| 1. |
- Ali, Muhsin, et al.
(författare)
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Dielectric Rod Waveguide-based Radio-Frequency interconnect operating from 55 GHz to 340 GHz
- 2022
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Ingår i: 2022 47Th International Conference On Infrared, Millimeter And Terahertz Waves (IRMMW-THZ 2022). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- We present a novel concept for high-frequency interconnects based on dielectric rod waveguide structures, which show a broadband operating frequency range. The low cut-off frequency is set at 50 GHz by design, while the upper limit extends beyond 340 GHz. An experimental demonstration is presented to validate the concept. The presented RF interconnect approach covers several rectangular waveguide bands with potential to be extended to terahertz range.
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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- Drozdz, Piotr A., et al.
(författare)
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Highly efficient absorption of THz radiation using waveguide-integrated carbon nanotube/cellulose aerogels
- 2022
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Ingår i: APPLIED MATERIALS TODAY. - : Elsevier BV. - 2352-9407. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- This article presents the preparation, compositional and electromagnetic characterization of modified few-walled carbon nanotubes/nanofibrillar cellulose (FWCNT/NFC) aerogels integrated in a standard terahertz hollow waveguide and studies their operation as absorbers of electromagnetic waves in the WR-3.4 band (220-330 GHz). Hybrid aerogels consisting of different weight ratios of NFC and modified FWCNT are prepared by freezedrying and characterized through scanning electron microscopy and Raman spectroscopy, and then placed within waveguide cassettes in a simple, low-cost and efficient way that requires no special equipment. A broadband measurement setup is employed for examining the electromagnetic response of the materials. It is found that the materials are excellent absorbers with an average shielding efficiency of 66 dB in the best case and return loss above 10 dB across the band with a flat frequency response. FWCNT aerogels are assessed as a promising candidate for terahertz waveguide terminations.
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| 6. |
- Drozdz, Piotr A., et al.
(författare)
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Integrated CNT Aerogel Absorbers for Sub-THz Waveguide Systems
- 2022
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Ingår i: 2022 IEEE/MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM (IMS 2022). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 906-909
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Konferensbidrag (refereegranskat)abstract
- The ongoing development of sub-THz systems and applications has created a need for new absorbing materials which can be integrated in a simple, low-cost manner. Here, we investigate the properties of CNT-based aerogels in the range of 67-110 GHz and develop a simple technique for their integration. The aerogels are synthesised using standard techniques and then shaped using a laser cutter to allow for direct integration. The S-parameters of a total of four aerogel absorber samples are measured. The absorbers offer a return loss of up to 12 - 14.5 dB across the measurement band, with a maximum absorption 2.54 of 5 dB/mm The observed performance makes CNT aerogels extremely promising candidates for use in sub-THz waveguide systems and applications.
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| 7. |
- Drozdz, Piotr, et al.
(författare)
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W-band waveguide embedded nanofiber absorber
- 2021
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Ingår i: 2021 46Th International Conference On Infrared, Millimeter And Terahertz Waves (IRMMW-THZ). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- A novel type of absorber integrate into a standard WR-10 metal waveguide of is developed and measured. The absorber is based on alumina nanofibers covered with single or multi- carbon layers. Employing this technique for the CNT based absorbers offers a material with micron scales-oriented 3D microstructures, that is hybrid alumina nanofibers covered with carbon layer. These microstructures result in a low level of reflectance and good absorbance at 75-110 GHz frequency band due to the highly porous and low conductivity.
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| 8. |
- Kumar, Ashish, et al.
(författare)
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Contactless Cost-effective Polarizer for mm-Wave Dielectric Rod Waveguide
- 2022
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Ingår i: 2022 47TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES (IRMMW-THZ 2022). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- We present a method to control the polarization of guided waves in a mm-wave dielectric rod waveguide. A pair of optical posts is situated on either side of the waveguide, and this markedly raises the cutoff of the undesired mode. The isolation is 20 dB over a frequency span from (55-87) GHz. This can be viewed as a proof-of-concept for reconfigurable, general-purpose polarization control and dispersion engineering in mm-wave and terahertz-range dielectric waveguides.
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| 9. |
- Smirnov, Serguei, et al.
(författare)
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Generation of High-order Modes in Sub-THz Dielectric Waveguides by Misalignment of the Transition Structure
- 2022
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Ingår i: 2022 IEEE/MTT-S International Microwave Symposium - IMS 2022. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 479-482
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Konferensbidrag (refereegranskat)abstract
- Dielectric waveguides are a potential platform for future integrated THz electronics but are still challenging to interface with standard measurement equipment. The commonly used tapered transition to hollow metallic waveguides involves manual alignment, leading to measurement inaccuracies. In this paper, we report the effects of misalignment between a dielectric and a metallic waveguide in the W-band. The results indicate the excitation of unwanted high-order modes in the dielectric waveguide that are expected to degrade the performance, especially at higher frequencies.
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| 10. |
- Xenidis, Nikolaos, et al.
(författare)
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Dichroic absorption of aligned graphene-augmented inorganic nanofibers in the terahertz regime
- 2024
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Ingår i: Applied Materials Today. - : Elsevier BV. - 2352-9407. ; 39
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Tidskriftsartikel (refereegranskat)abstract
- This article investigates the dichroic properties of aligned γ-Al2O3 nanofibers coated with graphene in the terahertz (THz) regime, revealing significant variance in absorption based on the orientation of the electric field in relation to the nanofibers, arising from the anisotropic nature of the material. Samples are prepared in a hot-wall chemical vapor deposition reactor with varying growth times, resulting in 5 samples with increasing graphene content. Compositional characterization is carried out using scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The samples are characterized electromagnetically using two distinct measurement techniques. First, a novel waveguide measurement setup is deployed, wherein square waveguide cassettes are used to capture the anisotropic behavior of the material and equally measure both polarization states in 67–500 GHz. Then, the samples are characterized using terahertz time-domain spectroscopy up to 4 THz. Both techniques highlight absorption enhancement when the electric field is parallel to the fibers, opening new possibilities for THz devices using polarization filtering.
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