| 1. |
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| 2. |
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| 3. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Gain bandwidth of NbN hot-electron bolometer terahertz mixers on 1.5 um Si3N4 /SiO2 membranes
- 2007
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Ingår i: Journal of Applied Physics. ; 101:12, s. 124508-1-(6)-
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Tidskriftsartikel (refereegranskat)abstract
- The gain bandwidth of NbN hot-electron bolometer terahertz mixers on electrically thin Si3N4 /SiO2 membranes was experimentally investigated and compared with that of HEB mixers on bulk substrates. A gain bandwidth of 3.5 GHz is achieved on bulk silicon, whereas the gain bandwidth is reduced down to 0.6–0.9 GHz for mixers on 1.5 um Si3 N4 /SiO2 membranes. We show that application of a MgO buffer layer on the membrane extends the gain bandwidth to 3 GHz. The experimental data were analyzed using the film-substrate acoustic mismatch approach.
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| 4. |
- 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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| 5. |
- 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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| 6. |
- Baubert, Jean, 1976, et al.
(författare)
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IF Gain Bandwidth of membrane-based NbN Hot Electron Bolometers for SHAHIRA
- 2005
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Ingår i: IEEE Applied Superconductivity. ; 15:2, s. 505-510
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Tidskriftsartikel (refereegranskat)abstract
- SHAHIRA (Submm Heterodyne Array for HIghspeedRadio Astronomy) is a project supported by the EuropeanSpace Agency (ESA) and is designed to fly on the SOFIA observatory.A quasi-optic design has been chosen for 2.5/2.7 THz and4.7 THz, for hydroxyde radical OH, deuterated hydrogen HD andneutral atomic oxygen OI lines observations. Hot electron bolometers(HEBs) have been processed on 1 um thick SiO2 Si3N4stress-less membranes. In this paper we analyse the intermediatefrequency (IF) gain bandwidth from the theoretical point of view,and compare it to measurements.
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| 7. |
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| 8. |
- Bevilacqua, Stella, 1981, et al.
(författare)
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Fast room temperature THz microbolometers
- 2012
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Ingår i: 23rd International Symposium on Space Terahertz Technology.
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Konferensbidrag (refereegranskat)abstract
- We will present experimental and theoretical investigation of room temperature high speed THz detectors based on thin YBa2Cu3O7 films. These films have TCR of 0.35%/K, and can sustain large bias current densities. With a resistivity of 100-200 µOhm×cm for a film thickness of 50nm, it is very straightforward to impedance match such bolometers with planar antennas. The responsivity is a function of the bolometer planar dimensions and the films thickness. The currently achieved responsivity is 30 V/W and Johnson noise limited NEP is 70pW/Hz^0.5. The bolometer bandwidth is limited by the antenna bandwidth and spans from microwaves to over a few THz. Experimenatl investigation is done from 100GHz to 2.5THz. The measured response time is 2ns. We will also present results of the bolometer performance as their dimensions reduce to sub-µm.
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| 9. |
- Bevilacqua, Stella, 1981, et al.
(författare)
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Investigation of MgB2 HEB mixer gain bandwidth
- 2011
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Ingår i: International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz), 2011. - 2162-2027. - 9781457705083 ; , s. 1 - 2
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Konferensbidrag (refereegranskat)abstract
- THz mixers based on superconducting MgB2 bolometers were fabricated by photolithography and Ar-ion beam milling on sapphire substrates. The mixer gain bandwidth of 3.4 GHz, 2.3 GHz and 1.3 GHz were measured for 10, 15 and 30 nm films respectively.
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| 10. |
- Bevilacqua, Stella, 1981, et al.
(författare)
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Low noise MgB2 terahertz hot-electron bolometer mixers
- 2012
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 100:3
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Tidskriftsartikel (refereegranskat)abstract
- We report on low noise terahertz bolometric mixers made of MgB2 superconducting thin films. For a 10-nm-thick MgB2 film, the lowest mixer noise temperature was 600 K at 600 GHz. For 30 to 10-nm-thick films, the mixer gain bandwidth is an inverse function of the film thickness, reaching 3.4 GHz for the 10-nm film. As the critical temperature of the film decreases, the gain bandwidth also decreases, indicating the importance of high quality thin films for large gain bandwidth mixers. The results indicate the prospect of achieving a mixer gain bandwidth as large as 10-8 GHz for 3 to 5-nm-thick MgB2 films.
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| 11. |
- Bevilacqua, Stella, 1981, et al.
(författare)
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MgB2 Hot Electron Bolometers for THz radio astronomy
- 2012
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Ingår i: 23rd International Symposium on Space Terahertz Technology.
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Konferensbidrag (refereegranskat)abstract
- We discuss Hot Electron Bolometer (HEB) THz mixers made of superconducting Magnesium Diboride (MgB2) films. The films of 30 nm, 15 nm and 10 nm thick were deposited on sapphire substrates. The MgB2 HEBs were patterned as a bridge at the feed point of a spiral antenna. The performance of the devices was investigated with respect to the gain bandwidth (GBW) and the noise temperature. The GBW was measured via mixing two signal sources (BWOs at 600 GHz). For the given films thicknesses, the GBW was measured to be 1.3 GHz, 2.3 GHz and 3.4 GHz, which is larger than for the NbN HEB mixers made of the same films thicknesses. Using the Y-factor technique a noise temperature of 800 K at 600 GHz local oscillator (LO) frequency was measured for mixers made of 10 nm MgB2 film. Besides the films thickness, the gain and the noise bandwidths are functions of the films critical temperature, Tc. For 10nm films, with Tc=15K, a noise bandwidth on the order of 8GHz was measured. From these measurements and from the material parameters a GBWof 8 GHz (noise bandwidth >10GHz) is expected for 3-5 nm MgB2 films.
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| 12. |
- Bevilacqua, Stella, 1981, et al.
(författare)
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Study of IF bandwidth of MgB2 phonon-cooled hot-electron bolometer mixers
- 2013
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 3:4, s. 409-415
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Tidskriftsartikel (refereegranskat)abstract
- A noise bandwidth (NBW) of 6-7 GHz was obtained for Hot-Electron Bolometer (HEB) mixers made of 10 nm MgB2 films. A systematic investigation of the (IF) gain bandwidth as a function of the MgB2 film thickness (30 nm, 15 nm and 10 nm) is also presented. The gain bandwidth (GBW) of 3.4 GHz was measured for a 10 nm film, corresponding to a mixer time constant of 47 ps. For 10 nm films a reduction of the GBW was observed with the reduction of the critical temperature (Tc). Experimental data were analyzed using the two-temperature model. From the theoretical analysis, the electron-phonon time (τe-ph), the phonon escape time (τesc) and the electron and phonon specific heats (ce, cph) were extrapolated giving the first model for HEB mixers of MgB2 films.
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| 13. |
- Bevilacqua, Stella, 1981, et al.
(författare)
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Submicrometer MgB2 hot electron bolometer mixers
- 2013
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Ingår i: The 24th International Symposium on Space Terahertz Technology.
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Konferensbidrag (refereegranskat)abstract
- Phonon-cooled hot electron bolometer mixers based on MgB2 film are promising candidates for THz radio astronomy at frequency above 1 THz. The short electron-phonon interaction time and the high critical temperature of the MgB2 (39 K in the bulk), compared to other intermetallic compounds, make it suitable for applications where wide IF bandwidth and low noise are needed. The currently achieved gain and noise bandwidths are 3.4 GHz and 7 GHz for HEBs fabricated in 10 nm MgB2 films. The noise temperature of 800 K was measured at 600 GHz local oscillator (LO) frequency using the Y-factor technique.MgB2 has been demonstrated to be sensitive to the oxygen as well as water, therefore it makes the fabrication of sub-µm HEBs very challenging. HEBs were fabricated using electron beam lithography in 10 nm MgB2 films with a bolometer area in the range of 0.09 and 0.25 µm2. We report the performance of the devices respect to the noise temperature at LO frequency up to 2.5 THz. Using the isothermal technique the LO power requirement was estimated respect to the bolometer area. Based on the material parameters obtained from the experiments, the two temperature model simulations showed a gain bandwidth as large as 8-10 GHz for thin MgB2 films.
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| 14. |
- Blomberg, Patrik, 1992, et al.
(författare)
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On-wafer characterisation of resonant-tunnelling diodes up to 1.1 THz
- 2023
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Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035.
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Konferensbidrag (refereegranskat)abstract
- This paper presents on-wafer S-parameter characterisation of resonant-tunnelling diodes between 0.5 THz and 1.1 THz. Diodes with a peak current density of 532 kA/cm2 and a clear negative differential region have been fabricated. An on-chip Multi-Thru-Reflect-Line calibration kit was developed and utilised to achieve accurate S-parameter measurements up to 1.1 THz.
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| 15. |
- 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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| 16. |
- Bryllert, Tomas, 1974, et al.
(författare)
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Integrated 200–240-GHz FMCW Radar Transceiver Module
- 2013
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 61:10, s. 3808-3815
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Tidskriftsartikel (refereegranskat)abstract
- We present a 220-GHz homodyne transceiver module intended for frequency modulated continuous wave radar applications. The RF transceiver circuits are fabricated on 3 µm-thick GaAs membranes, and consist of a Schottky diode based transmitter frequency doubler that simultaneously operates as a sub-harmonic downconverting mixer. Two circuits are used in a balanced configuration to improve the noise performance. The output power is >3 dBm over a 40-GHz bandwidth (BW) centered at 220 GHz, and the receiver function is characterized by a typical mixer conversion loss of 16 dB. We present radar images at 4-m target distance with up to 60-dB dynamic range using a 30-µs chirp time, and near-BW-limited range resolution. The module is intended for applications in high-resolution real-time 3-D radar imaging, and the unit is therefore designed so that it can be assembled into 1-D or 2-D arrays.
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| 17. |
- Bulcha, Berhanu, et al.
(författare)
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1.9-3.2 THz Schottky Based Harmonic Mixer Design and Characterization
- 2015
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Ingår i: Proceedings of the 45th European Microwave Conference, Paris, France, 7-10 September 2015. - 9782874870392 ; , s. 837-840
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Konferensbidrag (refereegranskat)abstract
- The development of a Schottky diode based 1.9 -3.2 THz harmonic mixer with high conversion efficiency is described. The mixer will be used as part of an ambient receiver to enable phase locking of Quantum Cascade (QC) lasers. The mixer consists of quartz based LO, IF circuits and a GaAs based THz circuit with integrated diode. The RF input is a diagonal horn coupled to WM-86 rectangular waveguide, with size 86 μm by 43 μm. The waveguide is coupled to the diode using a waveguide probe with integral DC bias line. Measurements of the mixer were performed using a 2 THz solid state source and 2.5 THz Quantum Cascade(QC) laser, and yielded a conversion loss of 30 dB for 3rd harmonic mixing. This result is a 15 dB improvement from a previous harmonic mixer that was presented by our group.
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| 18. |
- Bulcha, Berhanu, et al.
(författare)
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Design and Characterization of 1.8-3.2 THz Schottky-based Harmonic Mixers
- 2016
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 6:5, s. 737-746
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Tidskriftsartikel (refereegranskat)abstract
- A room-temperature Schottky diode-based WM-86 (WR-0.34) harmonic mixer was developed to build high-resolution spectrometers, and multipixel receivers in the terahertz (THz) region for applications such as radio astronomy, plasma diagnostics, and remote sensing. The mixer consists of a quartz-based local oscillator (LO), intermediate-frequency (IF) circuits, and a GaAs-based beam-lead THz circuit with an integrated diode. Measurements of the harmonic mixer were performed using a 2 THz solid-state source and 2.6906 THz QCL. A conversion loss of 27 dB for the third harmonic mixing and a conversion loss of 30 dB for the fourth harmonic mixing were achieved. This is the first development of a wideband WM-86 (WR-0.34) harmonic mixer with a planar Schottky diode integrated on a beam-lead THz circuit that uses a lower LO harmonic factor for 1.8–3.2 THz RF frequency. Furthermore, this result represents the best Schottky-based mixer in this frequency range.
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| 19. |
- Bulcha, Berhanu, et al.
(författare)
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Development of 3–5 THz harmonic mixer
- 2017
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Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. - 9781509060504 ; , s. Art no: 8067104-
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Konferensbidrag (refereegranskat)abstract
- There is a high need for >2 THz room temperature direct-detectors/harmonic-mixers to characterize THz optical sources, phase lock THz-QCLs as LO sources for multi-pixel receivers, and realize absolute frequency calibration sources for applications in astrophysics, earth science, and remote sensing. Thus, we have developed a WM-52 (WR-0.22) harmonic mixer for the 3–5 THz operation. The design, fabrication and assembly of the THz mixer are discussed.
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| 20. |
- Bulcha, Berhanu, et al.
(författare)
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Phase Locking of a 2.5 THz Quantum Cascade Laser to a Microwave Reference using THz Schottky Mixer
- 2015
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Ingår i: 40th International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz 2015, Hong Kong, China, 23-28 August. - 2162-2027. - 9781479982721
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Konferensbidrag (refereegranskat)abstract
- The frequency of a 2.5 THz QCL are stabilized to sub-hertz accuracy by phase-locking to a stable 100 MHz microwave reference, using a 2.3–3.2 THz room temperature Schottky diode based harmonic mixer. The down-converted phase locked beat note is stable over a long term test.
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| 21. |
- Cabello Sánchez, Juan, 1992, et al.
(författare)
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A Capacitive-Gap Coupled Terahertz Planar-Goubau-Line Power Divider
- 2023
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 13:6, s. 698-703
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Tidskriftsartikel (refereegranskat)abstract
- The planar Goubau line is a single-conductor waveguide with a low attenuation constant at terahertz frequencies compared to other planar waveguides. However, its single-conductor nature complicates the design of circuit elements compared to multi-conductor waveguides, especially when impedance transformation is needed, like in the case of power dividers. In this paper, we present a power divider for a planar Goubau line based on capacitive-gap coupled lines, providing a matched input port. A 900-GHz equal power divider was fabricated on a suspended silicon membrane and was characterized with a Vector Network Analyzer and terahertz probes between 0.5 THz and 1.1 THz. Simulations and measurements are in good agreement, the measured input return loss is lower than 15dB at the design frequency, and the average coupler loss is estimated to be lower than 1 dB when de-embedding the feeding lines.
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| 22. |
- Cabello Sánchez, Juan, 1992, et al.
(författare)
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A Corrugated Planar-Goubau-Line Termination for Terahertz Waves
- 2023
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Ingår i: IEEE Microwave and Wireless Technology Letters. - 2771-957X .- 2771-9588. ; 33:6, s. 643-646
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Tidskriftsartikel (refereegranskat)abstract
- The planar Goubau line is a promising low-loss metal waveguide for terahertz applications. To enable advanced circuits and multi-port measurements based on planar Goubau lines, there is a strong need for broadband impedance-matched loads, which can be used to absorb the energy and minimize standing waves in a system. In this work, we propose a termination for planar Goubau lines based on an exponentially-tapered corrugated line, gradually increasing conductor losses while maintaining small reflections. The corrugation density is high enough to increase conductor losses without requiring an auxiliary low-conductivity material. A 400-µm long planar Goubau line load was fabricated on a 10-µm thick silicon substrate suspended in the air. Simulations of the load show excellent agreement with calibrated reflection measurements in the frequency range 0.5 THz – 1.1 THz. Above the cut-off frequency of around 580 GHz, the measured reflections are less than -19 dB, below the noise floor of the characterization setup.
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| 23. |
- Cabello Sánchez, Juan, 1992, et al.
(författare)
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Capacitively-coupled resonators for terahertz planar-Goubau-line filters
- 2023
-
Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 13:1, s. 58-66
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Tidskriftsartikel (refereegranskat)abstract
- Low-loss planar Goubau lines show promising potential for terahertz applications. However, a single-wire waveguide exhibits less design freedom than standard multi-conductor lines, which is a significant constraint for realizing standard components. Existing filters for planar Goubau line lack clear design procedures preventing the synthesis of an arbitrary filter response. In this work, we present a design for a bandpass/bandstop filter for planar Goubau line by periodically loading the line with capacitively-coupled ?∕2 resonators, which can be easily tuned by changing their electrical length. The filter’s working principle is explained by a proposed transmission-line model. We designed and fabricated a passband filter centered at 0.9 THz on a 10-?m silicon-membrane substrate and compared measurement results between 0.5 THz and 1.1 THz to electromagnetic simulations, showing excellent agreement in both ?11 and ?21. The measured passband has an insertion loss of 7 dB and a 3-dB bandwidth of 31%. Overall, the proposed filter design has good performance while having a simple design procedure.
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| 24. |
- Cabello Sanchez, Juan, 1992, et al.
(författare)
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Design, fabrication and S-parameter characterization of a planar Goubau line from 0.75 THz to 1.1 THz for near-field on-wafer biosensing
- 2017
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Ingår i: 8th International THz-Bio Workshop.
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Konferensbidrag (refereegranskat)abstract
- We present the design, fabrication and characterization of a Planar Goubau Line (PGL) from 0.75 THz to 1.1 THz intended for on-wafer near-field characterization of biological samples. A design method of the transition between the Coplanar Waveguide (CPW) and the PGL was developed for minimising reflections. In order to minimize losses and the propagation of substrate modes, the structures were fabricated on a 30 μm benzocyclobutene (BCB) substrate on top of a high resistive silicon that acts as mechanical support. The structures were characterized with on-wafer S-parameter measurements from 0.75 to 1.1 THz using Vector Network Analyser.
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| 25. |
- Cabello Sánchez, Juan, 1992, et al.
(författare)
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Multiline TRL Calibration Standards for S-parameter Measurement of Planar Goubau Lines from 0.75 THz to 1.1 THz
- 2018
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. ; 2018-June, s. 879-882
-
Konferensbidrag (refereegranskat)abstract
- We present a multiline Thru-Reflect-Line (TRL) calibration standard for Planar Goubau Line (PGL) which allows setting the calibration plane along the PGL and thus removing the effect of the embedding structure. This opens the possibility of characterizing PGL-circuits. The presented structures were used for calibrating S-parameters measurements between 0.75 THz and 1.1 THz to characterize a 1 mm long and 10 µm wide PGL. The line shows negligible dispersion with an effective relative permittivity of 2.0 and an attenuation constant lower than 0.35 Np/mm (0.65 dB/λ).
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