFSS show that the OMT design can be made relatively broadband (currently about ~14% with a return loss better than 15 dBs) and with cross-polarizations better than 30 dB. The probe and WGP can be manufactured using high precision photolithography or E-beam lithography making it scalable to both lower and higher frequency bands. Assembling an OMT of this type involves mounting of small membrane structures (
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| 15. |
- Hammar, Arvid, 1986, et al.
(författare)
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Low noise 874 GHz receivers for the international submillimetre airborne radiometer (ISMAR)
- 2018
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 89:5
-
Tidskriftsartikel (refereegranskat)abstract
- We report on the development of two 874 GHz receiver channels with orthogonal polarizations for the international submillimetre airborne radiometer. A spline horn antenna and dielectric lens, a Schottky diode mixer circuit, and an intermediate frequency (IF) low noise amplifier circuit were integrated in the same metallic split block housing. This resulted in a receiver mean double sideband (DSB) noise temperature of 3300 K (minimum 2770 K, maximum 3400 K), achieved at an operation temperature of 40 C and across a 10 GHz wide IF band. A minimum DSB noise temperature of 2260 K at 20 C was measured without the lens. Three different dielectric lens materials were tested and compared with respect to the radiation pattern and noise temperature. All three lenses were compliant in terms of radiation pattern, but one of the materials leads to a reduction in a noise temperature of approximately 200 K compared to the others. The loss in this lens was estimated to be 0.42 dB. The local oscillator chains have a power consumption of 24W and consist of custom-designed Schottky diode quadruplers (5% power efficiency in operation, 8%-9% peak), commercial heterostructure barrier varactor (HBV) triplers, and power amplifiers that are pumped by using a common dielectric resonator oscillator at 36.43 GHz. Measurements of the radiation pattern showed a symmetric main beam lobe with full width half maximum <5 and side lobe levels below 20 dB. The return loss of a prototype of the spline horn and lens was measured using a network analyzer and frequency extenders to be 750-1100 GHz. Time-domain analysis of the reflection coefficients shows that the reflections are below 25 dB and are dominated by the external waveguide interface.
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| 16. |
- Hammar, Arvid, 1986, et al.
(författare)
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Optical Tolerance Analysis for the STEAMR Instrument
- 2013
-
Ingår i: TWENTY-FOURTH INTERNATIONAL SYMPOSIUM ON SPACE TERAHERTZ TECHNOLOGY (ISSTT2013).
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Konferensbidrag (refereegranskat)abstract
- The optics of the STEAMR instrument is a complex system involving off-axis mirrors designed to achieve precise imaging of the 14 receiver channel beams from the far field to the corresponding feed horns. An initial optical design was generated by Swedish Space Corporation, which laid the framework for the subsequent IAP design that further developed the optical system to meet the mission performance requirements. Omnisys Instruments is now the prime contractor for the complete STEAMR instrument.Although simulations of the optics presently show good results, little is known about the sensitivity to mechanical errors, i.e. surface deviations and misalignments of the reflectors. This work encompasses a tolerance analysis for the complete optics chain consisting of a 28 reflector focal plane array (FPA) and 6 reflector relay optics. With six degrees of freedom for each reflector, the scale of the required mechanical tolerancing analysis is significant. The goal of this work is therefore to identify critical locations within the optics architecture that have the largest influence on performance.Being a multi-beam instrument, the optics requirements for STEAMR can be divided into two parts: pointing and beam quality. Pointing errors were analysed using the commercial software package ZEMAX, which offers built-in routines for performing Monte-Carlo simulations specifically for tolerancing problems. Beam quality, i.e. sidelobe levels, beam efficiency and polarization plane, were analysed using physical optics routines in GRASP. Simulations in both programs have been carried out using single element perturbation and Monte-Carlo simulations on the complete optics chain.In the first iteration of the analysis, all reflector surfaces were assumed to be perfect. In later analyses, surface errors were also added. Special attention was given to the 1.6 m x 0.8 m carbon fiber main reflector, which is the most sensitive in terms of errors in shape. By running the optical analysis in parallel and in close cooperation with the mechanical design, it has been possible to assume realistic errors for the different parts of the optics. Measurements of the feed horns done by IAP show excellent agreement with simulations, where sidelobe levels around -40 dB was predicted. Therefore, the beams of all feeds have been modelled as perfect Gaussians.
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| 17. |
- Hammar, Arvid, 1986, et al.
(författare)
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Optical Tolerance Analysis of the Multi-Beam Limb Viewing Instrument STEAMR
- 2014
-
Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 4:6, s. 714-721
-
Tidskriftsartikel (refereegranskat)abstract
- We report on an optical tolerance analysis of the submillimeter atmospheric multi-beam limb sounder STEAMR. Physical optics and ray-tracing methods were used to quantify and separate errors in beam pointing and distortion due to reflector misalignment and primary reflector surface deforma-tions. Simulations were performed concurrently with the man-ufacturing of a multi-beam demonstrator of the relay optical system which shapes and images the beams to their corresponding receiver feed horns. Results from Monte-Carlo simulations show that the inserts used for reflector mounting should be positioned with an overall accuracy better than 100 µm (~1/10 wavelength). Analyses of primary reflector surface deformations show that a deviation of magnitude 100 µm can be tolerable before deployment, whereas the corresponding variations should be less than 30 µm during operation. The most sensitive optical elements in terms of misalignments are found near the focal plane. This localized sensitivity is attributed to the off-axis nature of the beams at this location. Post-assembly mechanical measurements of the reflectors in the demonstrator show that alignment better than 50 µm could be obtained.
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| 18. |
- Hammar, Arvid, 1986, et al.
(författare)
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Stray light suppression of a compact off-axis telescope for a satellite-borne instrument for atmospheric research
- 2018
-
Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 10815
-
Konferensbidrag (refereegranskat)abstract
- In this study, simulations and measurements were used to investigate stray light properties of the three-mirror off-axis telescope of a new satellite for atmospheric research called Mesospheric Airglow/Aerosol Tomography Spectroscopy (MATS). A 700 mm breadboard baffle for stray light rejection has been designed and tested. Good performance was achieved by coating the baffle’s inside with Vantablack S-VIS R , which has a hemispherical reflectance of 0.2-0.6% across the instrument’s detection band (270-776 nm). A point source transmittance (PST) down to 10−6 was measured for the full-size baffle breadboard. This is in excellent agreement with simulations performed in OpticStudio/LightTools, where scattering was modeled using empirical BRDF data. From the breadboard results, a simulation model of a flight-representative prototype model of the entire instrument was set up in OpticStudio. Strong signals just outside the field of view constitute the biggest challenge, where a PST in the order of 10-6 − 10-4 is required. Simulations suggest that the PST of the prototype limb instrument will be lower than this. Adding to these simulations, an instrument model was developed, which will be utilized by the end-users to remove unwanted features in the data stemming from the instrument itself. Besides stray light, the model also takes into account the most relevant aspects of the instrument, such as image resolution (from measured/simulated point spread functions), image sensor characteristics as well as temperature and wavelength dependencies.
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| 19. |
- Hammar, Arvid, 1986, et al.
(författare)
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THz smooth-walled spline horn antennas: Design, manufacturing and measurements
- 2016
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Ingår i: 2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016, Fajardo, Puerto Rico, 26 June - 1 July 2016. - 1947-1491. - 9781509028863 ; , s. 1341-1342
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Konferensbidrag (refereegranskat)abstract
- We describe a versatile and cost-efficient method for producing smooth-walled spline horn antennas for applications in THz radiometry. Specifically, the development of four different horns for radiometer receiver applications at frequencies 120, 183, 340 and 874 GHz is presented. General methods for efficient optimization of the spline profiles have been developed which enable the horn designs to be tailored to each application. All four designs display high Gaussicity (typically ∼98%). Manufacturing methods based on numerical milling in splitblocks, lathing and drilling have been tested and compared. Milled splitblock horns with integrated receiver circuits (Shottky mixers in this case) allow for lower losses in the receiver system at the expense of higher cross-polarization levels. The radiation pattern of three designs at 183, 340 and 874 GHz have been measured using planar and rotational scanners.
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| 20. |
- Hammar, Arvid, 1986, et al.
(författare)
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Wide-field off-axis telescope for the Mesospheric Airglow/Aerosol Tomography Spectroscopy satellite
- 2019
-
Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 58:6, s. 1393-1397
-
Tidskriftsartikel (refereegranskat)abstract
- We present the development of a compact ?/7.3 (?=35 mm) three-mirror reflective telescope for the atmospheric-research microsatellite Mesospheric Airglow/Aerosol Tomography Spectroscopy (MATS). The telescope design was driven by the end users’ need for a reflective wide-field (5.67°×0.91°) optic with high stray light rejection and six detection channels with separate image sensors, operating at wavelengths 270–772 nm. For the first time, a design method for wide-field off-axis telescopes—in which linear astigmatism is eliminated—was applied and tested in practice. Single-point diamond turning was used to produce two sets of 37–110 mm large free-form aluminum mirrors with surface figure errors and roughness values of 34–62 nm (RMS)/193–497 nm (PV) and 2.8–3.5 nm (RMS), respectively. A method that combines precise machining and geometry measurements (using a coordinate measuring machine) was employed to fabricate an aluminum structure to accurately position the mirrors without the need for manual alignment. The telescope was tested with a network of plate beamsplitters and filters, which define the spectral selection for the six detection channels. Imaging performance measurements were carried out using a reflective off-axis collimator, which projects imaging targets at infinite focus. A modulation transfer function (MTF) value of 0.45 at 20 lp/mm was measured at ∼760 nm (diffraction limit: 0.85) using a slanted edge target. By modeling the measured mirror surfaces in optical design software, a reoptimization of the mirror positions could be performed and an improved MTF of ∼0.75 at 20 lp/mm was predicted. The results demonstrate design- and building methods that can be utilized to make off-axis telescopes for a vast range of applications.
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| 21. |
- Jacob, Karl, et al.
(författare)
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Characterization of the 530-625 GHz receiver unit for the Jupiter mission JUICE/SWI
- 2015
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Ingår i: Proceedings of the 36th ESA Antenna Workshop on Antennas and RF Systems for Space Science.
-
Konferensbidrag (refereegranskat)abstract
- The Submillimetre Wave Instrument (SWI) is being developed for the Jupiter Icy moons Explorer (JUICE) missionof the European Space Agency (ESA). In this paper we give an overview of the 530 GHz to 625 GHz receiver unit of SWI and present the first noise temperature measurements covering the complete receiver bandwidth at room temperature operation. In this context we will point out the difficulties with the highly variable local oscillator power within the bandwith, which needs a careful tuning of the multiplier bias voltages in order to optimize the noise temperature and to avoid damage of the mixers. In addition we show initial results at cold temperature operation. Furthermore we will present a first stability measurement showing the temperature dependence of the receiver gain at room temperature operation.
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| 22. |
- Jacob, Karl, et al.
(författare)
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Radiometric performance of the 530 to 625 GHz receiver unit of the submillimetre wave instrument on juice
- 2019
-
Ingår i: ISSTT 2019 - 30th International Symposium on Space Terahertz Technology, Proceedings Book. ; , s. 28-31
-
Konferensbidrag (refereegranskat)abstract
- The upcoming Submillimeter Wave Instrument on the JUICE spacecraft is a passive radiometer/spectrometer instrument with two heterodyne receivers which are independently tunable in the frequency bands 530 to 625 GHz and 1080 to 1275 GHz. It will study Jupiter’s atmosphere as well as the atmospheres and surface properties of the Galilean moons. This work presents the results of first radiometric tests with a prototype of the 600 GHz receiver. In this context, the baseline ripples caused by the internal calibration target have been characterized using two conical prototypes with a linear and an exponential absorber coating profile. A significant reduction of the baseline ripple amplitude has been measured with the target having the exponential cone profile. The spectroscopic baseline has been characterized for various frequency steps when applying frequency switching as an alternative calibration mode. At some operating frequencies a very flat switching baseline has been measured for frequency throws up to 90 MHz, while at other frequencies significant spectral distortions are measured even with a step size of 22.5 MHz. The first radiometric tests of the sideband gain ratio with a passive Fourier Transform Spectroscopy method demonstrate the general applicability in the 530 to 625 GHz band.
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| 23. |
- Karandikar, Yogesh, 1982, et al.
(författare)
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A 874 GHz Mixer Block Integrated Spline Horn and Lens Antenna for the ISMAR Instrument
- 2015
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Ingår i: 9th European Conference on Antennas and Propagation, EuCAP 2015, Lisbon, Portugal, 13-17 May 2015. - 9788890701856
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present the design of a 874 GHz mixer block-integrated antenna for the ISMAR Instrument. The spline horn antenna with a dielectric lens (Teflon) is used to fulfill the requirement of an on-axis Directivity exceeding 32 dBi. The well designed spline horn offers very high Gaussian Coupling, exceeding 97%. This property of spline horn further helps to achieve very rotationally symmetric beam even after the lens with very low cross-polarization (
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| 24. |
- Neumaier, Philipp, 1984, et al.
(författare)
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Molecular Spectroscopy With a Compact 557-GHz Heterodyne Receiver
- 2014
-
Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 4:4, s. 469-478
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a heterodyne terahertz spectrometer based on a fully integrated 557-GHz receiver and a digital fast Fourier transform spectrometer. The receiver consists of a chain of multipliers and power amplifiers, followed by a heterostructure barrier varactor tripler that subharmonically pumps a membrane GaAs Schottky diode mixer. All sub-components are newly developed and optimized with regard to the overall receiver performance such as noise temperature, power consumption, weight and physical size. The receiver works at room temperature, has a double sideband noise temperature as low as 2000 K at a maximum power consumption of 4.5 W with an Allan time of 10 s and a sideband gain ratio of 0.52. The performance of the spectrometer is demonstrated by absorption spectroscopy of H2O and CH3OH with an instantaneous bandwidth of 1.5 GHz and a resolution of 183 kHz. Several pressure broadening parameters of methanol absorption lines were determined, that agree with other published data. Using the experimentally determined molecular parameters the CH3OH absorption spectrum could be modeled with very high precision.
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| 25. |
- Neumaier, Philipp, 1984, et al.
(författare)
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Molecular spectroscopy with a compact 557 GHz heterodyne receiver
- 2013
-
Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035.
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Konferensbidrag (refereegranskat)abstract
- In this work the results of spectroscopic and performance measurements with a compact heterodyne receiver in the frequency range between 520 and 590 GHz are presented.
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