| 1. |
- Ahmed, S, 1970, et al.
(författare)
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Fractal-based dual-band small antenna for 2.45 and 5.8 GHz
- 2010
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Ingår i: 21st Micromechanics and Micro systems Europe workshop, 26-29 September 2010, Enschede, The Netherlands. ; , s. 108-111
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Konferensbidrag (refereegranskat)abstract
- Small antennas are becoming important andrequired for many domestic and commercial wireless applications.New design and first experimental results confirmingthe simulations of multi-band patch antenna optimized for the2.45 GHz and 5.8 GHz bands are presented. This design isbased on the practical considerations found for our Minkowski-based fractal antenna that predict the influence ofgeometry modifications on the frequency of operation.
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| 2. |
- Rusu, Mircea, 1936, et al.
(författare)
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Minkowski fractal microstrip antenna for RFID tags
- 2008
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Ingår i: 38th European Microwave Conference, EuMC 2008; Amsterdam; Netherlands; 27 October 2008 through 31 October 2008. - 9782874870064 ; , s. 666-669
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Konferensbidrag (refereegranskat)abstract
- The unique properties of fractals have been exploited to develop a new class of antenna element designs that are multi band and compact in size. These properties are very important for RFID (Radio Frequency IDentification) tags where the small size, planar geometries, multi band operation and low cost are essential for many applications. This paper presents a one loop Minkowski modified antenna using a unique configuration and operating at 868MHz and 2.45 GHz that has been realized on a Rogers Duroid substrate. Experimental results confirm the theoretical prediction. In addition, the principle applied in this design could be used to create even smaller devices by using different substrates.
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| 3. |
- Alavian Ghavanini, Farzan, 1978, et al.
(författare)
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A method to evaluate MEMS bonding
- 2006
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Ingår i: Micro Structure Workshop 2006. ; 1:1, s. 47-B3d
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Konferensbidrag (refereegranskat)
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| 4. |
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| 5. |
- Arndt, Holger, et al.
(författare)
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Real-time constant monitoring of fall risk index by means of fully-wireless insoles
- 2017
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Konferensbidrag (refereegranskat)abstract
- Constant monitoring of gait in real life conditions is considered the best way to assess Fall Risk Index (FRI) since most falls happen out of the ideal conditions in which clinicians are currently analyzing the patient's behavior. This paper presents the WIISEL platform and results obtained through the use of the first full-wireless insole devices that can measure almost all gait related data directly on the feet (not in the upper part of the body as most existing wearable solutions). The platform consists of a complete tool-chain: insoles, smartphone & app, server & analysis tool, FRI estimation and user access. Results are obtained by combining parameters in a personalized way to build individual fall risk index assessed by experts with the help of data analytics. New FRI has been compared with standards that validate the quality of its prediction in a statistically significant way. That qualitatively relevant information is being provided to the platform users, being either end-users/patients, relatives or caregivers and the related clinicians to ideally assess about their long term evolution. © 2017 The authors and IOS Press.
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| 6. |
- Bjurström, Johan, 1985, et al.
(författare)
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Tunable spring balanced magnetic energy harvester for low frequencies and small displacements
- 2022
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Ingår i: Energy Conversion and Management. - : Elsevier Ltd. - 0196-8904 .- 1879-2227. ; 259
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we present a novel concept to efficiently harvest vibrational energy at low frequencies and very small displacement. We describe and evaluate an electromagnetic energy harvester which generates power from a magnetic circuit with motion induced variations of an air gap. External vibrations induce oscillations of the gap length around an equilibrium point, due to a linear spring counteracting the magnetic force. The relative position of the spring can be adjusted to optimize the harvester output for excitation amplitude and frequency. A simulation model is built in COMSOL and verified by comparison with lab measurements. The simulation model is used to determine the potential performance of the proposed concept under both harmonic and non-harmonic excitation. Under harmonic excitation, we achieve a simulated RMS load power of 26.5 μW at 22 Hz and 0.028 g acceleration amplitude. From a set of comparable EH we achieve the highest theoretical power metric of 1712.2 µW/cm3/g2 while maintaining the largest relative bandwidth of 81.8%. Using measured non-harmonic vibration data, with a mean acceleration of 0.039 g, resulted in a mean power of 52 μW. Moreover, the simplicity and robustness of our design makes it a competitive alternative for use in practical situations. © 2022 The Author(s)
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| 7. |
- Bjurström, Johan, 1985, et al.
(författare)
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Unified Modeling and Analysis of Vibration Energy Harvesters under Inertial Loads and Prescribed Displacements
- 2022
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Ingår i: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417 .- 1454-5101. ; 12:19
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we extend the optimization analysis found in the current literature for single-degree-of-freedom vibrational energy harvesters. We numerically derive and analyze the optimization conditions based on unified expressions for piezoelectric and electromagnetic energy harvesters. Our contribution lies in the detailed analysis and comparison of both resonant and anti-resonant states while fully including the effect of intrinsic resistance. We include both the case of excitation by inertial load and prescribed displacement, as the latter has not been elaborated on in the previous literature and provides new insights. We perform a general analysis but also consider typical values of applied piezoelectric and electromagnetic energy harvesters. Our results improve upon previous similar comparative studies by providing new and useful insights regarding optimal load, load power and power input to output efficiency. Our analysis shows an exponential increase in the critical mechanical quality factor due to the resistive loss coefficient. We find that the ratio of mechanical quality factor to resistive loss coefficient, at resonance, increases drastically close to the theoretical maximum for load power. Under the same optimization conditions, an equivalent conclusion can be drawn regarding efficiency. We find that the efficiency at anti-resonance behaves differently and is equal to or larger than the efficiency at resonance. We also show that the optimal load coefficient at resonance has a significant dependence on the mechanical quality factor only when the resistive loss coefficient is large. Our comparison of excitation types supports the previous literature, in a simple and intuitive way, regarding optimal load by impedance matching and power output efficiency. Our modeling and exploration of new parameter spaces provide an improved tool to aid the development of new harvester prototypes.
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| 8. |
- Castillejo, Pedro, et al.
(författare)
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Aggregate Farming in the Cloud : The AFarCloud ECSEL project
- 2020
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Ingår i: Microprocessors and microsystems. - : Elsevier B.V.. - 0141-9331 .- 1872-9436. ; 78
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Tidskriftsartikel (refereegranskat)abstract
- Farming is facing many economic challenges in terms of productivity and cost-effectiveness. Labor shortage partly due to depopulation of rural areas, especially in Europe, is another challenge. Domain specific problems such as accurate monitoring of soil and crop properties and animal health are key factors for minimizing economical risks, and not risking human health. The ECSEL AFarCloud (Aggregate Farming in the Cloud) project will provide a distributed platform for autonomous farming that will allow the integration and cooperation of agriculture Cyber Physical Systems in real-time in order to increase efficiency, productivity, animal health, food quality and reduce farm labor costs. Moreover, such a platform can be integrated with farm management software to support monitoring and decision-making solutions based on big data and real-time data mining techniques. © 2020 The Author(s)
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| 9. |
- Enoksson, Peter, 1957, et al.
(författare)
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Wafer bonding for MEMS
- 2005
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Ingår i: Proceeding of the 9th International Symposium on Semiconductor Wafer Bonding: Science, Technology and Applic, Canadaations, Quebec City.
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Konferensbidrag (refereegranskat)
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| 10. |
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