| 1. |
- Ali, Muhsin, et al.
(författare)
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Terahertz Band Data Communications using Dielectric Rod Waveguide
- 2022
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Ingår i: 2022 Optical Fiber Communications Conference and Exhibition, OFC 2022 - Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- A terahertz data link is presented using dielectric rod waveguide (DRW) at 300 GHz and complex modulations for speeds up to 120 Gbps. Performance comparison with WR-3 rectangular waveguide validates the low-dispersion behaviour of DRW.
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| 2. |
- Anoshkin, Ilya, 1980-, et al.
(författare)
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Single walled carbon nanotube quantification method employing the Raman signal intensity
- 2017
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Ingår i: Carbon. - United Kingdom : Elsevier BV. - 0008-6223 .- 1873-3891. ; 116, s. 547-552
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Tidskriftsartikel (refereegranskat)abstract
- A new technique for measuring the number of single walled carbon nanotubes (SWCNTs) and their concentration in a carbon nanotube layer is developed in this work. It is based on the G peak intensity of the Raman spectrum, together with precise mass and optical absorbance measurements. The dependence of the number of the carbon nanotubes on the phonon scattering intensity is observed. This method opens an opportunity for the quantitative mapping of sp2 carbon atom distribution in the SWCNT layers with a resolution limited by the focused laser spot size.
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| 3. |
- Anoshkin, Ilya V., et al.
(författare)
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Freeze-Dried Carbon Nanotube Aerogels for High-Frequency Absorber Applications
- 2018
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 10:23, s. 19806-19811
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Tidskriftsartikel (refereegranskat)abstract
- A novel technique for millimeter wave absorber material embedded in a metal waveguide is proposed. The absorber material is a highly porous carbon nanotube (CNT) aerogel prepared by a freeze-drying technique. CNT aerogel structures are shown to be good absorbers with a low reflection coefficient, less than -12 dB at 95 GHz. The reflection coefficient of the novel absorber is 3-4 times lower than that of commercial absorbers with identical geometry. Samples prepared by freeze-drying at -25 degrees C demonstrate resonance behavior, while those prepared at liquid nitrogen temperature (-196 degrees C) exhibit a significant decrease in reflection coefficient, with no resonant behavior. CNT absorbers of identical volume based on wet-phase drying preparation show significantly worse performance than the CNT aerogel absorbers prepared by freeze-drying. Treatment of the freeze-dried CNT aerogel with n- and p-dopants (monoethanolamine and iodine vapors, respectively) shows remarkable improvement in the performance of the waveguide embedded absorbers, reducing the reflection coefficient by 2 dB across the band.
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| 4. |
- Campion, James, 1989-, et al.
(författare)
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Ultra-wideband waveguide embedded graphene-based THz absorber
- 2021
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Ingår i: The 11th International Conference on Metamaterials, Photonic Crystals and Plasmonics, META 2021. - : META Conference. ; , s. 926-927
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Konferensbidrag (refereegranskat)abstract
- A novel type of absorber material integrated in a standard metal waveguide is developed for the ultra-wide frequency range of 67-500 GHz. The absorber is based on graphene augmented inorganic nanofibers which are deposited inside a metallic waveguide cassette, allowing them to be utilised in standard waveguide systems. The material’s microstructures result in a low level of reflectance (< -15 dB) and good absorbance (> 20 dB) from 110-500 GHz due to the porosity of the sample and attenuation caused by graphene, making them highly suited for wideband terahertz applications.
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| 5. |
- Campion, James, 1989-, et al.
(författare)
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Ultra‐Wideband Integrated Graphene‐Based Absorbers for Terahertz Waveguide Systems
- 2022
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Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X. ; 8:9, s. 2200106-2200106
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Tidskriftsartikel (refereegranskat)abstract
- This article presents novel graphene-based absorber materials which can be directly integrated in terahertz waveguide systems. A simple, low-cost integration method is developed, allowing graphene augmented inorganic nanofibers to be embedded inside a metallic waveguide. In contrast to existing absorbers, the ability to embed such materials in a metallic waveguide allows them to be integrated into complete terahertz systems for large-scale applications. The electromagnetic properties of such materials are then examined using standard network analysis techniques. A wideband measurement setup is developed to enable measurement of a single sample from 67 to 500 GHz, eliminating the need to fabricate multiple samples. The porosity of the integrated material leads to excellent electromagnetic performance across a wide range of frequencies. The samples are found to have a reflection coefficient less than −10 dB for frequencies above200 GHz, while their attenuation per unit length exceeds 35 dB mm−1. The low reflectivity of the material allows it to be used in systems applications where undesired reflections must be avoided. The electromagnetic shielding effectiveness of the material is assessed, with a total effectiveness of 20–45 dB observed for 0.84 mm thick samples.
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| 6. |
- Carpintero, Guillermo, et al.
(författare)
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Interconnection challenges on integrated terahertz photonic systems
- 2021
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Ingår i: OPTICAL INTERCONNECTS XXI. - : SPIE-Intl Soc Optical Eng.
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Konferensbidrag (refereegranskat)abstract
- We present the current challenges for high frequency interconnects, especially for calibrated measures of the frequency response of components operating above 100 GHz. This is the challenge addressed by the TERAmeasure Future and Emerging Technologies project, aiming to combine photonics and electronics to develop new paradigm in the millimetre and Terahertz frequency ranges, overcoming the current obstacles to better measurements, eliminating the frequency banded nature of rectangular waveguides and providing metrology-grade results across the full frequency range.
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| 7. |
- Chicherin, Dmitry, et al.
(författare)
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Analog-type millimeter-wave phase shifters based on MEMS tunable high-impedance surface and dielectric rod waveguide
- 2011
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Ingår i: International Journal of Microwave and Wireless Technologies. - : Cambridge University Press and the European Microwave Association. - 1759-0787. ; 3:5, s. 533-538
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Tidskriftsartikel (refereegranskat)abstract
- Millimeter-wave phase shifters are important components for a wide scope of applications. An analog-type phase shifter for W-band has been designed, analyzed, fabricated, and measured. The phase shifter consists of a reconfigurable high-impedance surface (HIS) controlled by micro-electromechanical system (MEMS) varactors and placed adjacent to a silicon dielectric rod waveguide. The analog-type phase shift in the range of 0–32° is observed at 75 GHz whereas applying bias voltage from 0 to 40 V to the MEMS varactors. The insertion loss of the MEMS tunable HIS is between 1.7 and 5 dB, depending on the frequency.
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| 8. |
- Chicherin, Dmitry, et al.
(författare)
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MEMS based high-impedance surface for millimetre wave dielectric rod waveguide phase shifter
- 2010
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Ingår i: European Microwave Week 2010, EuMW2010. - 9782874870163 ; , s. 950-953
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Konferensbidrag (refereegranskat)abstract
- Analogue type millimetre wave phase shifter based on a dielectric rod waveguide with adjacent MEMS tuneable high-impedance surface is proposed. Applying bias voltage to the MEMS varactors of the high-impedance surface allow controlling its effective impedance and consequently the phase factor of the propagation constant inside the waveguide. The measured phase difference between the phase shifter with adjacent high-impedance surface and phase shifter with low impedance surface is up to 378°. The insertion loss of the high-impedance surface as phase shifting element at 80-90 GHz is 0.5-2.7 dB depending on the distance to the dielectric rod waveguide.
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| 9. |
- Chicherin, Dmitry, et al.
(författare)
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MEMS tunable metamaterials surfaces and their applications
- 2010
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Ingår i: APMC 2010. - 9781424475902 - 9784902339215 ; , s. 239-242
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Konferensbidrag (refereegranskat)abstract
- Microelectromechanical systems (MEMS) are proposed as a technological solution for fabrication of metamaterials. This enables tunability of metamaterials effective properties and allows using metamaterials in wide range of applications. Low loss of the MEMS devices allows the metamaterials application to be extended to millimeter and submillimeter wave frequencies without compromising on performance. Electronic beam steering by MEMS tunable metamaterials at millimeter wavelength is considered and a prototype of a W band analog tunable phase shifter is demonstrated. The insertion loss of the fabricated MEMS tunable metamaterials surface varies from 0.7 dB to a maximum of 3.5 dB (at a resonance frequency). MEMS varactors have shown reliable and repeatable analog operation over 108 cycles.
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| 10. |
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