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Göteborg, Sweden

Llombart N.,Jet Propulsion Laboratory | Llombart N.,Complutense University of Madrid | Cooper K.B.,Jet Propulsion Laboratory | Dengler R.J.,Jet Propulsion Laboratory | And 5 more authors.
IEEE Transactions on Antennas and Propagation | Year: 2010

We present the design of a reflector system that can rapidly scan and refocus a terahertz beam for high-resolution standoff imaging applications. The proposed optical system utilizes a confocal Gregorian geometry with a small mechanical rotating mirror and an axial displacement of the feed. For operation at submillimeter wavelengths and standoff ranges of many meters, the imaging targets are electrically very close to the antenna aperture. Therefore the main reflector surface must be an ellipse, instead of a parabola, in order to achieve the best imaging performance. Here we demonstrate how a simple design equivalence can be used to generalize the design of a Gregorian reflector system based on a paraboloidal main reflector to one with an ellipsoidal main reflector. The system parameters are determined by minimizing the optical path length error, and the results are validated with numerical simulations from the commercial antenna software package GRASP. The system is able to scan the beam over 0.5 m in cross-range at a 25 m standoff range with less than 1% increase of the half-power beam-width. © 2010 IEEE. Source


Drakinskiy V.,Chalmers University of Technology | Sobis P.,Omnisys Instruments AB | Zhao H.,Chalmers University of Technology | Bryllert T.,Chalmers University of Technology | And 2 more authors.
Conference Proceedings - International Conference on Indium Phosphide and Related Materials | Year: 2013

We present the progress of the technological development of a full e-beam based monolithically integrated Schottky diode process applicable for sub-millimetre wave multipliers and mixers. Evaluation of the process has been done in a number of demonstrators showing state-of-the-art performance, including various multiplier circuits up to 200 GHz with a measured flange efficiency of above 35%, as well as heterodyne receiver front-end modules operating at 340 GHz and 557 GHz with a measured receiver DSB noise temperature of below 700 K and 1300 K respectively. © 2013 IEEE. Source


Neumaier P.F.-X.,German Aerospace Center | Richter H.,German Aerospace Center | Stake J.,Chalmers University of Technology | Zhao H.,Chalmers University of Technology | And 12 more authors.
IEEE Transactions on Terahertz Science and Technology | Year: 2014

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 CH3 OH absorption spectrum could be modeled with very high precision. © 2014 IEEE. Source


Drakinskiy V.,Chalmers University of Technology | Sobis P.,Omnisys Instruments AB | Zhao H.,Chalmers University of Technology | Malko A.,Chalmers University of Technology | And 3 more authors.
26th International Symposium on Space Terahertz Technology, ISSTT 2015 | Year: 2015

We present the progress of the technological development of a full e-beam based monolithically integrated Schottky diode process applicable for sub-millimetre wave multipliers and mixers. The process has been employed in a number of demonstrators showing state-of-the-art performance. Source


Bryllert T.,Wasa Millimeter Wave AB | Bryllert T.,Chalmers University of Technology | Vukusic J.,Chalmers University of Technology | Olsen A.O.,Wasa Millimeter Wave AB | Stake J.,Chalmers University of Technology
IEEE MTT-S International Microwave Symposium Digest | Year: 2010

We present the first demonstration of a broadband Heterostructure Barrier Varactor tripier, designed to cover a major part of the WR-8 waveguide band. The source comprises a waveguide housing, a six-barrier InP-HBV diode flip-chip mounted on an AIN microstrip filter circuit. The conversion loss 3-dB bandwidth was measured to 17 % at a center frequency of 112 GHz. The maximum output power was more than 15 mW for an input power of 300 mW. There are no mechanical tuners or DC-bias, which simplifies assembly and allows for ultra-compact design. © 2010 IEEE. Source

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