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- Aliakbari Abar, Hanieh, et al.
(författare)
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Roof-Glass Integrated Antenna for Vehicular GNSS Applications
- 2024
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Ingår i: 2024 18th European Conference on Antennas and Propagation (EuCAP). - 9788831299091
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Konferensbidrag (refereegranskat)abstract
- In this paper, a wideband circularly polarized antenna is designed for integration into the glass roof of a modern car for GNSS positioning applications. Characteristic mode analysis is used to obtain more physical insight into the problem and hence satisfy the polarization and bandwidth requirements. The antenna has a low profile and uses a single coplanar waveguide feed to cover all GNSS bands. The measured 10 dB impedance bandwidth of the prototype is 52% and the 3 dB axial-ratio (AR) bandwidth is 39%. Full-car simulation results are presented for different antenna positions on the roof. It is shown that the middle and rear-right positions are preferred in terms of the AR performance.
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| 4. |
- Andersson, Henrik, et al.
(författare)
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Soldering Surface Mount Components onto Inkjet Printed Conductors on Paper Substrate using Industrial Processes
- 2016
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Ingår i: IEEE Transactions on Components, Packaging, and Manufacturing Technology. - 2156-3950 .- 2156-3985. ; 6:3, s. 478-485
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes mounting of standard surface mount component packages on a paper substrate using an industrial solder process with a low-temperature solder. The use of paper as a substrate for printed flexible electronics is becoming more and more widespread as an alternative to the more commonly used plastic substrates, such as polyethylene and polyimide. Paper has the benefits of being environmentally friendly, recyclable, and renewable, as well as inexpensive. It is shown that it is possible to mount standard surface mount device components on paper substrates using low-temperature solder in an industrial soldering process. The contact resistances obtained are mostly low, although the yield of functioning contacts is low. The reason is cracking of the substrate coating layer that goes through the printed silver tracks. It was observed that the cracks appear mostly close to the contact pads, the most likely cause is thermal mismatch between the coating layer and solder and also thermal expansion of the photo paper resin coating. The smallest component package size, 0201, resulted in the highest yield of >80% with decreasing yield for larger package sizes.
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| 5. |
- Bao, Erik L, et al.
(författare)
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Inherited myeloproliferative neoplasm risk affects haematopoietic stem cells
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 586:7831, s. 769-775
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Tidskriftsartikel (refereegranskat)abstract
- Myeloproliferative neoplasms (MPNs) are blood cancers that are characterized by the excessive production of mature myeloid cells and arise from the acquisition of somatic driver mutations in haematopoietic stem cells (HSCs). Epidemiological studies indicate a substantial heritable component of MPNs that is among the highest known for cancers1. However, only a limited number of genetic risk loci have been identified, and the underlying biological mechanisms that lead to the acquisition of MPNs remain unclear. Here, by conducting a large-scale genome-wide association study (3,797 cases and 1,152,977 controls), we identify 17 MPN risk loci (P < 5.0 × 10-8), 7 of which have not been previously reported. We find that there is a shared genetic architecture between MPN risk and several haematopoietic traits from distinct lineages; that there is an enrichment for MPN risk variants within accessible chromatin of HSCs; and that increased MPN risk is associated with longer telomere length in leukocytes and other clonal haematopoietic states-collectively suggesting that MPN risk is associated with the function and self-renewal of HSCs. We use gene mapping to identify modulators of HSC biology linked to MPN risk, and show through targeted variant-to-function assays that CHEK2 and GFI1B have roles in altering the function of HSCs to confer disease risk. Overall, our results reveal a previously unappreciated mechanism for inherited MPN risk through the modulation of HSC function.
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| 6. |
- Li, Xiaotian, et al.
(författare)
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A Paper-Based Screen Printed HF RFID Reader Antenna System
- 2018
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Ingår i: IEEE Journal of Radio Frequency Identification. - 445 Hoes Lane Piscataway, NJ 08854, USA : IEEE. - 2469-729X .- 2469-7281. ; 2:3, s. 118-126
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Tidskriftsartikel (refereegranskat)abstract
- Screen printing is a stencil process where conductive inks are patterned onto substrates through a fine mesh of threads. Nowadays, screen printing can be used to print RFID antenna structures onto flexible and ultra-low-cost substrates such as pa-per. In this manuscript, we present an HF RFID reader antenna system, operating at 13.56 MHz, using screen printed Ag particle ink as conductor and using HP photo paper as substrate. The proposed antenna system comprises four loop antenna elements, matched to 50 Ω, and one I2C addressed SP4T multiplexer circuitry, controlled through an exterior embedded system. The geometries, designs and characterizations of the antenna system are described in the manuscript in details. Measurement results show that the antenna system has low power reflections and a suitable Q factor. It has a maximum 11.1 cm RFID tag read range at an antenna system input power of 33 dBm. 2D RFID tag positioning can be enabled by utilizing the RFID tag interrogation zones formed by the four loop antenna elements. In addition, a parametric study is carried out to investigate the effect of loop antenna element DC resistance on the antenna element performance. It can be concluded that the proposed method can be used to create low-cost and large-area HF RFID reader antenna systems.
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| 7. |
- Li, Xiaotian, et al.
(författare)
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Enabling paper-based flexible circuits with aluminium and copper conductors
- 2019
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Ingår i: IOP Flexible and Printed Electronics. - Temple Way, Bristol BS1 6HG, United Kingdom : IOP Publishing. - 2058-8585. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Implementing electronics systems on paper is an important area of flexible circuit technologies. One of the approaches is to print conductive inks onto paper substrates, on which silicon-based surface mount device components are mounted. However, one of the problems is that the printed conductors have unneglectable resistivity. In this paper, we present paper-based flexible circuits, using copper and aluminium conductors that are laminated onto paper substrates using a high-speed roll-to-roll method. Edge roughness inspections and repeated two-point bending tests are carried out to evaluate the manufactured flexible circuits. Three surface mount techniques are used to assemble standard surface mount device components onto the flexible circuits, including an isotropic conductive adhesive, an anisotropic conductive adhesive, and a low-temperature solder paste. Several characterizations are performed to the surface mount techniques, including contact resistance measurements, component bonding strength tests, assembled circuit bending tests, and scanning electron microscopy. The results of the characterizations suggest that flexible circuits made from Cu with paper substrate achieve satisfactory results for mechanical reliability, all surface mount techniques, and have the potential to be used on automatic component assembly lines. In order to test whether such flexible circuits and surface mount techniques can be used in implementing electronics systems, passive NFC tags with relative humidity sensing functionality are made, which are interrogated by an NFC equipped mobile phone.
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| 8. |
- Li, Xiaotian
(författare)
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Flexible Circuits and Materials for Creating Large-Area RFID Reader Antenna Systems
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the applications for RFID technology is to monitor and position RFID-tagged objects over large volumes. To achieve this, one possible option is to implement RFID reader antennas, which are relatively thin but with significantly large areas, and place them beneath the RFID-tagged objects. In order to realise RFID reader antennas with large-areas, circuit materials other than conventional rigid PCB materials should be investigated and utilized. Therefore, this thesis addresses how non-conventional PCB materials can be used to achieve large-area RFID reader antenna structures. Non-conventional PCB materials are firstly chosen, which comprises patterned Al-polyimide foil, printed conductive Ag inks onto paper, polyethylene foam as antenna substrate. The physical and electrical properties of the materials are measured. These properties are later used in antenna simulations. In addition, assembly methods, e.g. circuit lamination and VIA fabrication, for the chosen materials are developed. Three novel surface mounting techniques are developed and characterized in this thesis. The techniques are developed for mounting SMD components onto tracks made by Al, a screen printed Ag flake ink, and an inkjet printed Ag nanoparticle ink. These techniques are characterized and evaluated by various methods, including contact resistance measurements, bonding strength tests, and microscopy studies. The characterizations show these techniques have achieved low contact resistance and sufficient bonding strength. Based on the previous efforts, two antenna systems, respectively operating on UHF (867 MHz) and HF (13.56 MHz) bands, are fabricated. The two antenna systems are designed into SP4T switching networks, using standard antenna elements as the loads of the network. The input RFID interrogation signals from commercial industrial RFID readers are directed into every antenna element periodically through the SP4T switching networks. Both antenna systems are characterized by means of various RF power attenuation measurements and passive RFID tag interrogation tests. It is shown in the results that both antenna systems have low RF attenuations, potentials to perform passive RFID tag positioning, and possibilities to be expanded to larger areas. In the end, based on the antenna system characterization results and design parameters, a great amount of calculation is performed in order to discuss how large the antenna system areas can be as well as how many antenna elements can be achieved in one antenna system.
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| 9. |
- Li, Xiaotian, et al.
(författare)
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Flexible Circuits and Materials for Large-Area UHF RFID Reader Antenna Systems
- 2018
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Ingår i: IOP Flexible and Printed Electronics. - : IOP Publishing. - 2058-8585. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- RF electronics commonly incorporate PCB-materials with low loss tangents, which limits its use for large-area applications due to its high cost. This work verifies one alternative solution how non-conventional flexible circuit materials can be used to manufacture large functional surfaces for RF-based applications. Laminated Al foils are used for conducting layers and a flexible foam material is used for substrate. An RFID reader system has been developed to demonstrate the functionality, comprising of eight microstrip antenna elements arranged in a SP4T switching structure covering an area of 1.2 m × 0.6 m. Each antenna element is individually addressable with aid of distributed digital and analogue multiplexer circuitry and it is shown how these components can be soldered directly onto the Al conductors. The constructed system shows good RF performance, both with regards to the materials and to the interconnections with the distributed multiplexer circuitry. It can perform far-field RFID tag reading above its surface without dead zones and the system characterization implies that the concept can be further expanded to cover geometrical areas up to 1000 square meters.
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| 10. |
- Li, Xiaotian, et al.
(författare)
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Flexible Circuits Based on Aluminum Conductor and Nonwoven Substrate
- 2019
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Ingår i: 2019 IEEE International Flexible Electronics Technology Conference, IFETC 2019. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728117782
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Konferensbidrag (refereegranskat)abstract
- Electronic textiles, integrating functional electronics circuits into fabric materials, are emerging as an important branch of flexible circuits. In this paper, we introduce a novel material combination for electronic textiles that can be used in implementing hybrid electronics. This type of circuits is fabricated by laminating patterned aluminum foils onto a nonwoven substrate in a high-speed roll-to-roll method. An isotropic conductive adhesive and an anisotropic conductive adhesive are used to assemble standard surface mount device components onto the fabricated circuits. The surface mount techniques are characterized by means of contact resistance measurements, component bonding strength tests, circuit bending tests, and scanning electron microscopy. An NFC tag with relative humidity sensing functionality is fabricated to evaluate the fabricated circuits to an electronic system level.
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