| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
- Bulcha, Berhanu, et al.
(författare)
-
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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| 5. |
- Jayasankar, Divya, 1994, et al.
(författare)
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A Broadband Conversion Loss Measurement Technique for Terahertz Harmonic Mixers
- 2024
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 14:3, s. 424-427
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Tidskriftsartikel (refereegranskat)abstract
- This letter presents an experimental characterization technique for assessing the performance of terahertz harmonic mixers across a wide frequency range. The total signal transfer loss of three mixers was measured in both up- and down-conversion configurations, and the conversion loss was determined through the solution of a linear system of equations. The proposed method uses LO signals with a frequency offset to ensure single sideband measurements, thereby eliminating the need for image-reject filters. The three-mixer method was verified by measurements of millimeter-wave mixers, which matched the traditional characterization method using a calibrated source and power meter. Given this successful millimeter-wave demonstration, we characterized three WM-86 Schottky diode ×4-harmonic mixers from 2.2 to 3 THz. This technique presents a notable advantage for conducting broadband mixer characterizations, particularly in the terahertz frequency regime which lacks tunable, wide-band sources.
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| 6. |
- Skinner, James, et al.
(författare)
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Interlaboratory Comparison Of S-Parameter Measurements In WM-380 Waveguide at Frequencies from 500 GHz to 750 GHz
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A recent measurement comparison exercise involving four participating laboratories was undertaken to establish understanding of the current state of the art of WM-380 rectangular metallic waveguide S-parameter measurement capabilities. This report details the comparison in which each participant measured four WM-380 waveguide devices operating from 500 GHz to 750 GHz. A summary of the results obtained is given, in addition to some observations and analysis.
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