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  • 1.
    Berglund, Martin
    et al.
    Uppsala University.
    Sturesson, Peter
    Swedish Defence University, Department of Military Studies, Military-Technology Division. Uppsala University.
    Persson, Anders
    Uppsala University.
    Thornell, Greger
    Uppsala University.
    Manufacturing Miniature Langmuir probes by Fusing Platinum Bond Wires2015In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 10, article id 105012Article in journal (Refereed)
    Abstract [en]

    This paper reports on a novel method for manufacturing microscopic Langmuir probes with spherical tips from platinum bond wires by fusing for plasma characterization in microplasma sources. Here, the resulting endpoints, formed by droplets on the ends of a fused wire, are intended to act as spherical Langmuir probes. For studying the fusing behavior, bond wires were wedge bonded over a 2 mm wide slit, to emulate the final application, and fused with different voltages and currents. For electrical isolation, a set of wires were coated with a 4 μm thick layer of Parylene before they were fused. After fusing, the gap size, as well as the shape and area of the ends of the remaining stubs were measured. The yield of the process was also investigated, and the fusing event was studied using a high-speed camera for analyzing its dynamics. Four characteristic tip shapes were observed: spherical, folded, serpentine shaped and semi-spherical. The stub length leveled out at  ~400 μm as the fusing power increased. The fusing of the coated wires required a higher power to yield a spherical shape. Finally, a Parylene coated bond wire was integrated into a stripline split-ring resonator (SSRR) microplasma source, and was fused to form two Langmuir probes with spherical endpoints. These probes were used for measuring the IV characteristics of a plasma generated by the SSRR. In a voltage range between  −60 V and 60 V, the fused stubs exhibited the expected behavior of spherical Langmuir probes, and will be considered for further integration.

  • 2.
    Bhatt, Parth
    et al.
    Instituto Tecnológico de Aeronáutica, Brasilien.
    Yano, Edgar Toshiro
    Instituto Tecnológico de Aeronáutica, Brasilien.
    Amorim, Joni
    Högskolan i Skövde.
    Gustavsson, Per
    Swedish National Defence College, Department of Military Studies, Command & Control Studies Division. George Mason University, USA.
    A Cyber Security Situational Awareness Framework to Track and Project Multistage Cyber Attacks2014In: Proceedings of the 9th International Conference on Cyber Warfare & Security, Academic Conferences Limited, 2014Conference paper (Refereed)
  • 3.
    Colonese, Emilia
    et al.
    Instituto Tecnológico de Aeronáutica, Brasilien.
    Parente de Oliveira, Jose
    Instituto Tecnológico de Aeronáutica, Brasilien.
    Yano, Edgar
    Instituto Tecnológico de Aeronáutica, Brasilien.
    Amorim, Joni
    Högskolan i Skövde.
    Andler, Sten
    Högskolan i Skövde.
    Gustavsson, Per
    Swedish National Defence College, Department of Military Studies, Command & Control Studies Division.
    Cyber Security for Middleware System Architectures2014In: Proceedings of the 9th International Conference on Cyber Warfare & Security, Academic Conferences Limited, 2014Conference paper (Refereed)
  • 4. Grahn, Sven
    et al.
    Pålsson, Kristina
    Lärobok i Militärteknik, vol. 7: Rymdteknik2007 (ed. 1)Book (Other academic)
  • 5.
    Ivarsson, Olle
    Swedish National Defence College.
    Systemjämförelse – NH-90 och MH-60R2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In 2001 Swedish FMV ordered 18 NH-90 medium heavy helicopters from NH industries. The purpose of the procurement was that the new helicopter 14 would become the Swedish armed forces new primary medium helicopter, able to solve both ground and naval missions. The deal consisted of 5 naval versions of helicopter 14 and 13 helicopters for ground operations. The naval version of helicopter 14 was supposed to replace the Swedish helicopter 4, which was decommissioned 2011. Helicopter 14 was planned to be delivered at 2011, but because of delays it is now predicted to be delivered at 2019.  

    Therefore in this assignment a system analysis has been conducted to determine which helicopter system the Swedish armed forces in theory would have profited most to procure. Helicopter 14 system, or the American commercial off the shelf solution, MH-60R Seahawk. The assignment has be conducted to conclude which of these two system solutions would be the most optimal for preforming anti-submarine warfare under Swedish conditions. But also external factors in the procurement will be examined such as procurement methods, political effects, both positive and negative and also aspects of multinational cooperation’s.        

    The results of the system analysis showed that helicopter 14 was the best system for the Swedish armed forces. However there was few decisive differences between the two systems, therefor more factors should be taken into account during the procurement of a new helicopter system, such as procurement methods, defense cooperation’s and extending the lifetime of the previous system.     

  • 6.
    Johnsson, Fredrik
    et al.
    SWEDEC.
    Vretblad, Bengt
    Swedish Defence University, Department of Military Studies, Military-Technology Division.
    Experimentally developed model for the design of protective measures against shaped charge jet penetration during EOD operations2014In: ISMS Annual Connference 2014: Armed Forces for 2020 and beyond Roles, 2014Conference paper (Refereed)
    Abstract [en]

    The wide use of light anti-tank weapons, such as rocket propelled grenades and the scattering of sub-munitions lead toa greatnumber of explosive remnants of war (ERW) containing shaped charge warheadsin different conflict areas. A serious problem is that, the explosive ordnance disposal (EOD) personnel lack adequate means for the design of protective measures against the jetfrom clearance of shaped charge ammunition. In this paper, based on a master thesis in military technology,a previously suggested calculation model1, is developed further. The objectiveis to create a tool that can be applied to EOD operationsand meet military requirements by consideration of the limited information availability, the short time frames, the working methods and the technology level that are characteristic for such operations.

    Full-scale experiments have been conducted to clarify the effects of conditions that are typical for EOD operations: protective measures built from sandbags with a long standoff distance to the ordnance. The results indicate that the hydrodynamic penetration theory is not suitable for these conditions,and,furthermore, thata sandbag construction provides significantly better protection against the jet than a homogeneous gravel construction.

    By disturbance analysis, the sensitivity of the individual parameters in the model is studied for typical errors. Subsequently, Monte Carlo simulation has been used to analyse the cumulative effect these errors can cause. The simulation results have then been the used to determine the model ́s margin of safety.

    To achieve the desired military utility it should be possible to use the model under field conditions, with limited time frames and without access to advanced calculating means. This has resulted in a simple diagram included in a completedesign tool.It is proposed to implement the toolin regulations and curricula for EOD operations in order to remedy today’s lack of decision support

  • 7.
    Khaji, Zahra
    et al.
    Uppsala University.
    Sturesson, Peter
    Swedish Defence University, Department of Military Studies, Military-Technology Division. Division of Microsystems Technology, Dept. of Engineering Sciences and Ångström Space Technology Centre, Dept. of Engineering Sciences, Uppsala University, Uppsala, Sweden.
    Klintberg, Lena
    Uppsala University.
    Hjort, Klas
    Uppsala University.
    Thornell, Greger
    Division of Microsystems Technology, Dept. of Engineering Sciences and Ångström Space Technology Centre, Dept. of Engineering Sciences, Uppsala University, Uppsala, Sweden.
    Manufacturing and characterization of a ceramic microcombustor with integrated oxygen storage and release element2015In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 10, article id 104006Article in journal (Refereed)
    Abstract [en]

    A microscale ceramic high-temperature combustor with a built-in temperature sensor and source of oxygen has been designed, manufactured and characterized. The successful in situ electroplating and oxidation of copper, and the use of copper oxide as the source of oxygen were demonstrated. It was shown that residual stresses from electroplating, copper oxidation and oxide decomposition did not cause much deformation of the substrate but influenced mainly the integrity and adhesion of the metal films. The process had influence on the electrical resistances, however. Calibration of the temperature sensor and correlation with IR thermography up to 1000 °C revealed a nearly linear sensor behavior. Demonstration of combustion in a vacuum chamber proved that no combustion had occurred before release of oxygen from the metal oxide resource.

  • 8.
    Knaust, Stefan
    et al.
    Uppsala University.
    Khaji, Zahra
    Uppsala University.
    Sturesson, Peter
    Swedish Defence University, Department of Military Studies, Military-Technology Division. Uppsala University.
    Klintberg, Lena
    Uppsal University.
    Characterization of dielectric properties of polycrystalline aluminum nitride for high temperature wireless sensor nodes2013In: Journal of Physics: Conference Series / [ed] Paul Mitcheson, London: Institute of Physics (IOP), 2013Conference paper (Refereed)
    Abstract [en]

    An aluminium nitride (AlN) passive resonance circuit intended for thermallymatched high temperature wireless sensor nodes (WSN) was manufactured using thick-lmtechnology. Characterization was done for temperatures up to 900C in both a hot-chuck forfrequencies below 5 MHz, and using wireless readings of resonating circuits at 15 MHz, 59 MHz,and 116 MHz. The substrate for the circuits was sintered polycrystalline AlN. Using a simpliedmodel for the resonators where the main contribution of the frequency-shift was considered tocome from a shift of the dielectric constant for these frequencies, the temperature dependency ofthe dielectric constant for AlN was found to decrease with increasing frequency up to 15 MHz.With an observed frequency shift of 0.04% at 15 MHz, and up to 0.56% at 59 MHz over atemperature range of 900C, AlN looks as a promising material for integration of resonancecircuits directly on the substrate.

  • 9.
    Persson, Anders
    et al.
    Uppsala University, Division of Microsystems Technology, Uppsala, Sweden; Uppsala University, Ångström Space Technology Centre, Uppsala, Sweden.
    Berglund, Martin
    Uppsala University, Division of Microsystems Technology, Uppsala, Sweden; Uppsala University, Ångström Space Technology Centre, Uppsala, Sweden.
    Khaji, Zahra
    Uppsala University, Division of Microsystems Technology, Uppsala, Sweden.
    Sturesson, Peter
    Swedish Defence University, Department of Military Studies, Science of Command and Control and Military Technology Division, Military Technology Systems Section. Uppsala University, Division of Microsystems Technology, Uppsala, Sweden; Uppsala University, Ångström Space Technology Centre, Uppsala, Sweden.
    Söderberg, Johan
    Uppsala University, Division of Microsystems Technology, Uppsala, Sweden; Uppsala University, Ångström Space Technology Centre, Uppsala, Sweden.
    Thornell, Greger
    Uppsala University, Division of Microsystems Technology, Uppsala, Sweden; Uppsala University, Ångström Space Technology Centre, Uppsala, Sweden.
    Optogalvanic spectroscopy with microplasma sources: Current status and development towards a lab on a chip2016In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, no 10, article id 104003Article in journal (Refereed)
    Abstract [en]

    Miniaturized optogalvanic spectroscopy (OGS) shows excellent prospects for becoming a highly sensitive method for gas analysis in micro total analysis systems. Here, a status report on the current development of microwave-induced microplasma sources for OGS is presented, together with the first comparison of the sensitivity of the method to conventional single-pass absorption spectroscopy. The studied microplasma sources are stripline split-ring resonators, with typical ring radii between 3.5 and 6mm and operation frequencies around 2.6 GHz. A linear response (R2 = 0.9999), and a stability of more than 100 s are demonstrated when using the microplasma source as an optogalvanic detector. Additionally, saturation effects at laser powers higher than 100 mW are observed, and the temporal response of the plasma to periodic laser perturbation with repletion rates between 20 Hz and 200 Hz are studied. Finally, the potential of integrating additional functionality with the detector is discussed, with the particular focus on a pressure sensor and a miniaturized combustor to allow for studies of solid samples.

  • 10.
    Persson, Björn
    Swedish Defence University, Department of Military Studies, Military-Technology Division. KTH Royal Institute of Technology.
    Assessment of Aircraft Radar Cross-Section for Detection Analysis2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Hiding from and surprising an opponent are tactics that have been used in warfare throughout history. They were features that aircraft originally possessed when they were first used in military operations. However, development of military technology is an endless struggle between advances in technology and counter technology. During World War II this struggle led to the development of a new technology called radar, which was designed to detect sea vessels and aircraft at a distance and deny them the element of surprise. This laid the foundation for modern air defenses and simultaneously created a need for aircraft to penetrate such defenses. Central to the tactics and technological development that followed from the deployment of radar on the modern battlefield is the radar cross-section (RCS) of aircraft, which dictates the range at which aircraft can be detected by radar. In this thesis some aspects of the RCS of aircraft in radar detection are investigated. A combination of experimental measurement of aircraft and digital model development of the RCS of aircraft has been used.

    From flight experiments, the uncertainty in aspect angle to a threat sensor, due to aircraft dynamics, is quantified for various aircraft. In addition, the RCS fluctuation behavior of a military jet trainer is investigated by dynamic in-flight measurement. The monostatic and bistatic RCS of an F-117 are modeled and findings show that spline interpolation provides superior accuracy when interpolating the RCS data. Smooth and conservative RCS models are suggested and a new RCS sampling scheme is presented. A model based on experimental data is suggested for determining the range of aspect angles that an aircraft is likely to orient towards a threat sensor, and experimental RCS data is compared to the classical Swerling radar target models.

    Possible consequences for military operations and the design of military systems are discussed and considerations for modeling the interaction between air defenses and aircraft penetrating those defenses are given.  

    This thesis should be of interest to military actors and the defense industry, since the analyses of the ability to detect aircraft using radar are important for military operations and their planning.

     

  • 11.
    Persson, Björn
    Swedish Defence University, Department of Military Studies, Military-Technology Division. KTH.
    Radar Target Modeling Using In-Flight RCS Measurements2017In: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 54, no 1, p. 284-291Article in journal (Refereed)
    Abstract [en]

    A flight experiment with the Saab 105 aircraft and the radar cross-section measurement system Arken has been performed at C and Ku bands. Two types of trajectories were flown and the flight state was recorded using inertial and satellite navigation equipment.  The data was used to recreate the flight in a simulator where aspect angles and range to the measurement system could be calculated. The measured radar cross-section as a function of time is presented and compared to various statistical fluctuation models, including the distributions used in Swerling cases. Findings show that the Generalized Pareto distribution fits the measured data best and that Swerling Case 2 is also a good candidate for describing the dynamics of the radar cross-section at Ku-band when the aircraft approaches the radar head on. The measured radar cross-section data was analyzed using the Fast Fourier Transform from which fluctuation rates for different carrier frequencies and trajectories could be estimated.

  • 12.
    Persson, Björn
    et al.
    Swedish Defence University, Department of Military Studies, Military-Technology Division. KTH.
    Bull, Peter
    Swedish Defence University, Department of Military Studies, Military-Technology Division.
    Empirical Study of Flight-Dynamic Influences on Radar Cross-Section Models2016In: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 53, no 2, p. 463-474Article in journal (Refereed)
    Abstract [en]

    In this work, measurements and a method for analyzing flight-dynamic effects on radar cross-section models for aircraft are presented. Flight-dynamic effects need to be considered when designing combat aircraft and creating target models for radar simulators. The work is based on flight data from three different types of aircraft: Piper PA-28 Archer II, Boeing 737, and Saab JAS 39 Gripen. Using inertial navigation and global-positioning systems, the motions of the three aircraft are recorded in flight. From the data, aspect angles toward a radar station located in the extension of the intended flight path are generated using a simulator. It is found that the major contribution to perturbations in aspect angles is due to the rotational degrees of freedom and that bivariate normal distributions are a good candidate for approximating the uncertainty in aspect angles for all three aircraft types. It is also found that each rotational degree of freedom is close to a normal distribution but that the parameter values of the distribution vary with altitude and aircraft type.

  • 13.
    Sigholm, Johan
    et al.
    Swedish Defence University, Department of Military Studies, Military-Technology Division.
    Larsson, Emil
    Svenska Dagbladet, Stockholm, Sweden.
    Determining the Utility of Cyber Vulnerability Implantation: The Heartbleed Bug as a Cyber Operation2014In: Military Communications Conference (MILCOM), 2014 IEEE, IEEE conference proceedings, 2014, p. 110-116Conference paper (Refereed)
    Abstract [en]

    Flaws in computer software or hardware that are as yet unknown to the public, known as zero-day vulnerabilities, are an increasingly sought-after resource by actors conducting cyber operations. While the objective pursued is commonly defensive, as in protecting own systems and networks, cyber operations may also involve exploiting identified vulnerabilities for intelligence collection or to produce military effects. The weapon zing and stockpiling of such vulnerabilities by various actors, or even the intentional implantation into cyberspace infrastructure, is a trend that currently resembles an arms race. An open question is how to measure the utility that access to these exploitable vulnerabilities provides for military purposes, and how to contrast and compare this to the possible adverse societal consequences that withholding disclosure of them may result in, such as loss of privacy or impeded freedom of the press. This paper presents a case study focusing on the Heart bleed bug, used as a tool in an offensive cyber operation. We introduce a model to estimate the adoption rate of an implanted flaw in Open SSL, derived by fitting collected real-world data. Our calculations show that reaching a global adoption of at least 50 % would take approximately three years from the time of release, given that the vulnerability remains undiscovered, while surpassing 75 % adoption would take an estimated four years. The paper concludes that while exploiting zero-day vulnerabilities may indeed be of significant military utility, such operations take time. They may also incur non-negligible risks of collateral damage and other societal costs.

  • 14.
    Sturesson, Peter
    Swedish Defence University, Department of Military Studies, Science of Command and Control and Military Technology Division, Military Technology Systems Section. Ångström Space Technology Centre (ÅSTC), Uppsala University, Sweden.
    Sense, Actuate and Survive: Ceramic Microsystems for High-Temperature Aerospace Applications2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In aerospace applications, but also in manufacturing, mining, energy industry and natural hazards, high temperature, corrosion, erosion and radiation, challenge the performance and being of hardware.

    In this work, high-temperature co-fired ceramic (HTCC) alumina and platinum have been used for a range of devices intended for aerospace applications at up to 1000°C.

    The thermomechanics of a pressure sensor was investigated, and the interfacing was attained by wireless powering and reading. However, read range was limited and sensitivity decreased with temperature. Silver, electroplated after sintering, was found to remedy this until it eventually alloyed with platinum.

    Copper was electroplated and oxidized for oxygen storage in a microcombustor, intended for sample preparation for optogalvanic spectroscopy (OGS) to indicate extraterrestrial life. Despite delamination, caused by residual stresses, the device operated successfully.

    Conversely, pre-firing metallization by integration of platinum wires was studied. Freely suspended, and despite heat-induced shape irregularities, these were found advantageous over screen printed elements for gas heating, and temperature and pressure sensing. By fusing off the wires, spherical tips, allowing for impedance monitoring of microplasma sources in, e.g., OGS, were formed.

    Microplasma sources can also be used for gas heating. This, together with screen printed and suspended resistive heaters, was evaluated in a microthruster, showing that plasma heating is the most effective, implying fuel consumption reduction in satellite propulsion.

    In conclusion, HTCC alumina microdevices are thermally stable and could benefit several aerospace applications, especially with the complementary metallization schemes devised here.

    Future developments are expected to include both processing and design, all with the intention of sensing, actuating and surviving in high-temperature environments.

  • 15.
    Sturesson, Peter
    et al.
    Swedish Defence University, Department of Military Studies, Science of Command and Control and Military Technology Division, Military Technology Systems Section.
    Bull, Peter
    Swedish Defence University, Department of Military Studies, Science of Command and Control and Military Technology Division, Military Technology Applications Section.
    On the Applicability and Military Utility of Microsystems in Military Jet EnginesManuscript (preprint) (Other academic)
  • 16.
    Sturesson, Peter
    et al.
    Swedish Defence University, Department of Military Studies, Military-Technology Division. Uppsala University.
    Khaji, Zahra
    Uppsala University.
    Knaust, Stefan
    Uppsala University.
    Sundqvist, Johan
    Uppsala University.
    Klintberg, Lena
    Uppsala University.
    Thornell, Greger
    Uppsala University.
    Thermomechanical stability and integrability of an embedded ceramic antenna with an integrated sensor element for wireless reading in harsh environments2013In: Journal of Physics: Conference Series / [ed] Paul Mitcheson, London: Institute of Physics (IOP), 2013Conference paper (Refereed)
    Abstract [en]

    This paper reports on the design, manufacturing and evaluation of a small, wirelessly powered and read resonating antenna circuit with an integrated pressure sensor. The work aims at developing miniature devices suitable for harsh environments, where high temperature prevents the use of conventional, silicon-based microdevices. Here, the device is made of alumina with platinum as conducting material. Ceramic green tapes were structured using high-precision milling, metallized using screen printing, and subsequently laminated to form stacks before they were sintered. The device’s frequency shift as a function of temperature was studied up to 900°C. The contributions to the shift both from the thermomechanical deformation of the device at large, and from the integrated and, so far, self-pressurized sensor were sorted out. A total frequency shift of 3200 ppm was observed for the pressure sensor for heating over the whole range. Negligible levels of thermally induced radius of curvature were observed. With three-point bending, a frequency shift of 180 ppm was possible to induce with a curvature of radius of 220 m at a 10 N load. The results indicate that a robust pressure sensor node, which can register pressure changes of a few bars at 900°C and wirelessly transmit the signal, is viable.

  • 17.
    Sturesson, Peter
    et al.
    Swedish Defence University, Department of Military Studies, Military-Technology Division. Uppsala University.
    Khaji, Zahra
    Uppsala University.
    Stefan, Knaust
    Uppsala University.
    Klintberg, Lena
    Uppsala University.
    Thornell, Greger
    Uppsala University.
    Thermomechanical properties and performance of ceramic resonators for wireless pressure reading at high temperatures2015In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 9, article id 095016Article in journal (Refereed)
    Abstract [en]

    This paper reports on the design, fabrication, and thermomechanical study of ceramic LC resonators for wireless pressure reading, verified at room temperature, at 500 °C and at 1000 °C for pressures up to 2.5 bar. Five different devices were fabricated from high-temperature co-fired ceramics (HTCC) and characterized. Alumina green tape sheets were screen printed with platinum paste, micromachined, laminated, and fired. The resulting samples were 21 mm  ×  19 mm with different thicknesses. An embedded communicator part was integrated with either a passive backing part or with a pressure-sensing element, including an 80 µm thick and 6 mm diameter diaphragm. The study includes measuring thermally and mechanically induced resonance frequency shifts, and thermally induced deformations. For the pressure sensor device, contributions from changes in the relative permittivity and from expanding air trapped in the cavity were extracted. The devices exhibited thermomechanical robustness during heating, regardless of the thickness of the backing. The pressure sensitivity decreased with increasing temperature from 15050 ppm bar−1 at room temperature to 2400 ppm bar−1 at 1000 °C, due to the decreasing pressure difference between the external pressure and the air pressure inside the cavity.

  • 18.
    Sturesson, Peter
    et al.
    Swedish Defence University, Department of Military Studies, Science of Command and Control and Military Technology Division, Military Technology Systems Section. Ångström Space Technology Centre, Dept. of Engineering Sciences, Uppsala University, Sweden; Division of Microsystems Technology, Dept. of Engineering Sciences, Uppsala University, Sweden.
    Klintberg, Lena
    Division of Microsystems, Dept. of Engineering Sciences, Uppsala University.
    Thornell, Greger
    Ångström Space Technology Centre, Dept. of Engineering Sciences, Uppsala University, Sweden; Division of Microsystems Technology, Dept. of Engineering Sciences, Uppsala University, Sweden.
    Pirani Microgauge Fabricated of High-Temperature Co-fired Ceramics with Integrated Platinum Wires2019In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 285, p. 8-16Article in journal (Refereed)
    Abstract [en]

    This paper presents the integration and pressure sensor operation of platinum bond wires in High- Temperature Co-fired alumina (HTCC). Devices were fabricated with a 50 μm diameter wire suspended across a 500 μm wide cavity in green-body state HTCC, electrically connected to screen printed alumina conductors. The substrate shrinkage during sintering to a cavity width of 400 μm causes the wire element to elevate from the cavity ́s bottom surface. Resulting devices were compared with reference devices, containing screen-printed sensor elements, as Pirani gauges operated at 100 °C in constant-resistance mode, and in dynamic mode with a feeding current of 1 A in a pressure range from 10-4 Torr to atmospheric pressure. Also, devices with wire lengths between 500 and 3500 μm were operated and studied in constant-resistance and dynamic mode. Lastly, a device is demonstrated in operation at a mean temperature of 830 °C. The results include wire elements with a consistent elevation from their substrate surfaces, with irregularities along the wires. The wire devices exhibit a faster pressure response in dynamic mode than the reference devices do but operate similarly in constant-resistance mode. Increasing the wire element length shows an increasing dynamic pressure range but a decreasing maximum sensitivity. The sensitivity is retained in high temperature mode, but the dynamic range is extended from about 10 Torr to about 700 Torr.

  • 19.
    Sturesson, Peter
    et al.
    Swedish Defence University, Department of Military Studies, Science of Command and Control and Military Technology Division, Military Technology Systems Section.
    Seton, Ragnar
    Uppsala Universitet.
    Klintberg, Lena
    Uppsala University.
    Thornell, Greger
    Uppsala University.
    Persson, Anders
    Uppsala Universitet.
    Effect of Resistive and Plasma Heating on the Specific Impulse of a Ceramic Cold Gas Thruster2019In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 28, no 2, p. 235-244Article in journal (Refereed)
    Abstract [en]

    Research and development of small satellites has continued to expand over the last decades. However, propulsion systems with adequate performance have persisted to be a great challenge. In this paper, the effects of three different heaters on the specific impulse and overall thrust efficiency of a cold gas microthruster are presented. They consisted of a conventional, printed resistive thick-film element, a freely suspended wire, and a stripline split-ring resonator microplasma source and were integrated in a single device made from high-temperature co-fired ceramics (HTCC). The devices were evaluated in two setups, where the first measured thrust and the other shock cell geometry. In addition, the resistive elements were evaluated as gas temperature sensors. The microplasma source was found to provide the greatest improvement in both specific impulse and thrust efficiency, increasing the former from an un- heated level of 44 s to 55 s when heating with a power of 1.1 W. This corresponded to a thrust efficiency of 53 %. This could be compared to the results from the wire and printed heaters which were 50 s and 18 %, and 45 s and 14 %, respectively. The combined results also showed that imaging the shock cells of a plasma heated thruster was a simple and effective way to determine its performance compared to the traditional thrust balance method.

  • 20.
    Sturesson, Peter
    et al.
    Swedish Defence University, Department of Military Studies, Science of Command and Control and Military Technology Division, Military Technology Systems Section. Uppsala Univ, Dept Engn Sci, Angstrom Space Technol Ctr, Sweden; Uppsala Univ, Dept Engn Sci, Div Microsyst Technol, Sweden.
    Zahra, Khaji
    Uppsala Univ, Dept Engn Sci, Div Microsyst Technol, Sweden.
    Lena, Klintberg
    Uppsala Univ, Dept Engn Sci, Div Microsyst Technol, Sweden.
    Greger, Thornell
    Uppsala Univ, Dept Engn Sci, Angstrom Space Technol Ctr, Sweden; Uppsala Univ, Dept Engn Sci, Div Microsyst Technol, Sweden.
    Ceramic Pressure Sensor for High Temperatures: Investigation of the Effect of Metallization on Read Range2017In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 17, no 8, p. 2411-2421Article in journal (Refereed)
    Abstract [en]

    A first realization of membranes by draping a graphite insert with ceramic green body sheets, and a study on the relationship between circuit metallization, made by double- layer screen-printing of platinum and electroplating of silver on top of platinum, and the practical read range of ceramic LC resonators for high-temperature pressure measurements, are presented. As a quality factor reference, two-port microstrip meander devices were positively evaluated. To study interdiffusion between silver and platinum, test samples were annealed at 500, 700, and 900 °C for 4, 36, 72, and 96 hours. The LC resonators were fabricated with both metallization methods, and the practical read range at room temperature was evaluated. Pressure sensitive membranes were characterized for pressures up to 2.5 bar at room temperature, 500 and up to 900°C. Samples electroplated with silver exhibited performance equal to or better than double-layer platinum samples for up to 60 hours at 500°C, 20 hours at 700°C, and for 1 hour at 900°C, which was correlated with the degree of interdiffusion as determined from cross- sectional analysis. The LC resonator samples with double-layer platinum exhibited a read range of 61 mm, and the samples with platinum and silver exhibited a read range of 59 mm. The lowest sheet resistance, and, thereby, the highest read range of 86 mm, was obtained with a silver electroplated LC resonator sample after 36 hours of annealing at 500°C. 

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